A few years back I started a thread "7mm Mashburn vs 7mm Wby?" https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/t Don't know what happened here..most of my post got deleted. ??? Anyways, Here are the results shooting the 175 LRAB and 70.0 grains of H4831. 3,080 average speed ES of 8 fps. .5 group [IMG]http://img.photobucket.com/albums/v705/su35/7mm%20WBY%20Mag/P1020702_zpsa892b5b6.jpg[/IMG]

Very nice!

My 7mm Weatherby Mark V ULW has a 26" barrel and gets just about the advertised 3200 with 160 Nosler Partition factory loads, 3-shot groups averaging .6-.7 at 100 yards. Don't think I'll be Mashburning anytime soon either.

I still don't savy how the Weatherby gets all that velocity without pressure and freebore.

Given equal barrels and pressure the Mashburn will outrun the 7mm Weatherby with 175 and heavier bullets....has to; it has more capacity.

I won't be going 7mm Weatherby anytime soon.Hagel proved it decades ago....the Weatherby is second fiddle.

It isn't unusual to see cases of slightly less capacity than another show roughly the same velocities with lighter bullets;usually the differences will be seen with the heavier bullets and this is where the larger capacity cases come into their own.

So I am not surprised to see SU35 get 3300 from a 7mm Weatherby; but I have also chronographed loads in the Mashburn that did 3300 fps with a 160 gr with no ill effects, even though I do not choose to run it that hard.3300 with a 150 seems pretty routine coming from those who have used them in the Mashburn.I haven't.


Besides, if I put a 7 Rem Mag on the bench next to a 7mm Weatherby and just compare the size of the cases, I am hard pressed to understand where all the additional velocity comes from...the body of a 7 Rem Mag case is actually larger,while the 7mm Weatherby has a longer neck; the case is 2.55 inches in length.

A 300 Win Mag case(from which the Mashburn is formed)has more capacity than either of the other two.

My '81 vintage Wby Mk V does 3050 with the Nosler 175 Partition and IMR 7828. I can't wait to try it with the LR Accubonds.

Bob,

The freebore flattens the pressure curve, which doesn't peak as steeply as in a conventional throat with the bullet seated close to the lands. Peak pressure is less, but the "area under the pressure curve" is greater, allowing the use of more slow-burning powder. This has been proven over and over again by pressure-testing. In fact if bullets are seated deeper in a conventional throat the same thing occurs.

The downsides? Accuracy can be mediocre unless the long throat is just slightly over bullet diameter. Otherwise the bullet can tilt slightly before entering the rifling. Throat erosion can widen the freebore enough to do this, though it takes a while, since throat has to not merely surface-crack (the early stage of erosion) but start to lose chunks of steel as cracked areas break off.

The Weatherby rifles I've shot over the past several years have all shot quite well, indicating the freebore is the correct diameter.

One thing I remember about shooting my 7mm Wby. handloads over an Oehler was the very low, sometimes single digit, extreme spread I'd see for five shot strings. This could be a nice thing for real long range shooting.

Yes, and very noticeable to me today.

The Hornaday manual list many loads that will reach 3,100 with the 175's and 3,300 with the 150s. I use those same loads to get the same speeds.

The only thing I see the Mashburn getting is more recoil.

Just got two boxes of 175 LRAB to test out in my 7wby..Like SU35's its a R700 and 24". Its been a great shooter, and does seem to produce velocities out of proportion for its case size..even with 180's.

John I have not done so in awhile but have had several 7 Rem Mags with throats cut for 160 gr bullets seated even with the base of the neck....this created some free bore no doubt and in those rifles I noticed that I did not hit that velocity/pressure "wall" as fast with the 7 RM that we sometimes see....and the cartridge was much better behaved.I also noticed those rifles gave high velocities with 140 gr bullets as well.

Actually I had one that took 70 gr H4831 and 160 NPT, which is nudging right there with the 7mm Weatherby max load from the Nosler manual.....

I wonder if the long throating had the same effect as the free bore of the Weatherby?

In any event I saw much the same effects from the 300 Win Mag doing the same sort of thing and one barrel, a Krieger SS 24" routinely did 3210 with the 180 gr bullet....I shot it for years that way.

In any event my only objective in going with the Mashburn was that I wanted 3200 fps or so from a 160 and over 3050 or so from a 175 from a 24" barrel...."easily". Figure I could not go wrong picking the bigger case,which proved to be exactly what I got.

Double radii.





I'm hurt.

SU35, have you determined the actual BC on the bullet yet?

laffin'

Of course...they are both good! Take either in a heartbeat over a 280AI.

Bob,

Aside from factory brass and ammo, the only practical difference between the Weatherby and the Mashburn is the Weatherby rounds will fit in a so-called .30-06-length magazine box of 3.3" or so. Which makes it possible to build them on standard 98 Mauser actions, which was a big deal when Roy Weatherby started out, and still was for a few decades afterward, due to so many cheap 98 actions being available. It's also why Winchester's series of belted magnums (.264, .300, .338 and .458) have an overall cartridge length of 3.34".

There are some, of course, who suggest that if the magazine box is longer you might as well do a 7mm STW, or even a 7mm RUM, rather than a Mashburn.

John: Well, I couldn't tell all this from a distance.

Never owned a 7mm Weatherby and didn't want one because brass is expensive,and I just came off a bad experience with 7mm Dakota brass(Norma).

Yes I could get Remington brass but didn't want that either.Besides I just did not trust the cartridge to give the velocities I wanted from a 24" barrel. Weatherby ammo is known for being fire-walled.In any event every source I went to shows the Mashburn as having greater capacity.

Minor point maybe but I would have been disappointed if the thing ended up being a warmed over 7 Rem mag with more expensive brass. I don't have the time nor the resources to try everything out there....

Didn't want an STW(BTDT) and it likes 26" barrels and doesn't give any more velocity than a Mashburn.

As to the action length business,just like a 300 Win Mag, the Mashburn will fit in a 30/06-length box.You just have to seat deeper. I set mine up for H&H length because I wanted to....not because I had to.

Page's rifle (that gave 3050 with the old 175 gr NPT)was a 30/06 length action...as was Hagel's FN Mauser before he started seating to longer OAL.

In the end I have been very happy with the cartridge and am not bothered by the wildcat thing,nor the results. It works perfectly. I am thinking of getting another.

I could be wrong, here, often am, but, the comment by "Reloader28" concerning the "Powell-Miller-Venturi-Radius" shoulder, as used in Weatherby's cartridges, makes me wonder?

I have long been under the impression that this was actually more a marketing ploy by Roy W. and the configuration really has little effect on the chamber then exterior ballistics of a given round?

As, I understand the situation, a larger case capacity, all other factors being equal, will give higher velocities, due to more powder burning which produces more of the pressured gases that propel bullets. So, I see little difference between a 30* standard, as in, .264WM case,( for example only, not specific to actual cartridge) and the "double radius" of a .270WEA. case?

My 26" factory P-64 Westerner bbl, will run the 125NP at an easy 3350-3375, all day and put these into sub-moa clusters, and I cannot "get" how the minor difference in shoulder shape would improve this?

Hmmmm, Bob, is ...thinking of getting another....

THIS, is an example of EXTREME "gunaholism" and my 50ish years of this insanity has shown me that it is an incurable affliction!

Probably, should sell ME that old beater of a Simillion you now have, eh..........

Kutenay,

I don't consider Roy Weatherby to be on the same level of genius as John Moses Browning. However, when it came to creating high velocity cartridges he chose double radius shoulders & freebore for a reason.

I do know that in drag racing applications, rounded (radiused) intake ports induce greater velocity in flow rate vs. turbulence in right angles.

kuteany: I'm like you.....when I like something, I get a spare.

In one of JOC's monthly columns in Outdoor Life in the early 60s, he covered the 300 Wby and his two rifle so chambered. In that article, he stated that Roy Weatherby had told him that used the double radius as a marketing ploy, not because he thought it contributed to performance.

At that time, I was a high school student and "Outdoor Life" was THE reading material I favoured over any other, especially the boring and useless textbooks we were forced to study.

I thought when I posted the above that I had read "J'0C" on this at that time and vaguely recalled what Rick has posted.

I dunno, but, I tend to doubt that the shoulders REALLY DO make any major difference in performance in this situation. I do recall MD's comments on "the rocket effect" from an article he published some years ago and my impression from shooting various rifles is that his conclusions were/are correct in this respect, but, I am a bit unclear as to the effects upon velocity?

Not yet, I'm hoping to get it out for distance on paper soon to really see what these bullets will do.
From what I have read, Nosler's BC hold true. I've never known them not to.

SU35
Nice groups!

Now you having me thinking that instead of a planned 300 WBY project this winter I will re-barreling a 257 Vanguard to 7mm WBY, a few flutes and the extra Back Country stock I have sitting in the safe would make a sweet faux 7mm WBY Back Country.

Funny my first experience on how good the 7mm Weatherby�s shot started nearly 40 years ago when a good friend got a 7mm WBY in a deal that the Bank of Denver was running, (I think it was Denver) you put up $2500 into one of their CD�s and got a Mark V instead of interest!

Anyone else old enough to remeber that bank?

Gentlemen,

Several years ago a friend dropped off a 7mm Weatherby. About that time I purchased a Corbin press to make bullets. I worked up the best load I could with Nosler Solid Base 150s. It was a factory rifle with no mods, not even a trigger job. It would routinely put five into an inch at 100 yards. What was a real surprise is it would put five of my 140's into half that.

By the way it really liked the original Barnes "X" bullets.

Oh, yeah, I remember that bank.

Bob,

If you'd looked up pressure-tested 7mm Weatherby data from present sources, you would have found the velocities you were looking for. In fact Nosler lists two 160-grain loads from a 24" barrel that are essentially 3200 fps.

I know the 7mm Mashburn will fit in a standard magazine, but unless the chamber has some freebore it won't match 7mm Weatherby velocities. It only holds maybe 4-6 grains more powder than the 7mm Remington Magnum, depending on the brass ad bullet, which ain't enough to get a 175 to 3050 from 22" barrel unless there's some firewalling or freebore involved.

I just built a 7mm mashburn and had the throat cut to 3.53 inches. I found that I was getting more velocity variation than I wanted and also not quite getting the velocity that some of you are getting with that round. I dropped the gun off at the smiths and am having him cut the throat out a bit longer. I believe that I told him to cut it so that the base of a 160 grain accubond will be seated flush with the base of the neck. I believe that the round when seated this way will just fit in the magazine and have an overall length of 3.67.

The gun should still shoot well with the extra throating, correct? If push comes to shove I can just load up one of the longer 175 grain accubonds to minimize jump to the rifling.

Can the 'smith make sure the throat is only a half thousandth over bullet diameter?

I would really like to see pressure data on a 7 RM std throat, a 7 RM with a throat matching a 7 Wby, then the bbl cut for a 7 Wby body, then cut to a Mashburn. I am guessing that a 7 RM with an optimized throat will do everything that needs doing.

Anyone want to chip in? I will send some bucks to JB for a barrel. Should be able to get it all done with the same tube. Use a Savage nut set-up for headspacing the barrel. Who is in? Need someone to cut the various chambers. Maybe Melvin or Echols or ?

I believe JB's formula for gain in velocity being a function of capacity and can't see the difference.

Mathman,
The question is, does the reamer have the correct dimensions. Has nothing to do with "the smith" and everything to do with the reamer dimensions.

Really? No shiit?

I know, I know, I've nitpicked semantics too.

Just checked Nosler online:
7 RM 150 grain 3.290 OAL has 78.0 capacity
7 Wby 150 grain 3.369 OAL has 81.4 capacity
So with the same throats and same OAL and same pressures there should not be much difference, right?

Always a good idea to eliminate all variables.

Mathman,
Not trying to harass you; just being precise, nothing more.

Guys: I just heard from another knowledgeable forum member who built one and has shot it....he seemed pretty happy with it and noted how the case swallowed large amounts of powder and delivered excellent velocities so far, but he has only worked with one bullet and powder...RL25 and 150 gr BT's. He has also had and is familiar with the 7mm Weatherby and 7 Rem Mag.

His words(he called me this morning)....the Mashburn is a big, easy going 7mm magnum case that so far delivers the velocity very easily.....I'm paraphrasing.He will post his results later.

79pa if you are having a problem getting the velocity I don't know what to tell you....you are the first out of maybe 12-15 people who have built one having that problem that I have heard from....I am losing count fast...

I know for a fact that you can long throat a 7 Rem mag till the cows come home and it will not deliver Mashburn velocities.

I did not build this rifle to keep everyone happy, convince anyone else that they should have one, or proclaim it the "best" 7mm Magnum on earth.

Nor did I build it to debate its merits with a bunch of people who don't have one and want to speculate on what it will do. I only post results I have received and what people who report back tell me.If that does not make you all happy, I don't know what to tell you .

I built it to make me happy and it has delivered exactly what guys like Page and Hagel said it would.Matter of fact...it is so "spot on",it's almost spooky.

No offense taken at all. You said what I meant. You caught me being sloppy, fair and square. My response to you was in jest.

You dont have to justify anything to anyone. but it seems like you are always reassuring yourself about the mashburn. The wby and mash do the same things. Not many guys like the weatherbys, no big deal to those of us that own them..We report what they are capable of but some dont want to hear it i guess.

Its kinda interesting that you say the mash has to outrun the weatherby cuz its bigger (i'm sure it can by a little)then you say that the STW doesnt gain anything over the mash?

How how difference is a 7mm Wby loaded with 160 grain bullets versus a 7mm Wby with a 175 grain! Obviously the 175 bullet means more recoil on your shoulder. But what about on Moose, Elk, Bears? Any difference in terminal performance?

When I discovered there was something other than thirty caliber I purchased a Klienguenther K14 7 Rem Mag with a 26" heavy barrel. After awhile I had a Douglas Premium Airgauge 28" heavy barrel installed. It was chambered for .300 Weatherby necked to 7mm. It sent the Nosler 160 at 3,360 feet per second and the 175 at 3,150 feet per second. It was my mountain and forest rifle.

Had the chance to bust a few more caps today, at 300 yds.

With a 100 yd sight in, my first shot hit 6" low at 300.
Shot into a stiff crosswind then gust came up hard I quit till another day. This gives me an idea of where I'm heading.

Looks encouraging at 1.4".....BC's look good, even better.

I clicked two moa on the dial, you can see the results.
This is what JBM says for a 100 yd zero for my dope.
300yds -8.8 drop -2.8 moa (My drop was 6" and I came up 2 MOA).....

Rick,

I am sure a gunsmith I know with a Pressure Trace system would do the chambering, testing, etc. for the right price, but what would be the point?

Here's a list of the 7mm magnums that have had plenty of load development done with electronic testing equipment: 7mm SAUM, 7mm WSM, 7mm Remington Magnum, 7mm Weatherby Magnum, 7mm STW and 7mm RUM. We know what they will do at pressures of 62-65,000 psi, with the SAAMI chamber/throat dimensions.

I don't know of anybody who's done the same testing with the 7mm Mashburn, partly because there is no standard chamber/throat for the 7mm Mashburn.

It's also established that guessing pressures without some sort of sophisticated equipment is impossible. This is exactly why the 7mm STW went from being a wildcat "safely" capable of pushing 140-grain bullets to 3600+ fps to a factory cartridge with 140's at 3350-3400. The "safe" wildcat handloads were pressure-tested and found to be 70,000 psi or even higher. This is because the traditional "pressure signs" don't usually show up until 70,000+ psi.

What we know about the Mashburn is that it gets X velocity in the rifles of some handloaders. We don't know what the pressures are, but do we do know the handloaders who get those velocities use traditional pressure signs to judge whether their loads are safe.

Like Bob, I don't really care about all this as long as he's happy with his 7mm Mashburn. But I also believe it would have been a lot easier to get to the same place, at known pressures, with a 7mm Weatherby or 7mm STW, depending on how long a magazine's desired.

Also, I loaded 76.0 grains of RL25 for an average of 3,160 mv.

Good accuracy as well. So, I can boast my speed up just like the Mashburn and still go comfortable at 3,080 too.

Nice....:)

rosco: I don't need any reassurance on the Mashburn....I see three of them shot regularly over a chronograph.And I get feedback regularly from people who also own and shoot them.Seems everyone ends up in about the same places velocity wise.



The only one's who seem to need "reassurance" are the people who don't own one and have never loaded for it.

My suggestion is that folks go load for the 7 Rem Mag in standard and long throat versions,the STW, the Mashburn, and the 7mm Dakota.I already have and know what I like..toss in the 7 mm Weatheby if you like but i won't...the case is too small for what I want,and I don't want to rely on freebore and maxed pressures to get the velocities I want.

If you want to to compare the STW to the Mashburn,you have my loads with H1000; compare them to loads for the STW in the Nolser manual.I an not at all inconsistent.

SU the Mashburn will beat that by 100 fps comfortably.From a 24 inch barrel....they are most definitely NOT the same.

SU35, thanks for the report. Despite wind your horizontal looks good. Initial indications are that the BC's are holding up. Update us when you longer. I hope I beat you to it!

BTW, love your range. Its slightly different down in the southeast. We have to cut lanes just to get a 100.

Bob, you're a trip!
If I ever need a cheerleader to champion a cause, I'm gonna call ya!

Actually, Bob, is among the most credible and articulate regular posters here on issues concerning hunting rifles, their appropriate uses and he bases his opinions on a level of ownership and use of a number of rifles that, to my mind, gives them the authority that few others here really have.

As I have posted in the recent past, Bob, reminds me strongly of the late Allen Day, who was also a poster for whose comments and real knowledge, I developed the greatest respect.

These guys, both somewhat younger than I and both articulate and rational observers/commentators on these topics,were/ are why I log onto the "Campfire" as I usually do and I wish we had more such genuine experts. I learn from Bob in at least 75% of his posts and I am not exactly a novice as well as having FAR too many bloody rifles to mess with.

So, while I totally agree with "MadMooner" here, I also read Bob's posts to learn serious aspects of our mutual obsession with fine thundersticks.

+1

The pearls of wisdom one finds on the Fire are priceless and well worth the effort of having to sort thru the "other stuff".

DF

Kute- I agree 100%.

Wow, Bob! Are you getting 3,260 mv shooting 175's? I shoot a 24" barrel too.

Cause that is what I am shooting, 175 grain bullets.

I thought I saw where you were shooting 175's at less than 3,200.

Does this imply that by seating bullets deeper in most non-Weatherby rifles, that velocities can be increased (with the given trade-offs stated)? It seems that quite a number of loads with slow powders do not use the full case capacity so there is often room. If this is so I would guess this would only hold up to some point.

David

The SAAMI drawing for the 7mm Wby. shows about 3/8" of freebore, which is way past the change you could get with reasonable seating depth variations.

John,
My generAl thoughts re pressure testing: the gains reported with wildcats are due to 70,000+ pressures. The prime example is the 243 AI. Would love to see an "apples to apples" comparison.

Bob,
I will willingly join the Mashburn Society when a factory produces ammo and brass. I am just too lazy to form cases now days. Besides I don't need more than 3150 because of the mid range rise problems and with today's bullets I don't need more than 145-150 grains. If more is required then get a 375 H&H.

mathman,
In my rifle, some Remington factory ammo was a bit over 0.1" from the lands. It seems straight forward to seat longer bullets such as 160 ABs another 0.1" or maybe 0.2" deeper.

Not quite 3/8 but maybe enough to have the stated effect?

What I don't know is:
* Is seating depth relative to the length that touches the rifle a measure of freebore?
* Is there a minimum COL established like a max COL?


David

I believe that he can! Do you think that the extra throat will hurt anything? I will be going from being able to seat the bullet to 3.53 to 3.68. Is that too much?

Ain't that the truth!!

This is 100 percent correct, many shooters believe the bullets jump a canyon when in fact they just slide through a very tight tube, I have measured all my Bee rifles and the bullet is very tight in the freebore tube.

David,

Though the pressure curve usually flattens when bullets are seated deeper in a conventional, short-throated chamber, there are problems that occur. First is that accuracy often suffers--though not always. Second is the shank of the bullet may end up too far down the neck to hold securely. Third is the powder charge often can't be increased because the rear end of the bullet takes up more room.

Rick,

I believe you're right about the 70,000 psi on wildcats, but we don't need to pressure-test any of the factory loads. The SAAMI maximum average pressure for the 7mm Weatherby and 7mm STW is 65,000 psi, just as it is for the 7mm SAUM, 7mm WSM and 7mm RUM. So the velocities they're getting, whether with factory ammo or SAAMI-member handloading data (such as Nosler's) have been pressure-tested at not more than 65,000 psi.

All we really need is for some 7mm Mashburn enthusiast to loan their rifle and handloads to somebody with a Pressure Trace or other strain-gauge setup, and we can find out what the pressures are.

lol i'd play if someone within reasonable distance of northeast pa had pressure testing equipment

Rick I know. I understand all that.

It's easy enough to stick a 145 LRX in a Mashburn. I could do that with a FF load,get 3150,and go hunting.Chuck used that bullet this year in his rifle

I have Bitterroots and will get around to other stuff when those are gone.


I have played around with free bore,and long throats, barrels with over sized grooves etc and seen results.These days I lean more toward "buying" some additional case capacity if I want more velocity. In putting this rifle together I did not want a cartridge that depended on any tricky barrel stuff to get the velocities I wanted....I went with the bigger case...so I got a Mashburn. I was just coming "off" a Dakota and knew what one wold do the other one would.

No doubt a pressure trace would tell a story. I would not be surprised to see my Mashburn loads at 65,000 psi but if so I don't think it's a problem to load a Weatherby that hot and not a Mashburn. If it read 70,000 psi so what...I'll back it off and still get plenty of velocity....I could even the playing field by giving the Mashburn 3/8" freebore, too....no trick involved at all.

Page sent his rifle to Remington for pressure testing and chronographing,and that load of his gave 3050 with the 175 NPT...yes I know todays pressure testing stuff is better but still someone measured it at some point.Beside we have better powders now... I can run a 175 gr at that velocity level in my rifle all day long using H1000 without ill effect. This is about 100 fps better than a 7 Rem Mag with a top load with that same bullet.

(Friend Kent D who used to post here is running all over North America with his rechambered Rem 700 knocking off everything from a record book desert sheep to elk and other stuff with a 175 TBBC at 3040 from his rifle.He's only taken all NA species 3 times.)

After a few firings my cases are not showing any sign of primer pockets opening up.

I have had exactly one "snafu" in all the load workup with my rifle. A load of 78 gr of Retumbo and a 160 gr NPT came over the chronograph at 3330....I saw the numbers and was afraid to open the bolt...but there was no ejector mark, no blown primer,no stiff bolt lift....I discarded the case and immediately knew it was TOO hot just based on the velocity.

Where did I get that load? I had backed off 1.5 gr from the top end load in the Nosler Manual for the same bullet with the 7mm Weatherby...so yes I think John is right when he says the free bore flattens the pressure curve.But no one will convince me the 7mm Weatherby is not being loaded to the gills to get what it gets ......it also goes to show what a tremendous safety margin I have when running a 160 gr at 3160-3200 fps.

Doc Bill on here and and others have used RL25 to get 3200-3250 with 160's...I would not want to push beyond that.I have seen enough 160 NPTs ad 160 AB's fly down range without a whimper at those velocities. from two other barrels here using RL25 and Retumbo.

I don't know what the big deal is anyway.....you'd think the cartridge were some new invention. .

It's been proven world wide in Page's hands with a 175 gr NPT at 3050 in the tropics of Africa and India,the cold of North America,New Zealand,the mountains of Central Asia, on 450+ head of BG,...... and by Hagel on everything here in North America at the same velocity levels, including grizzlies,elk, and Alaskan Yukon Moose.It probably has more world wide "experience" on more types of BG than any other 7mm magnum,factory or wildcat, and it's as thoroughly proven in the world wide BG hunting arena as the 300 Weatherby magnum (and some others) in terms of reliability on a wide variety of animals...I am certain if there had been any "problems" with it,those gents would have uncovered it.

My only regret with the cartridge is that I didn't build one 30 years ago.Doubt I'd have used anything much else for a lot of my hunting.

Bob,

I have a 7mm Weatherby custom built on a Remington M700 by Mcwhorter rifles. It is a dandy rifle and pushes a 160 accubond to 3150 fps with really fine accuracy.

I mention that rifle to say that McWhorter has done a lot of work with various custom 7mm magnum chamberings and he really likes the Weatherby but also chambers for the 7mm-300 Winchester and the 7mm STW.

He will tell you that if these rifles are chambered with comparible throats/leads,a bigger case will give you higher velocity at the same pressure or the same velocity at lower pressure.

Which is all I hear you saying,your Mashburn gives really good velocity without excessive pressures with the bullets you want to use.

It operates in a sweet spot,and what's not to like about that.

Have a nice season.

Bob, I can get the very same safety margin from my Weatherby, now. No problem.

From the Hornaday Manuel 9th edition. Shooting 175 grain bullets.

I shoot the max load of 75.9 grains of RL25 for 3,160 fps. It's probably at 65K.
I have also loaded 74.0 for 3,050. That load probably is at the lower pressures, and speed that you speak of and like.

Same speed and probably same pressures as you get.
No safety margin advantage by the Mash.

Free bore, whatever, it has worked for over 60 years. I haven't heard of any free bore rifles blowing up in my lifetime.

I bought a factory rifle and use recommended loads that are proven safe to get the very same thing you are getting.

I also use Federal brass of which I have had no problem finding. Nosler/Norma 270 Wby can easily be opened up with a stroke of a press as well.

Advantage Mashburn----0

John,
Thanks for the reply. I tried some factory Rem 7mm Rem mag ammo in my custom rifle and it shot much better than handloads. The factory cartridge length was such that the bullet was over 0.1 from the rifling. From this discussion I'm guessing it may be because the pressure is "better behaved". I'll try it with some handloads, which are more consistent and concentric than factory ammo but prior handloads were also loaded much closer to the rifling.

David

Oh, SU you meant you are moving a 175 gr 7mm bullet at 3160 fps? Sorry I misunderstood. Thought you meant a 160.

Quite a cartridge this 7mm Weatherby....

Not only does this 2.5 inch case with under 90 gr of capacity equal or exceed the Mashburn, it also moves a 175 gr bullet at higher velocity than the 7mm STW and the 7mm RUM,both of which have a lot more capacity.....sometimes exceeding those cartridges by as much as 100-200 fps; at least that's according to Sierra, Barnes, and Hodgdon data,none of which shows those cartridges hitting anywhere 3160 with a 175 gr bullet,as we are expectd to believe the 7mm Watherby does..

The only thing coming close is the 7mm RUM in the Nosler Manual.





So, I am now expected to believe that the 7mm Weatherby is the velocity equivalent of the 7 RUM? I'm sorry that I can't meet your expectations of "stupid". SU the logic completely escapes me and I don't believe this stuff for a second, not at sane pressures anyway.

Pretty remarkable magic for 3/8" of free bore. Wonder how and why it snuck past Page and Hagel so long ago.

Now I understand why Dober stopped posting here.




This place has gotten over the top for me.

If anyone cares to discuss the Mashburn (or anything else for that matter) they can feel free to PM me. If I don't respond, take a hint why and don't bother to try again....

I've often looked at the 270wby and 7mmwby numbers and said, "damn!"

And I'm expected to believe that the 7mm Mashburn is the
velocity equivalent of the 7 RUM?

According to the Nosler Manual

(comparing cartridges with bullets of like sectional density)

This is what Nosler shows.

The 300 win mag (base case for the 7mm Mashburn)case
holds 81.4 grains of water.

The 7mm Wby holds 82.0 grains of water.






And John Barness too? I guess the good folks at Hornaday are in the category as well.

Bob, my goodness, friend, its just a cartridge.



It didn't sneek by John Barnsness.

I'm going off published proven data from a Manufacture and getting the speeds they declare.

The Mashburn folks are going on what they hope or wish for and don't really know.

Now who is over the top?

SU35 your case volumes are off. The .300 Win goes 89-90 grs full to the top of the neck. My velocities are chronoed from a 24" barrel. The Mashburn has approx. 4 grs. more case capacity to the top of neck than the Bee and about 8 over the Rem. I don't have numbers for either case to the base of the neck.

No, they are not.

I'm going exactly by what NOSLER shows in Loading Guide #7 with a seated bullet.

This shows the REAL case volume.

Pg 375 shows the (water) case volume with a bullet SD of .248
7mm Wby 82.0
Pg 450 shows the (water) case volume with a bullet SD of .248
300 Win mag 81.1 (not to mention it would be slightly less than that due to the case being reduced from .308 to .284)

Also, in comparing the case capacity of a seated bullet with longer high BC bullets.

The 300 win mag 30/200 grain SD bullet of .301 has a capacity of 77.4 grains of water.

The 7mm Wby 28/175 grain SD bullet of .310 (longer) has a capacity of 80.0 grains for 2.6 grains more water capacity than the 300 win mag, case with seated bullets.

So, therefore, loading 7mm/175 grain Partitions, the 7mm Wby will have more case capacity than the 7mm Mashburn.

Is it not obvious that the Mashburn operates at high pressures and not the moderate easy going pressures that it's proponents "guess" at.


Prove me wrong......please. For Bob's sake! And all those others who bought into the Mashburn myth.

Oh the drama!!!!
All over a few cartriges that basically do the same damn thing.


Bob- don't forget to post a goodbye thread. I hear reporting your premature demise is also a proven tactic

yeah he could will me a few rifles just to make it believable.

haha

Nothing like ballistic gack arguements. The ghost of Dober would approve! Lunacy, but in a healthy way. Totally there myself..... (Grin)

This is getting really interesting now. For the past several years I've found Bob to be one of the most rational guys on the Campfire, and earlier in this thread even basically said, "Sure, why shouldn't Bob use his 7mm Mashburn if that's what he wants?"

But now Bob is the one denying handloading data that's been tested by not one but SEVERAL companies. He's insisting they're wrong, that the 7mm Weatherby Magnum couldn't possibly be doing what Hornady, Nosler, Norma, etc. say.

All of those companies are members of the Sporting Arms and Ammunition Manufacturers' Associated (SAAMI), a voluntary organization that consists of ALL the major ammo and firearm manufactuers. Their purpose is to make sure all ammo in a certain chambering not only fits in every SAAMI-member's rifle, but is safe to fire and comes as close as possible to the listed specifications--including pressures.

The many members of SAAMI use the most advanced modern electronic equipment available to test pressures, at consistent temperatures and humidities, indoors where the lighting makes sure chronographs costing several thousand dollars record the correct velocities. They know what the hell they're doing.

But Bob doesn't believe all this, apparently because he believes all the SAAMI members are in collusion, publishing false results to prop up Weatherby. That isn't the rational Bob I've read for so many years. Yeah, this is all ballistic gack, but....

I'm braced for what will inevitably will come....

Your logic on case capacity is flawed. You are comparing the two cartridges held to 30/06 OAL; in the case of the 7mm Weathervy Nosler data shows 3.360; and in the case of the 300 Win Mag,3.310 with a 180 gr bullet.

All of this has nothing to do with the Mashburn because my chamber( and those of friends who have built similar rifles) is set up for an OAL of 3.6" with a H&H mag box;so that the 175 gr Nosler Partition is not seated into the case at all. (emphasis added) he bullet is up in the neck where it belongs, not down into the powder space, which is the "right" way to set it up in the first place.

We won't even get into the differences in how much more case capacity is consumed by a 30 caliber bullet vs a 7mm bullet seated into the 300 Win Mag case the same distance....I ain't that good at math an it doesn't matter anyway.

In any event I have been all through this seating depth thing with Johnny B before, concerning the Mashburn.

But I can read, John.... and know what SAAMI is.


I notice that SU's load for e 175 ABLR was 70 gr H4831 for 3080 fps) and taken from the Hornady Manual,which shows a max load of 70.1 gr H4831 with the 175 gr Hornady bullet.

He then used that data, to load a 175 gr Nosler LRAB bullet (not a Hornady)in his 7mm Weatherby. Does not matter, right?

The fly in the ointment( and is a big one) is that the Nolser manual lists 70 gr of H4831 as MAX with its 160 gr bullet...and Nosler lists no loads for H4831 whtasover with the 175 gr bullet.

So, SU offers as evidence of the superiority of the 7mm Weatherby over the Mashburn, the Nosler MAX load for the 160 gr Nosler bullets.......with the 175 gr Nolser bullet....offering up the Hornady manual max load as "evidence" that he is a careful and prudent handloader ........and that we Mashburn people are bunch of dangerous nuts who drink KoolAid.


And then jumps up and down with glee because his 7mm Watherby delivered Mashburn level velocities....no small wonder. He was using a max load for a 160gr Nosler bullet with a 175 gr Nosler bullet.....no wonder the 175 ABLR did 3080....I ain't surprised! And people will continue to tell me no one pushes hard on the 7mm Weatherby!

C'mon.

And people are preaching...to me...about the sanctity of SAAMI specifications,and pressure guessing,and Mashurn KoolAid? And loading hot?


How many times have we heard Johnny B tell us that we can use 62 gr of h4831 with a Hornady bullet in the 270 because Hornady bullets have less bearing surface than other bullets from other manufaturers?.... and I know this because I blew a primer once by switching from a Hornady bullet to a Nosler bullet after dropping the charge only two grains.You learn some stuff the hard way.

So if we are to be completely consistent and I am to be spanked for ignoring all this SAAMI data I would gently suggest that SU, in attempting to prove his point, be held to the same standards and not exceed Nosler's recommendations for suggested maximum loads by using a 175 gr bullet with the Nolser maximum load for a 160.

But he loads every thing to the friggin' gills anyway so I see no reason why this half-assed comparison should be any different.


I knew all this when I called "bullshidt" to his comparison from page 1 of this thread but did not wish to embarrass anyone but you know what? [bleep] it.

Anybody else gotten anything bloody lately?




Tanner

Tanner

How close were you that you got Arterial Spray on the scope


Kids

Bingo...

Arguing the objectively "known" vs. the non-objectively "known" is sorta silly.

This is where Gack Mountain becomes the slipperiest, stinkiest hill to die on

WTF!? You shot Bob?

He was gonna FAKE his death!

If that was a 280ai or a Weatherby you shot him with, he's gonna be pissed!

That is a give Bob, to be expected, of course, and I can do the same thing and do, and my powder capacity is increased as well. That said, I strongly doubt you have the higher case capacity you think you have over the 7mm Wby.


You are probably running much higher pressures than you think you are as well.

I don't know what action you are using but it seems that if you are seating your bullet out that far in the 300 mag case, I think you would have trouble loading it into a 700 mag well.





Bob, I am well aware of the difference in Load Guides and noted it from the beginning. I also took note that there was not hardly a difference in bearing surfaces between the two bullets and Hornaday even used the data for their RN bullet as well.
That said, In using the Horn data I replicated their speed with an ES lower than ten. Had the bullet bearing surface made a difference, my experience has shown me that I would have had higher velocities than book due to higher pressures and would have erratic speeds as well. I'm not, they are spot on with the book.

So fly in ointment, I don't think so.

It's a 7mm Rem Mag, Bob was okay with it

BTW- I'm shooting 180gr Bergers out of my 7mm Rem Mag at 3300fps. It's not an overpressure load, there's just lots of free-bore.

Tanner

Moly is pure magic

I've loaded for the 7mm Mashburn (and continue to do so) and the 7mm Wby. You sir are out to lunch on case capacity. As a start.

Maybe so, but the bottom line is this, It doesn't matter, and I am loading by the book and getting book speed.

You can only guess with the Mashburn.


btw, lets see some pics of your 7mm Bee...

Deer must have been point blank cuase I know you can't hit anything you're aiming at with that scope, especially combined with the ring spacing.

No love for 3.5-10x40s SU?

DNZ mounts kick ass, BTW.

Tanner

No, and I've had my share. They are pretty much the same dimension as the 4.5x14. I would rather have the extra X's on the top end than and extra X on the bottom.

I have the LR version on the 7Bee. My favorite scope.

I find the 3.5-10 to be nicer to "get behind" than the 4.5-14 throughout the operating range. I'd have more of the latter but for that fact.

having owned everything from the 2-7x's and fixed 4x's to the 6-18x's from leupold, i'm coming to the conclusion that the 3.5-10 vx3 is my favorite of all of them. the new 3-9x VX2's are surprisingly good as well.

I agree.

Besides, if I can't see a deer at 10x well enough to shoot it, I'd have to have a Mashburn just to reach it.

Tanner- sprinkle a pinch of Blue Dot in there before you seat the bullet. 3500+ with 180's. Really takes advantage of the freebore. May be a little hot though.

Different strokes for different folks I suppose, but I personally can't stand the 4.5-14's, terrible eye box for me. The 3.5-10's are my favorite of the bunch.

I'd always heard of folks like that, never actually believed they exist, 'till now.

A few comments on the latest batch of gack on the 7mm's:

The maximum Hornady loads lists for the 7mm Weatherby are not necessarily at 65,000 psi. In fact they are probably not.

What Hornady (and Sierra) do is work up loads until they hit the maximum SAAMI pressure, then round the loads off to the nearest 100 fps. In fact they; may not even test-shoot the exact loads listed. Instead they probably go up grain-by-grain, the way most of us do, then plot a graph and list the powder charges that coincide with the 100-fps intervals.

As a result the loads for the 175's in the 7mm Wby. get cut off at 3100 fps, whether or not a slightly higher-charge loadwill get, say, 3162 fps at 65,000 psi.

While SU35 may have been strictly incorrect when he suggested the 7mm Weatherby's powder capacity is greater than the 7mm Mashburn's, he would be correct in stating the 7mm Weatherby's freebore allows it to use as much or more powder than cases with somewhat more capacity.

Personally, I like fixed 10x scopes on longer-range rifles, but that's just me.

I have an older M8 10x I should send in for turrets and a regular duplex reticle.

Yep, no problem, I was incorrect on the powder capacity. But it makes me wonder just really how much more the Mash has.

And please, lets not highjack my thread with scope talk.


In 2010 I sought answers about the 7mm Mashburn VS the 7mm Weatherby. This was before BobNH had a 7mm Mash built.
My thread here is a follow up to the one 3 years before.
This was not posted to bring anyone grief.

I sought 3200 fps with 160's in my 7mm Weatherby. Had I not cut the barrel from 26" to 24" I likely would have gotten there. My Mk V pushes 160's to 3184 fps at 1/2 moa.

That's good enough for me.

Seems to me it would be fairly apparent a substantially longer throat would increase the chamber capacity. Are you stating that is equal to an increase in case capacity?

I would guess it would be, but that is only a guess.


Apparently TAK is the reason for mattress tags

Great thread and a lot to be learned here.

I don't know shcid about rifles but I know enough to know that the difference between a Mashburn and a 7 Weatherby ain't enough to get mad about.

MadMooner,

"Chamber capacity" is one way to put it. I've used "functional powder capacity" too.

It all boils down to being able to use more powder, for more velocity, in a case with a certain amount of powder capacity for the caliber.

Someone, what are the SAAMI pressure standards for the 7 RM and the 7 Wby?

May as well go to the horses mouth...

http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfR.pdf

Yeah, SAAMI information has been on-line for a while now. It's not any big secret.

Absolutely.

Would also say my favorite source for loading data is Hodgdon because they give pressure data for loads. I really wish all manuals printed pressure data... in this day and age of chronographs, it strikes me as a smart thing to do. I extrapolate pressure from velocity without pressure testing gear.

Also, I understand the desire for something a little different (7 Mashburn)... my dear friend Mark Dobrenski loves the round. But realistically that may have more to do with his relationship with Bob Hagel than any illusion about what the Mashburn does or doesn't do differently than other 7 Mags (at least that's my take and I wouldn't presume to speak for him).

Mark's a smart fella and knows 100 fps either way amounts to nada. I've shot his Mashburn and watched it work on game. It's a fine round and I get a kick that he loves the round so much.

Me, if I wanted a 7 Mag I'd go with a 7 WSM.

But I have no need for anything Magnum...

I hate to say it, but anyone who handloads without proper pressure testing equipment is guessing.

The "Bee" was my brothers. With it he took much of what North America has to offer in his 20's DIY.

Baloney.

If you have access to pressure tested data you can extrapolate pressure via velocity.

This isn't rocket science... or maybe it is

Brad, I've been handloading for a long time. Using a chronograph and any other "conventional" pressure indicators I have yet to KNOW the pressure of any cartridge I've loaded for. There are far too many variables. Extrapolating data for the MSM is the same darn thing.

Exactly.

The people I have spoken with off-line about this thread,and who have experience with the 7mm Weatherby,say the velocity claims for the 175 load made here are malarkey.

The SAAMI table indicates that as well....even if a 3/8" freebore allows a bit more speed, it isn't enough to jump velocties up to the levels of an STW or RUM.

Got it.

4 to 6 more grains of powder in the Mash urn ain't much velocity gain without higher pressures

Higher pressure than "what"? The Weatherby? I doubt it.

It's common knowledge that the cartridge has always gotten the velocities Weatherby claims for it with a trick barrel and high pressures.

Take a look at the case dimensions of a 7 Rem Mag and a 7mm Rem Mag....the 7 Rem Mag case body is bigger....not by much but the two are so close that what one will do the other will do.Where it gets the additional capacity I do not know but suspect it is thinner brass....and I can tell you for sure you are not going to operate a 7 Rem Mag and 175 gr bullet anywhere near 3100-3150 with a 175 gr bullet.....not at sane pressures anyway.

Any time I want I can make a 7 Rem Mag that goes just as fast as a 7mm Weatherby and have done it and actually gone right to 7mm Weatherby data with some powders. It's the barrel/throat "trick moves" that do it.Plus 26" barrels. There is a reason most Weatherby rifles come with 26" tubes.

With "normal" throats, the 7mm Weatherby is no faster than a 7 Rem Mag.

The next step up in capacity above these two are the Dakota,the Mashburn, and the STW. I've had them all..the Mashburn is not much greater in capacity but it's certainly enough more that, based on its capacity,it gives more velocity,safely.All three have more capacity than a 7 Rem or Weatherby.

If I want a cartridge that reliably gives more velocity with heavy bullets than a 7 Rem Mag, the Weatherby is not the next stop.It's one of the other three.And even they are hard pressed to move a 175 gr bullet at 3100 fps or better....we can look it up and see it.

I may be "interpolating data", but I have been around enough to know how much velocity each is capable of without opening primer pockets and getting short case life.The differences may not be huge but they are there...just like going from a 300 WS to a 300 Win Mag....the Win Mag is capable of higher velocity...not by much; but it's there.

The notion that a 7mm Weatherby is "safe" with a 175 gr bullet at 3100 or more is ridiculous...especially considering the willy-nilly swapping of data that has gone on to establish the point. Personally I don't find any of the "evidence" in this thread remotely credible. It's nothing but swapping data and guessing with a wink and a nod by people who should know better.

I don't for every 10 percent increase in case capacity there is a 2.5 increase in velocity at the same pressure. That is in escapable

For grins let's assume a powder capacity of 80 grains an 8% increase in case capacity would increase to 86.4 rains less than a 2.5% increase in velocity at the same pressure

So let me get this straight...

You don't rely on a manual for pressure data and you don't rely on a chronograph to extrapolate pressure from velocity, even though pressure = velocity, and the velocities in the manuals come from pressure tested data.

You have your own pressure testing gear?

If not, what you're saying is you guess.

Which, of course, is why most wildcat rounds "out-perform" conventional rounds so dramatically...

Bob.
True story for you Bob.
Local gunsmith I know,not the guy building my current stuff.Built a 7mm Weatherby for one of his customers.
Customer insisted on a custom chamber without the standard free bore.
Gunsmith agrees to do the work but be cautious about only usuing hand loads for the 7.
Customer says he only shoots handloads.

Several years later. Gunsmith gets a call from Customer.
Big time problem with his Weatherby and he needs to get it fixed.
Turns out the guy had gone on an elk hunt and some how during the trip out, had forgot his ammo.
He picked up a box of Weatherby ammo and used it sight his rifle in before the hunt.

The rifle was built on a M98.Turns out the M98 really can handle gas leaks without blowing up and killing the shooter pretty well.Big time case head leak.Bolt stuck in the rifle.
case head,after they finally got it out, pretty much incinerated.Just looking at,I actually saw the after math.
The guy was lucky he didnt eat it.
Thats what happens when you run Weatherby factory ammo is a chamber set up without free bore.
Weatherby factory ammo is some of the hottest loaded stuff you will ever run across.

I had a 7mm Weatherby in a Mark IV back in the early 80s before I did my Alberta hunts.
I could not equal factory ammo for speed with my handloads.
When I got close.I blew primers.
I know what they say about an example of one.
But for me, one was enough.
The Weatherby accuracy guarantee is 3 shots into a 1.5 inch group at 100 yards.
And thats exactly what I got.
The hotter I loaded it the bigger the groups got.
I found over time the only way it would go sub MOA was to down load it to 7-08 speed and then it was dandy accurate.
But thats not why I bought it.

My last factory built rifle the 7mm Weatherby.
After messing around with the thing for as long as I did and not getting anywhere.I finally got fed up and sold it.
My next rifle was built by Walt Bergers brother Nelson Berger.A M700 in Mr. Ackleys fine shooting 280.
I carried the 280 AI all over NA and Canada and never looked back.Didnt own a Magnum of any kind untill I finally built a 300 WM in 2000.

I have built a few more mags over the last 10 years or so.
Took awhile for the Weatherby magnum scar to wear off.


dave

I see this thread has wandered even further into the theoretical since last evening.

Yes, you can extrapolate pretty closely on pressures if you know what you're doing, and a chronograph is the #1 way to do it. I've done it a bunch of times, and been able to test my loads with either strain-gauge equipment, or have a piezo-electronic laboratory test them.

I see Bob still insisting the 7mm Weatherby Magnum gets it's results with too-high pressures, despite all the pressure-tested data to the contrary. I just happened to do an article on the 7mm Weatherby recently, and have the Nosler and Norma maximum-velocity 160-grain handloads for it and some other 7mm magnums at hand:

7mm Wby. Magnum Norma 26 inches 3199
7mm Wby. Magnum Nosler 24 inches 3197

7mm Rem. Magnum Norma 26 inches 3084
7mm Rem. Magnum Nosler 24 inches 3077

7mm STW Norma 26 inches 3176
7mm STW Nosler 26 inches 3229

7mm RUM Norma 26 inches 3186
7mm RUM Nosler 26 inches 3261

Somebody will no doubt point out that Norma is a European company, and the SAAMI equivalent over there is the Commission Internationale Permanente (C.I.P.), which uses a slightly different piezo-electronic set-up to measure pressures. But Norma is also a member of SAAMI, so adheres to their guidelines.

Also, Western Powders runs one of the larger pressure labs in the country, which does a lot of testing for other companies as well. They've done some experimenting with C.I.P. piezo barrels to see what the actual difference was, rather than speculate about it, and found there was around 1000 psi difference.

The reason most companies don't publish pressure data (though Western also does, for Accurate and Ramshot powders) is that reloaders are very much likely to extrapolate what they can do, and possibly get into trouble. For one thing, the pressures listed by Hodgdon and Western are Maximum Average Pressures (MAP). There are a couple of other pressure standards that cartridges have to meet, one being how much pressure varies from average on the HIGH side, since individual rounds can vary considerably. This also affects the MAP either SAAMI or C.I.P. select for a certain round.

Also, you can be assured that any load found in any current source of SAAMI-member data does not exceed the MAP of that cartridge, so that limit in pressure is implicit in any data.

Uh-oh.

Step back from the ledge, Bob.

Now John, don't start injecting facts into this thread... what fun is that?

No, they are full of malarkey.... Have these mystery people shot the Hornaday 175 data? Probably not.



And you keep telling us that your Mashburn does. "With safe pressures" ??


Interesting that I use Hornaday load data and get the exact speeds. Wonder why??
Anyone here want to venture?






Well said Brad, Funny, "these guessers" know everything and yet have never pressure tested their own Mashburn data or test shot any 175's out of a 7mm Wby.

They should shut their mouths till they do.

You are making my point Brad. I told you I have never, ever, ever, no never KNOWN what pressures my handloads are running at. I simply can't. It's a flippin guess. I have at least a dozen reloading manuals that I reference. But I can almost guarantee you that my pressures at their speeds are not the same as their pressures. Pressures are a best guess based on the information I'm dealing with. That includes the Mashburn.

So where should I be velocity wise with 175's in a long throated 7MM Mashburn Suoer Short?

Mule Deer,

The info you posted is supports my discovery. I purchased a 26" barrel 7 Rem Mag. After working up loads and hunting with it for awhile I rechambered it to the STW and hunted with it for awhile. Then I had it opened up to the RUM. The STW was a little faster than the 7 Rem and the RUM was only 25 feet faster than the RUM. It is interesting the STW was by far the most accurate in that barrel.

Brad,

I agree with your comments, but let's remember that TOTAL pressure = velocity, not peak pressure. And that is what complicates life with different burn rates and powder behaviour- peak pressure and total pressure are not always necessarily perfectly correlated. But generally speaking, peak pressure rises with velocity in a linear manner that can be extrapolated from known pressure-tested data, assuming all variables are kept as constant as possible (bullet, powder, primer, brass, distance from bullet to lands, chamber and bore dimensions, etc).

You must have missed the part of my recent post where I've done a lot of testing of "guessing" pressure with a chronograph by comparing the results to SAAMI loading data. Yes, you can come very close to estimating pressures with chronograph results. I've done it dozens of times.

In fact when the .300 WSM was so new there wasn't any SAAMI reloading data, a magazine assigned me to work up some loads, in order to beat the competition with the first .300 loading data around.

I compared the powder capacity of the .300 WSM with the .300 Winchester Magnum, using water and a bullet seated to the same depth in fired cases. Using a simple internall ballistics formula, I figured the .300 WSM should get 98% of the velocity of the .300 Winchester Magnum, so worked up some loads with popular .300 Winchester Magnum powders using that guideline.

My loads were published in HANDLOADER magazine, and when pressure-tested data came out over the neat year, only two of my 10 or so loads varied an entire grain from the pressure-tested data--and one of those was a grain under. The others we either spot-on or within a half-grain. And that's just ONE example among many of using a chronograph to estimate pressures.

As another experiment, I once loaded for the .270 using all the the traditional pressure signs, including measuring case-head diameter, to what were apparently "safe" levels. I then took of the same ammo to a piezo lab, where it tested almost 68, 000 psi.

Now, I did ignore velocity as an indicator in that test--and it turned out that the velocity I was getting was faster than any published data, and the powder charge also higher than any listed for that bullet weight.

Yes, there are ways of guessing pressures that are more accurate than bolt-lift and primer pocket tightness.

Jordan, I get all that and agree.

Still, saying that a /thoughtful/careful/eyes-wide-open handloader who will not push an agenda, can't get a sense of safe pressure via pressure tested data and an average velocity across his chronograph (adding or subtracting velocity for barrel length differences), while keeping an eye on brass life and "traditional pressure signs" is, well, dumb beyond belief.

This is great. So what is your best velocity "guess" in a 24" barrel for the 175 partition say in a long throated 7mm Mashburn Super Short magnum?

Umm Brad. That is what I do. EVERY single time and I apply that knowledge and technique to the Mashburn. But you know no more what actual pressure you are running in the 30-06 than I do in the MSM (I know I don't). We assume safe pressure based on those indicators above.

I posted this thread in April 2010 asking about the comparison of both the Mash and the Wby.

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/3983494/1


I bought a 7mm Wby to find out FOR MYSELF what could be done with published data. I wanted to test it out and know for myself. I figured if the data didn't match up I could punch my rifle out to Mashburn.

So far, with published data, I am getting the speeds and to prove for myself and others here I'll be buying some Hornaday 175 grain bullets to test out. And, measure their bearing surface.

I'll be glad to ship those bullets/componets and rifle to BobNH and let him test it out. My cost. Otherwise Bob, shut your belligerent, arrogant, angry, mouth up.

I never, ever said "know" pressure... I said "extrapolate" pressure.

You're fixated on something I NEVER said...

So you bought a Wby to see for yourself. Don't own a Mashburn and never have and are mad because guys that have owned and loaded for both don't agree with you? Wow. That's interesting.

Not to pick on you exclusively, but no one else on here who is bad mouthing the Mashburn has loaded for one either.

I said you can't KNOW pressure in any cartridge as a conventional handloader and you said. And I quote. "Baloney". I'm sorry if I misinterpreted that.

Gotchya, fair enough.

No, I don't own a Mashburn and now after shooting the Weatherby I have no need to. That's my point, if the Wby didn't get advertised speeds I was going to go Mashburn.

So far, Those who own both have not shown up. You say loaded for your "brother". And yet you bring no load data?

Not out to offend you, but I think you're a boolshuuter.

Bring your load data to the table from all those 175's you've loaded for the Wby. Let's see it.

So if I'm tracking- a 7mm RM will be within 100 to 150 FPS of a 7mm RUM? And a 7mm Weatherby and STW virtually IS a 7mm RUM?

I'm here for answers folks...that's why I bought the rifle.

Where are all those "friends" and "brothers" that you speak of that are experienced loaders for the 7mm Weatherby?

John pretty well covered the "how" a page or two back...

Oh I get it. And I'm certainly not a hand loading guru, however when a cartridge is matching velocities of another that has nearly 20 grains more powder, either pressures aren't equal or you're having to play "56 trick moves" to get it. Which is exactly what it seems like Bob has been saying in this thread. I personally don't care either way- I don't own a 7mm RM anymore, have never owned a 7mm Weatherby, STW or RUM, and the only 7mm's I shoot on the regular are a 7-08 and a WSM, but something seems off with that.

Why don't you and Bob write or call Hornaday and tell them they are wrong.

I'll write and call them and tell them they are right. But then, I'm the one actually shooting their loads.

Facts were presented in this thread, but since those contradict preconceived notions, they "must" be wrong.

The engineers at SAAMI and the engineers at the component/ammo Co's obviously aren't all that bright...

Su 35 I have been out of town for a couple of days and want to bait you further.

Neither Bob nor I load our Mashburns so that the bullet extends below the neck. I filled a fired case from my #1 Mashburn with water Thursday night. It shows a case capacity to the bottom of the neck at 82.8 gr. So by your data I have 2.8 gr. +/- minus more case capacity than you.

Now in the real world 2.8 gr. is not much and probably results in maybe 25-30 fps. of velocity difference at a 65K max but it is still more case capacity. I get a chronoed. 3060 fps. from this 24" Mashburn with 74 gr. H1000 and Sierra 175's. I'm happy and intend to continue using this cartridge.

Flame on fellow!!!!!

Docbill, seems you have used both no? Years back i think it was you who did the case capacity comparison..which turns out the mashburn has 3 grains more than the wby?

Three [bleep] grains guys..thats what we are arguing about? As most know neither the mash or wby suffer from mag constraints. The MK5 is long, then theres the M700 like mine that are 3.6" right off the rack.

From reading here, the wby guys are the ones doing all the trick moves, but the wildcat shooters are keeping it simple..

This thread is a damn hoot.Grown men stomping there feet and holding their breath, insisting there toy is the best, incredible.

Tanner, yes..3rd season kicked my ass this year, shot this one the last day in dark azz pines, split second to decide, turned out to be a 3x4.

Docbill,

Thanks very much for that information. Now I can satisfy pathfinder76's request, and apply a basic internal ballistic formula to the 7mm Mashburn.

First, I found the water capacity of once-fired 7mm Remington Magnum (made by Federal), 7mm Weatherby (Weatherby factory, made by Norma) and 7mm STW brass (Remington). First I measured with the water level at the bottom of the necks, like Docbill did, when he found his Mashburn brass held 82.8 grains. Here are the results:

7mm STW--90.6 grains
7mm Rem--79.9 grains
7mm Wby--83.3 grains

It may seem strange that the 7mm Weatherby has slightly more powder room than the Mashburn, but that's with water to the bottom of the neck. I next measured the 7mm Weatherby capacity with a 175 Sierra GameKing seated to the SAAMI standard cartridge length, and got a water capacity of 80.7 grains. This is still very close to the Mashburn's, and is because the Norma/Weatherby brass is pretty light, weighing 20 grains less than the Federal 7mm Remington Magnum brass.

Then I applied the ballistic formula that any change in case capacity in the same caliber results in 1/4 that change in velocity, in loads of the same pressure. I came up with this formula years ago empirically, by crunching the numbers of published, pressure-tested data. The result of my empirical approach was confirmed a couple years later by the late Don Miller, the guy who created the rifling twist formula used in Bryan Litz�s book and ballistic program, and published an article about it in either Precision Shooter or Varmint Hunter, I forget which.

Many people aren�t aware of this ratio. Quite a few assume velocity is directly proportional to case capacity, or close to it. This can be easily disproved by comparing the .308 Winchester to the .300 RUM. The RUM has about 100 grains of powder space, and the .308 only about 50, but the .300 RUM does not get twice the velocity of the .308. Instead it gets about 25% more. (I�m not going to do the math for everybody.)

Following the 1/4 formula, we can figure that the 7mm Mashburn as described by Docbill will get 97.7% of the velocity of the 7mm STW. I used the 7mm STW because I had a fired case for measuring the powder room, and it has a SAAMI maximum pressure of 65,000 psi, as high as SAAMI standards are in any round.

If we look up the 7mm STW in various handloading data sources, we find the top velocity is usually around 3000 fps for 175-grain bullets. The Nosler manual lists 3042 fps from a 26� barrel, Hodgdon 3020 (24�), Hornady 3000 (26�), Norma 2989 (26�), and Alliant 3033 (24�). The highest with a 24� barrel like Docbill�s rifle is Alliant�s at 3033. Applying the formula we multiply 3033 x .977 and get 2963 fps.

This is about what the 7mm Mashburn should get at 65,000 psi or close to it. This isn�t surprising, since with bullets seated to the base of the neck the Mashburn only holds about three grains more powder than the 7mm Remington Magnum. Or at least it does with the cases Docbill and I measured. Changing the brand of brass would have an effect�in fact, using fire-formed Norma 7mm Weatherby Magnum brass would increase the capacity of the Mashburn somewhat, though the neck would be a little shorter than when using .300 Winchester brass, 2.55� versus 2.62�.

Pressure also varies depending on the bullet. The 175 Sierra Docbill uses will develop a little less pressure than many other 175�s because of the shorter bearing surface of boattail bullets, but his velocity of 3060 fps indicates the pressure probably is a little more than 65,000.

Using the old Homer Powley formula (again proven many times) that pressure increases twice as fast a velocity indicates a pressure of 69,000+ psi. This also isn�t surprising, since around 70,000 psi is about where most pressures end up when using �traditional� pressure signs such as bolt lift, primer pocket tightness, etc.

This isn�t exactly dangerous, obviously, but manufacturers of ammo and rifles prefer a little more safety margin, just in case a rifle is fired in very hot weather, or there�s dust or water in the bore, both of which can raise pressures. Handloaders using a wildcat that�s supposed to get more zip aren�t usually as concerned.

Thanks John for all the work. Just as a thought exercise, do you think the old Rem factory listing of 3050 fps. (if my memory is correct) for the 7 Rem. 175 load was over 65 K psi. or did they use majik powder to get those #'s. They have obviously turned the power down on that load now for several widely known reasons.

I use .300 Win Match Federal brass. I don't know if other brands are thicker or not. I develop all my loads in the Texas summer and usually the temps. are over 90 and at times over 100 so if it works in our temps then it should not be an issue. I also chose H1000 for its hopefully temp. stabality. In my other rifle I use RL-25 and also developed that load in the summer using Hornady 162's. I backed that load down to 3225 using 75 gr. The AOL on that load is a little longer than the other Mashburn.

Docbill,

Just for conversation's sake, QL estimates that 162 load of 75gr RL25 at 3226 fps and 75,833 psi peak pressure.

Docbill,

The original 7mm Remington Magnum factory loads were tested in 26" barrels--as were most cartridges in those days. They used what was later sold as IMR7828, but the testing as also done with copper crushers. When the industry later started the switch to piezo-electronic testing, it was found the pressures were very high--and the 7mm Remington Magnum's pressures also tended to vary more than many others rounds. Thus the eventual drop in factory ballistics.

The argument I have with the Mashburn guys is when they get all pissy that my 24" 3 groove .280AI is supposedly "greatly" over pressure because I get 3200 fps out of a 140 TTSX. Their basis is that the Barnes book shows that speed for a 26". Never mind that calls to Nosler and Barnes say its a perfectly safe load and gets its speed due to the 3 groove and less bearing on bullet thus less pressure/resistance.

I'm supposedly guessing yet the Mash burn loaders doing the same thing are relying on ancient pressure data.


Intellesting....

Docbill, thank you for providing your data, excellent.


I went into town today and found two boxes of Hornaday 7mm 175 grain bullets. RN and SP.

I then measured the bearing surface of all three bullets. Here is what I came up with. Probably not exact but very close.

Horn 175 SP was .730
Horn 175 RN was .800
Nosler 175 LRAB was .650 much less,

Then loaded them to exact Hornaday book data. Using Rem brass and Rem Mag primer. Hornaday uses a 26" barrel, mine is 24".

I also loaded some 175 LRAB to that data as well.
Here are my results and conclusion.

Hornaday 7mm 175 SP I loaded Hornadays recommended max load of RL25 75.9 grains
Velocity was 3,044 for average.

Hornaday 7mm 175 RN (same load)
Velocity was 2,989 for average.

Nosler 175mm LRAB (same load)
3,167 for average

My conclusion, I had it backwards. Less bearing surface resulted in higher speeds. This is I would think a good thing for shooting the high BC LRAB and higher speeds.

2" of more barrel and I would be right in line with Hornaday results shooting the Horn 175 SP at 3,100 fps.

Absolutely no signs of any pressure with the loads.




Here was my LRAB load. Am I out there pressure wise?
Unless someone shows me I am wrong...
I don't think so, seeing that the LRAB has less bearing surface.





I'll test the H4831 load next week.

And something the Mashburnites just hate to hear. Their cartridge doesn't really have all that pressure breathing space as they thought it had.

I would bet the Nosler 175 Partition at 3,050 is getting over 70K psi.

Thanks Mule Deer, the original Myth buster.

To bad Page and Hagel didn't have Mule Deer around.

If this was a court of law and the evidence presented today.
Bob would have his lawyer butt handed to him.

Page and Hagel didn't have the benefit of what our friend MD has available to him. They were men of their time and undoubtedly did the best they could.

But I'm biased that ole' JB might be the best gun writer to ever pick up a pen. Talk about a flexible and original thinker... I appreciate his input on this forum, and is frankly one of the few reasons I still hang around.

But arguing over Ballistic Gack is one of the most trivial things in life possible, certainly...

Are we gloating a little?

No doubt, but then Mashburnites were/are relying on that time period.

Not taking anything away from the Mashburn, still a great cartridge.



I really didn't appreciate the way Bob portrayed me.

JB, rates VERY highly with me, as well, and I started reading gun "lit", hidden in my text books at age 12, in 1958, when I started shooting. I have read all of the well known ones and many others whom were/are not as famous, although VERY talented....the late Ernie Stewart, of "BC Outdoors" was one such and "Bert" Stent, of central BC, active in my youth and before, was another.

I don't really see ANY writer, per se, as THE best, greatest and tend to evaluate specific articles, more than the individual(s), who wrote them. I agree with Brad, that Page and Hagel, I just, finally, purchased the last of his books for my enjoyment, were men of a time when the kinds of technological gizmos that we now have to measure various ballistic phenomena, were just not available.

I have simply enormous respect for Bob Hagel, always have had and he always impressed me with his honesty, knowledge and a certain humility that comes across in his written work. However, we live in a different world, in many important respects and should benefit from "progress" as much as we can.

All of this, notwithstanding, I will very simply reiterate my previous comments about "BobinNH" and will flatly state that he is one of the half dozen guys whom I have "met" on the gun-related internet, that I wish could accompany me on a hunt in northern BC....but, our laws exclude that possibility and my age ain't helping much, either!

So, what I get from all of this, is that, I really wish I could get a Simillion-built 7MSM, on a Dakota 76, for first choice, and see what it would do on "clearcut" Elk and Moose, here in BC, wearing a Swaro Z3 in 3x10x42, flinging 175s at, hopedully, 3000?

This, and I ain't even remotely a "wildcat" sort of guy!

Then, I wouldn't MIND one of those neat "UL" Weatherby's in 7mm Bee, either........

I'm not a fan of Weathebys but I sure think I could own one of those UL's!

Now, with a simple query and hoping for a peaceful reply(s).

IF, I had two identical actions, long enough in the mag boxes, identical barrels of 24" and both chambered in the optimal manner to obtain the best performances from each, one in 7mmBee and the other in 7mmMSM....

Which, freebore or not, loaded with 160 and 175 Nosler Pts, ONLY, would give the highest, SAFE velocities?

JB?

Others?

Almost as if someone at Nosler knew what they were doing when creating the LRAB...

Thanks JB, SU35 and Doc for the info and testing.

Mike

Thanks for the good words, guys. I must mention that both Hagel and Page were both large and positive influences on my eventual career.

What it looks like to me is the Weatherby and Mashburn are so close in case capacity that the only very small differences between them are the freebore of the Weatherby and brass price/availability. And after all the gack, probably the most practical of all the 7mm magnums is the Remington!

I have fooled with more than a couple 7mm Weatherby's and had to lean on things pretty hard to get to 3100fps with 160's. This was from 24" barreled rigs. And I have tried every powder under the sun pretty much.
I also found the Weatherby to be a little bitchy and honestly if I were going to fool with a fast 7mm again it would be a Mashburn, 7mm WSM, long throated 7mm rem mag, or perhaps a 7mm-338 remington ultra mag

Sound advice that I might have used had I not came to my senses and went to .30 cals.....

So if I claim 3000 to 3050 with 175's in the MSM I'm as stuffed as a Christmas turkey, but 3130 with the same weight of bullet in the Wby is as righteous as Mother Theresa? Please.

John, thanks for the info.

My current Mashburn used to wear a 7mm rem mag barrel. When the current barrel goes it will likely be a remington 7 again. Once a guy gets tipping over game he sees that holes in the right places make many cartridges indistinguishable in the field. The old 7mm Remington Magnum makes things simple. Most days I like simple. Especially in a hunting rifle. I guess that's why my other serious hunting rifle is a 30-06.

Well looks like I lose according to all the ballistic "theory" and interpolation on the Internet....but to boot strap a court case I'd have to hire qualified ballistics lab technician at a minimum( with appropriate degrees and experience),attach pressure equipment to several barrels and actually shoot one against the other....to be conclusive the sampling would have to be pretty large,given variations in bore/chamber dimensions,and other stuff,which we all know varies quite a bit.



In the end I don't have a 7 mm Weatherby;and a lot of naysayers on here don't have a Mashburns.Matter of fact,none of them do and those that have built them seem happy,even though it appears their pet is alleged to be running in excess of 70,000 psi to get their velocities.I don't know how much exposure to these loads it takes for primer pockets to open up but I guess time will tell.Seems we are all doing a lot of pressure "guessing" out there.

Like most on here I have to assume that the majority of us choose cartridges to attain a velocity level based on what we are seeing in loading manuals,or assume to be generally "true" when it comes to wildcats because the majority of us do not have a ballistic lab at our disposal.We also talk to others and go on our own "experience".

Mine with Weatherby cartridges in general has been good...I have owned several 300 Weatherby's and one 270 Weatherby magnums. Both delivered very high velocities with factory ammo;and I could not safely achieve the same velocities with my handoads. I also did not relish $2 bucks a piece for brass,did not like the Remington alternative and factory ammo running $50-$90 bucks a box did not appeal either.

Also in the back of my mind was general knowledge of situations such as Dave 7mm posted of....standard throats in Weatherby chambered rifles, without free bore,causing problems with factory ammo.

Plus , I looked at data other than Weatherby's and Hornady's and saw things like the Speer data that shows 68-H4831- with their 175 gr bullet giving 2848 fps...and other bullets showing a high of 2982 with the same bullets.Ditto the SAAMI data..If you look at enough data you will not see many showing materially over 3000 fps with a 175 gr bullet.

Plus, there is that "freebore"...which I most certainly did not want,since I have done more than my share of playing with 7mm barrels and throats of varying dimensions throating,,rifling, twist and other stuff, I came to the conclusions that getting a little more case capacity was a better way to go than trying to achieve this with barrel tricks....experience taught me this. And based on a lot of loading and shooting with a 7 Rem Mag,an STW,7mm WSM,and Dakota, I did not regard the 7mm Weatherby as suited to the purpose I was after....still don't.

I don't recall ever saying that a 7mm Mashburn had a LOT more capacity than a 7mm Rem Mag or Weatherby magnum,and eve the Mashburn people have acknowledged that.

But to do what I wanted I thought that I did not NEED a lot more.....I needed a skosh more,ad a longer neck....So no Rosco I am not arguing over 3 grains of net capacity.And even guys like Bob Hagel with their old school methods said the same things about the Mashburn vs the Weatherby...those reading his stuff about the cartridge would know that.

My goals were simple...a 175 gr bullet at 3050 or so,and a 160 gr at 3150....comfortably and without the ragged edge feeling that I often had running a 7 Rem Mag pretty hard. I ended up with the Mashburn. I could have anything I wanted.I was not under any illusions about it being the fastest 7mm magnum around and have said that many times but apparently this has failed to get through to some pretty thick skulls.

I can't recall them all but I did look at a lot of data like that in the Speer manual that says they developed their 7mm Weatherby data at 65,000 psi and showed a high of 2982 fps with a 175 gr bullet;and 68-H4831-175 at 2854 fps....about what the SAMMI data shows at 65,000 psi.Sierra ,Hodgdon and Barnes data are equally unimpressive. Nosler shows 4-5 loads at a bit over 3000 fps for the 7mm Weatherby,and Hornady shows their "lines" and generic velocity levels at 3100 fps,but I did not trust it completely when balanced against the other data,since I am not one to cherry pick data, and try to look at as many sources as possible.

In looking around I also noticed, that moving a 175 gr 7mm bullet reliably over 3000 fps is tough to do even in cartridges like an STW and a 7mmRUM. I don't think anyone will argue that both have substantially more capacity than a 7mm Weatherby.

So, if I were making the choice again,the 7mm Weatherby would still not be in the running;certainly not for the purpose of starting a 175 gr 7mm bullet at over 3100 fps,not withstanding all the arguments to the contrary posted here.

If I attached a strain gauge to a Mashburn and discovered that my load of 73 gr H1000 for 3075;or 75 gr with a 160 for 3180 was actually getting a pressure reading of over 70,000 psi as Brad suggests, I'd drop the cartridge like a hot potato,and admit I got fooled...... But in re barreling I still would not pick the 7mm Weatherby for the task,recognizing that I did not choose quite enough case volume for the task.I try hard not to get emotional about cartridges.

SU35 it's interesting that you did the bearing surface test with the ABLR after you decided to substitute a 175 gr Nosler bullet for 160 gr data per the Nosler Manual,and then used the Hornady data to substantiate it.I am guessing tha,either you did not see the Nosler data,or you simply chose to ignore it.

It also occurred to me that ..."maybe he is getting away with it because these high BC bullets have less bearing surfaces than many conventional bullets".......plus the fact that I measured a couple of Nosler bullet last week for diameter and they were all a thou undersized,compared to the Kodiak bonded bullets I also measured. (Charges were dropped a grain to test the Kodiaks in view of that).In any event I learned awhile back not to work up tj Hornady data max loads and then substitute other maker' bullets....whether this applies across the board with all Hornady bullets and loads I have no idea.But I do try to be careful.

I am no products liability lawyer; but if your rifle had blown up in your face from the effects of all this experimenting, I am afraid you would be pretty much SOL.

At first blush,your lawyer would likely join Remington(rifle and cases(?), Weatherby,Nosler,Hornady,Hodgdon,etc as party defendants to the action.

I am certain that the insurance company lawyers would all look at the fact that you ignored the data in the Nosler Manual, arguing that 70.5 grains of H4831 is a maximum load for the 160 gr bullet and that loading a 175 gr in lieu thereof is tantamount to contributory negligence resulting in your injury,ie, that you contributed materially to your own damages....plus the fact that I am unaware of their data showing any H4831 loads for a 175 gr ABLR.

Your chronograph readings of 3160+ fps with a 175 gr ABLR would be more evidence of reckless conduct,since those velocities are not shown anywhere that I am aware of for the 7mm Weatherby Magnum...certainly not in Nosler's manual..

I expect they would be dismissed as party defendants on a Motion For Summary Judgement unless another hook could be found to keep them in for a trial on the merits.Maybe they would pay a small settlement to avoid the hassle of having to go to trial.

In any event,if I were one of the insurance company lawyers, I would have field day with you. Besides that,after bearing witness to your conduct,I doubt any lawyer would take your case on a contingent basis.

This would not be like a car accident you know


I am afraid that none of the stuff posted by others on here would save your bacon.You may take cold comfort in it all in this kangaroo jurisdiction,but I can assure you none of the information and advise posted here would help you much, if any at all in a Courtroom,given your conduct.

I am not certain of the educational backgrounds of everybody who has chosen to participate in this little slug fest,but doubt they would be qualified as an expert witness due to lack of technical education in the specific field.If I am mistaken the comment is withdrawn.

An old now deceased pal of mine testified in many gun related cases but he had engineering degrees,and was a very experienced guy in a number of shooting endeavors.

So I would not bet any serious money on me getting my "lawyer butt kicked"...if I were you I would refrain from handing out any advise on two things....the law, and based on what I have seen here, handloading.



And on sending the rifle to me,I think I will pass....your derogatory remarks about me made it "personal",and I don't want responsibility for your gear....if I want to mess with a 7mm Weatherby I can buy one,thanks. Besides a sample of "one" would not prove very much if anything at all.

If you're going to argue your case, you have to have the facts right. Nowhere did I say or suggest the above, unless there's another Brad on this thread I'm not aware of...

pathfinder76,

It's hard to beat the tried and true, isn't it?

I've had several 7mm RM's, but ended up with my latest at a steal a few months ago. It's a custom rifle based on a 1909 Argentine action with a very nice piece of classis-styled fiddleback walnut. It's nicely done but lacks checkering--which I can do myself. There's no markings about who did either the metal or wood work, so I suspect it just never got finished, for one reason or another. But I'm pretty good st checkering, and can finish it this winter.

i wonder why my 27 in brux barreled 7-300 win mag wont break 3000 with a 178 lrab with any powder before showing pressure signs, bright ejector mark,,,

If your 300 Win cases had double radius shoulders, you'd be there easy....

Tanner

Interesting.

I've seen "bright ejector marks" on so many factory ammo case heads I pretty much ignore that as a real indicator.

Obviously you're looking at other indicators too.

But, as has been stated so often, "traditional indicators" often tell more about a chamber or brass quality than pressure.

But you sound like a careful handloader, not pressing the envelope and your tribe should be applauded!

If you are getting good case life and no indications of high pressure, except an arbitrary number on a strain gauge, why would you drop your wildcat?

The .257 Weatherby Magnum appeared early in the Weatherby line and became a favorite of Roy Weatherby. Roy, born in 1910 to a Kansas sharecropper, got into the gun business almost by accident. Keen to pull himself from his family's poverty, he clerked in a music store and sold washing machines. He married Camilla Jackson in 1936. The couple landed in San Diego, California, where Roy made a good living ($200 a month) selling insurance.

Roy indulged an interest in rifles by designing high-velocity rounds on the .300 Holland case. Weatherby's signature "double radius" shoulder (and early success) owes much to California wildcatter R.W. Miller. In 1940 Miller was experimenting with the .300 Hoffman, dropped by Western Cartridge Co. seven years earlier. Miller replaced the angular junctures at neck and shoulder with rounded corners for smooth gas flow. American Rifleman sent authority E. Baden Powell for a look. Powell advised Miller to straighten the case body. Result: the Powell Miller Venturi Freebore. In 1944 the men went into business as Vard, Inc., then sold out in 1945 to Hollywood Tool & Die.

About then, Roy carried a .270 PMVF on a deer hunt and liked it. However, Miller wouldn't help Roy design that radius into his cases. Machinist George Fuller agreed to provide the tooling. A full-length version of Roy's modified .300 H&H became the .300 Weatherby, but his first magnums were shorter and necked to .257, .277 and .284. In 1985, Roy recalled that the .257 arrived "sometime in 1944."

In 1946 he pledged "everything [he] owned" to get a $5,000 business loan. His future brightened the day Gary Cooper walked into his retail shop. The two men (both car buffs) hit it off, and Cooper became a regular visitor, introducing Roy to other Hollywood stars. A cash infusion from Texas oilman Herb Klein lifted Weatherby's fortunes, as the .257 and its fast-stepping siblings impressed customers with flat flight and a deadly punch.

"Roy made a good living ($200 a month) selling insurance."

Almost as good as Leupold usuing real diamonds.....


dave

How sad.....I will never reach the status of camp councilor on the fire, but I would suggest this thread has reached it's useful purpose. Aren't there leaves to rake, or snow to shovel, or a good football game on?

I say "to each his own".

This has become just a d..k flexing contest over what....60 fps? If you enjoy your Weatherby or your Mashburn so be it. Knock yourself out!

After reading this thread, I find it interesting why anyone would ask why I like the 280AI.

"To each his own"

This raises a whole different point. It seems that at 70k traditional pressure signs appear, which is about 8% higher pressure than 65k some factory rounds are loaded to.If you are not seeing any signs and brass life is acceptable why not just roll with it?
I might add that I belive the 338 Lapua is loaded to around 70k and its chambered in the Remington 700, weatherby mark 5, cz550 and I am sure others.

The SAAMI maximum average pressure for the .338 Lapua is 65,000 psi, exactly the same as the .270 Winchester, 7mm Weatherby Magnum, 7mm STW, .300 WSM and a host of others. It's the highest average pressure they allow.

You can find all the SAAMI specs online at www.saami.org.

7mm Wby. Mag.

Introduced nearly 20 years before the popular 7mm Remington Mag., the Weatherby� version gives non-handloaders handloaded 7mm magnum performance. Delivers 400 fps more velocity than the 7mm Mauser. Ballistically similar to the .270 Weatherby� Magnum with a larger selection of bullet weights, this cartridge is well-suited for any North American game as well as thin-skinned African game.

7mm Weatherby Magnum is available in Mark V� models: Ultra Lightweight, Accumark, Accumark RC, Deluxe, Lazermark, Sporter, Fibermark Composite and Euromark.

20 cartridges per box.

This product is not eligible for overnight or 2-day shipping.
$67.00



Caliber Weight Grains Bullet Type Suggested Usage B/C Price
7mm Wby. 120 Barnes TTSX M .373 $90.00 Out of stock
7mm Wby. 139 SP M .392 $67.00 Out of stock
7mm Wby. 140 Barnes TSX M .477 $90.00 Out of stock
7mm Wby. 150 BST M .493 $78.00 Out of stock
7mm Wby. 154 SP M .433 $67.00 Out of stock
7mm Wby. 160 Accubond M .531 $90.00 Out of stock
7mm Wby. 160 Partition M .475 $90.00 Out of stock
7mm Wby. 175 SP MB .462 $67.00 Out of stock

USAGE: V - Varmint; M - Medium Game (Deer, Sheep, Pronghorn, Black Bear); B - Big Game (Elk, Moose, Grizzly); A - African Big Game (Elephant, Cape Buffalo, Rhino, Lion)
BULLET TYPE: SP - Spire Point; Rn-EX - Round Nose-Expanding; FMJ - Full Metal Jacket; Barnes TSX - Barnes� TSX�; Barnes TTSX - Barnes� TTSX�; Partition - Nosler� Partition� Flat Base; BST - Nosler� Ballistic Tip�; Accubond - Nosler� Accubond�; Spitzer - Norma� Spitzer


Even Weathbery ammo is out of stock...


dave

Bob, yeah, keep on guessing, you have a penchant for it. I saw that Hornaday had included their round nose 175 for their data,I knew that bullet like most RN's are long on surface. That was enough for me to know to proceed. You keep trying pick nits that don't exist.

I started off with Rem cases and Rem primers and saw that the case capacity of Federal was pretty much the same. So to belabor the point for you. I knew I could proceed to Fed cases.

I could care less what Speer data says. I don't shoot their bullets. Why are they even in this conversation?



Like a typical lawyer Bob, you don't have the data and evidence so you go after the witness. Something you have done continually in this thread towards me. I didn't appreciate your derogatory remarks, So, if anything you need to look at your own conduct and behavior. Your anger was glaring and your words were not nice.




Bob you are not me, I have not given any law advise. Also, you should take your own advise for somebody who shoots a wildcat and guesses a lot.

Be responsible for your own actions Bob. So far, your blame shifting is not working.


I shot Hornaday data and substituted one bullet that I knew was going to work by seeing its bearing surface.

I've been loading for over 40 years Bob. Yes, I am still learning and learned a lot from JB the past few days.

I learned that I would not be shooting your load in a Mashburn.

Where this train ran off the tracks.

Yes, but I believe this was changed at some point. I think initially CIP or SAAMI had it rated at 68k and change.

4700 BAR converts to 68167.736733202 psi

Where it ran off the tracks for me.






He didn't have the evidence, he was assuming and guessing and accusing, so in typical lawyer fashion did his best to discredit the witness.

I used the Hornaday load data sir. It worked as shown. I went by the book.

So far the Bee has been sweet and easy to use.

How have you found it on game?

OK.

So a 175 gr bullet at 3160 from a 7mm Weatherby Magnum is OK...but 3050 from a Mashburn is not...I see.That's interesting.


OK we won't talk about the Speer Manual, except to say it does not show as much velocity as is claimed on here for the 7mm Weatherby and 175's.

That said,I don't have a 7mm Weatherby so maybe you guys can answer something, because I am confused about the case capacity business.

The Nosler Manual shows that the following loads for the 7MM Weatherby are "compressed":

79.5 gr Retumbo and 160's 103% density.

76 gr RL25 with 160 (102% density.

78 Retumbo 175 gr 103% density.

I know for certain (without guessing) that at least the 76 gr RL25 load is not close to compression in the Mashburn.

Can you 7mm Weatherby folks let me know if this is true?

I also note from the Nosler data that a load of 74 H1000-175 is at 97% density in the Weatherby. It is not close to 97% of filling the case with the Mashburn.

Can you guys help me understand this in light of the Weatherby having more capacity??

Agreed. It would seem that mature men ought to be able to have a discussion without resorting to the ridiculous.

All this over 2 or 3 grains of capacity???????

Does anyone make 7Bee brass besides Norma? If so, what is going to happen when the case capacity of thicker/heavier brass is actually quite a bit lower than Norma?


Why not form some 7Bee brass into Mashburn size so that we can know what the case capacity would be if we compared apples-to-apples. Then the Mashburn might shine again.

I'd really like to see what a Mashburn can do loaded to 65k, if formed with thin Norma brass and given equal freebore to a Bee. Wouldn't we see another 100-200 safe fps?

No, we wouldn't. The case capacity is too similar between the Weatherby and Mashburn to get even close to another 100 fps at the same pressures.

I just measured water capacity of a fired Mashburn case at 84.4 grains to the base of the neck.

Well that is interesting! I'll double check my scale tonight. Maybe I miss read the blasted scale.

Perusing my old Hodgdon Manual, a 24" 7mm Wby gets 3,022 with 74.7 of H1000 under a 175 Hdy SP @ 54,000 CUP. It's their only load that breaks 3,000 fps.

My bet is the Mashburn will break 3,000 easier with more than one powder.

All this is splitting hairs and I can see the arguments for either/or.

But to disregard what the Wby Freebore is accomplishing is a bit silly.

Yes, and the 30-338 Lapua still has a CIP rating of 4700 Bar.

30-338 only exists as a wildcat at this time, so no CIP or SAAMI standard

I am just telling you what I found over the years with multiple 24" barreled 7mm Weatherby's.
I would say over 3100fps with 175gr bullets, at a safe pressure is a pipe dream with a 7mm weatherby and a normal length barrel, regardless of what a manual says.
Besides, are manuals really more than a very basic guideline? Heck, I have done the same thing as you and cherry picked Hornaday data and then substituted a 180gr Barnes TTSX bullets in my 24" barreled 300 Ultra and got 3400fps out of a below max load. Brass life was decent in that I reloaded some three times, accuracy was good, and no traditional pressure signs. Does this mean the load was at or below 65k PSI? I think not and there is no mystery where the velocity came from.

.300 lapua mag isn't saami'd?

It was standardized by CIP and I should have referred to it as above instead of saying 30-338 Lapua.

http://www.lapua.com/en/story-of--338-lapua-magnum.html

No factory rifles have ever been built in 30-338 Lapua, not that the cartridge has been CIP'd

Yes, but it was standardized by CIP, even though no rifles were commercially chambered in it.

It says a small run were built for CIP. I asked the question, knowing the answer, pretty conclusively, but not positive. I know that the pressures were lowered for the 338, but not the 300 lapua.

I run a 7mm-338LM and a 300 lapua improved and 338LM. I love that 338LM lapua brass, great stuff, just hate the large boltface. Oh how I wish Lapua would make some RUM brass.

If read what I posted from Laupa;s web site above it does not mention that the 300 was ever CIP'd

Yes it does.
"Both the 300 and 338 Lapua Magnums were formally approved by CIP in 1989."

Okay, so basically what I'm understanding is that the 7Bee and 7MSM are nearly the same thing in case capacity, with the advantage ever so slightly to the Mashburn.

However, the 7Bee is built with freebore which gives a little bit of free lunch so that they end up virtually even in their ballistics.

Could I use a NECO or Tubbs kit to push the throat forward enough in a standard 7RemMag to get the benefits of "freebore"?

Missed it

Nothing like starting the rifling half way down the barrel to lower pressure.
dave

Yep,
Or you could just shoot out a rifle with a normal freebore.
After its career is over as a normal shooting rifle and the throat is wore out.
You could hot up the loads and pretend its a Weatherby.
dave

NOt a big mystery there,are you seating your bullets at 3.350" like they are in the book?

FWIW my LRX is seated at 3.535 and the VLD seems to like 3.450..Not compressed with 76 grains.

And for the record I dont claim that the wby has more capacity..nor do I think i'll see 3100 with the 175's out of mine. But I'll report back sometime next week with what I see.

Bob, You shoot a 175 Partition. I shoot a LRAB. Two different bullets and bearing surfaces. Two differ speeds.


Bob, it all comes down to this.

I used Hornaday Load data and swaped out bullets with one that I saw had a shorter bearing surface. It worked.
I also shot Hornady bullets using their data. It worked too.


You are making a big deal out of nothing and trying to pick nits that are not there.



My apologies for my response in mistaking the intent of your post. I was out of order.


I'm done with this thread.

Bob, I dont use RL25 in my 7wby so you had me wondering. I dumped in 79 grains of '25, and it hasnt started to come up the neck yet, but i suspect you wouldt get much of a "shake" of powder if I were to seat at my VLD depth, possibly lightly compressed.

Kinda hard to tell exactly how far the powder comes up, but here is a pic of the 79 grains of '25

It's a fact it works... not a fact it's an intelligent design.
There's a difference.

I've shot a number of Weatherby factory rifles made in the past decade, and all shot better than the average factory rifle, and most shot VERY well. Maybe not accurately enough to satisfy those who always shoot custom-barreled rifles, but my first was a Vanguard .2657 Weatherby that would shoot 3-shot groups in the 1/2 MOA range out to 500 with more than one handload.

Have also had a couple of custom rifles in Weatherby chamberings where the maker insisted on a custom reamer without the freebore. They shot very well too--but not any better than the more accurate Weatherby factory rifles.

Bloody good one, "young Viking"!!!!

Just as a thought.
I've played some with GS Custom HV bullets.
If you look at the HV bullet,they have driving bands.
The first driving band is way back from what would be the conventional contact point for a normal shaped bullet.
A Weatherby on the bullet if you will,with a normal free bore.

dave

pathfinder76,

Wow! That's a big difference from what docbill measured, almost 2 whole grains! What does that come from--different brass, a difference in guessing where the base of the neck is, or (gasp!) different CHAMBERS in wildcat rifles?

I have tried to add some basic ballistic facts to this thread, but it continues to whirl even farther off the edge of the earth.

I'm going hunting whitetails tomorrow and will be gone for a few days. Hopefully there won't be anybody in camp who wants to argue about the case capacity, SAAMI versus CIP, or whether 100 fps makes a fat lot of difference in any 7mm magnum. Even more hopefully, when I come back somebody with a .338 Lapua will have shot this thread dead. Apparently nothing less will do the job.

My chamber was cut with a Hendrickson reamer.

I was using Winchester brass and am not sure how anyone tells where the base of the neck is. I tried all kinds of lights etc and in the end I stuck the case in my case trimmer and took the neck completely off and filled it full. That way I know I didn't have any extra water in there. :-)

Thanks Rosco that helps.

I don't doubt it John.

My best friend owned 3 custom Wbys (w/ freebore) both the 257 and 340 Wby's shot 1/2" moa. The 416 Wby shot sub 1", but it was a sub 8lb rifle so who really knows what it was capable of!

Chrono'd the 340 Wby 250 grain factory stuff in the 340 Wby.. it went 3,030 fps in a 26" bbl.

Brad,

I had two .340's. Back then the factory claimed 3,025 feet per second. Over the years when I have chrono loads for guys at the range, the only factory load which consistently hit published data was Weatherby.

Makes sense to me Weatherby is the only one with a vested interest in achieving the higher velocities! Why would Remchesteral risk it or purposely use thinner lighter brass.

Mike

Nothing at all wrong with Weatherby cartridges IME...the 270,300 and 340 have all delivered the velocities in factory ammo IME.The 340 is very accurate,free bore notwithstanding.

Chasing those velocities with handloads can sometimes be a chore,though...or at least push you to places you might not feel comfortable going,in some rifles. Maybe they use custom blends of powder not available to us in factory ammo....don't know.

I think they are best left to Weatherby rifles myself. They seem to have the ammo formulas worked out to sync with the rifles themselves. I would not spend long green for a custom chambered to one again....BTDT....., but many have with good results.

Custom makers like Darcy Echols and Gene Simillion do chamber for them....but without the freebore which basically wildcats them,and excludes the use of factory ammo..

Dang! I was reading this as I was eating lunch, so I was only paying about half attention, but I got all excited when I thought I was reading about another hot 6.5 to play with...

Perhaps I missed it earlier, where are the LR accubonds coming from? Powdervalley and the like have dredged up nothing

got mine at a local sportsman's warehouse.

I think I read where the DHS ordered about a million LR Accubonds.

Me either. But, I wanted one or two.

I give up. What's the difference?

Faux pa maybe? Don't know.don't care.

May be so. But, I think we all lose sleep over it.

I have now read this entire thread.

One thing I learned: Milk of Magnesia is only 2 or 3 grains more palatable than eating chalk.

but tastes about the same

After all the gack that has flowed here is it safe to posit the idea of a:

.300 Winny case necked to 7mm with the 40 degree Ackley shoulder wearing a barrel with the Weatherby freebore.

It should provide the best of all worlds.

or just build a STW and beat both..

But a 257 Weatherby kicks it all in the nuts...........


w

How does one create the freebore?

Just freebore a 7RemMag and you're there it would seem.

I had my smith bore my mashburn out so that the 160 grain accubond is seated even with the base of the neck. 3.67 if I recall correctly. This length just barely fits the magazine box. Are there any other long bullets that you think would work in a mashburn that is throated this long.

It is an interesting concept. Same bullet. Bore. Powder cap in the 98% range. Just scratch a bit more metal and you have nirvana... Huh...


W

7mm Rogue?

This was an interesting read. Never realized some of you were so deeply inflicted.

If you have a rifle that needs freebore, just shoot it a lot.

Here is something I'll add.

After shooting a couple of deer with the 145 LRX in the Mashburn I'm bored. So I loaded up some 150 Ballistic tips and went to the range. Low and behold with 73 grains of IMR 7828 I'm getting nice triangular 1/2" groups at 3151 fps. Drat that is way to slow. Or is it? Trajectory is within an inch to an inch and a half of that 145 LRX load at 3250 out to 500 yds. Big deal. So now I have a load that I know is breathing easy. Easier than any 7mm Rem Mag and it's in a better case design to boot.

You mean you havent seen any of the peekie weirdness that 7mm mags are noted for and your not shooting a rifle thats pre shot out from the factory usuing ammo that costs 120.00 a box??
dave

Gee's another tastes great less filling thread!

I'm glad this wound down!!

I actually like these threads.

This is how you learn things, even if it's minutiae. The only thing in this thread I'm thankful for is that with multiple Weatherby rifles and chamberings I've only had one that shot bad and it is a Winchester M70 of all things in .300.

Maybe if it was a 7 in M700 I wouldn't have that problem.

I've learned a lot about internal ballistics that I never knew. Threads like this are great if people stay civil and discuss matters.

3-4g

the difference between a 7RM and a 7WB
the difference betwixt a 7WB and Mashburn

Imagine what that same 3-4g capacity increase could do in the smaller 280 case.....:)

I guess you don't have to imagine it if you have a Nosler book...have a 7RM and a 7WB throated same with Nosler 140BTs, both with Douglas SS tubes. Have never owned a real WB but the advantage for these two goes to the WB.

In my Remington factory 7 Mag, 66g of IMR 4350, Rem case, 9 1/2 primer velocity on a 140g Accubond is 3250, with tiny groups. I don't have pressure issues on this load either.

Interesting stuff.

The 150 Ballistic Tip has proven to be very accurate in my factory 24" 7 Rem Mag also.

63 grs of H4350 gives me just over 3100 avg.

And a 160 Accubond pushed with 70 grs of Rel 25 has the same point of impact at 327 yards.

I haven't chronyed this load yet.

Hey Keith:
Did you put a dozen on the pole this year?

I may have missed it, but did you ever do any more confirmation of the BC's?

Good question Smoke,

I saw where scenar said the claimed BC for 129 Gr. 6.5 came up well short in the testing he did.

Just as to my own data, I recently shot several 7mm Wby rounds out of my Wby Ultralight Weight through my ProChrono, and I fell in love again with CorBon:

7MM WBY: Nosler Custom 160gr AB (26� barrel) (mfr: 3050 fps)
2,911 fps
2,936 fps
2,917 fps
2,943 fps
2,930 fps
2,936 fps
2,931 fps
AVG: 2,929 fps
FPE: 3,048 ft-lbs

7MM WBY: Weatherby 160gr AB (26� barrel) (mfr: 3050 fps)
2917 fps
2962 fps
2930 fps
AVG: 2,936 fps
FPE: 3,063 ft-lbs

7MM WBY: Weatherby 140gr TSX (26� barrel) (mfr: 3250 fps)
3079 fps
3137 fps
3167 fps
3182 fps
AVG: 3,141 fps
FPE: 3,067 ft-lbs

7MM WBY � CORBON 160gr TSX (26� barrel) (mfr: 3200 fps)
3,252 fps
3,228 fps
3,244 fps
3,228 fps
AVG: 3,238 fps
FPE: 3,725 ft-lbs

This is consistent with my chrono�s reception of CorBon .340 Wby rounds:

.340 WBY: CorBon 225gr TTSX (26� barrel) (mfr: 3100 fps)
3159 fps
3161 fps
3149 fps
3182 fps

CB is the only ammo I have found that consistently shoots above the specs. The Nosler Ammo in 7mm Wby, .340 Wby, and .375 Wby is however very consistent and accurate.

Just wanted to add,-

I knew JB was a smart fella but damn... I've learned a lot from this thread.

I also respect the heck out of Bob's opinion on just about anything and can certainly see both sides of the issue.

The info in this thread is what makes this place worth visiting and I'm glad we have folks like John & Bob.

what they know about rifles & cartridges would take a lifetime to learn and I'm way too lazy, so it's nice to cheat off 'em.

Maybe SU will see this and chime back in......

Rembo:

"Interesting stuff.

The 150 Ballistic Tip has proven to be very accurate in my factory 24" 7 Rem Mag also.

63 grs of H4350 gives me just over 3100 avg.

And a 160 Accubond pushed with 70 grs of Rel 25 has the same point of impact at 327 yards.

I haven't chronyed this load yet"

Typical loads for most of the Rem 700's that I have owned. The Win mag primer with the R#25 shrunk the groups to less than 1/2", velocity is shocking, primer pockets in Rem brass don't last long.

The BC's work spot on for me and I just tested them out to 1,200 yds.

Thanks. You didn't by chance test the 7 mm 150's, did you?

G1 or G7? Thanks!

G1

Have not developed the 150's yet.

Gotcha, thanks!