Home Forums Hunting & Shooting Custom Rifles & Wildcats 7MM Mashburn Super ????????

I know Dober has one of these, and killed that super elk. I also know it is a forerunner of the modern 7MM Mags. So what is the rest of the skinny on this caliber? What's the parent case?

For a real history find Bob Hagels article in Handloader/Rifle. It is in the big compendium book also. I make my cases from .300 Win Mag; original parent was .300 H&H. Neck down and move the shoulder back then fire form. Total case capacity is about 90 grains of water with a long neck that lets you keep .02 clearance off the lands while changing between 150, 160, and 175's. From what I can tell it has about ideal case capacity for a 7 mm hole. Very similar to the 7 mm Dakota without the availabilty problems and what the 7 Rem should have been.

If you build one make sure it is throated for an OAL of about 3.56" so you get all the case capacity. With 175's and RL-25, IMR 7828, or Retumbo you should be able to turn 3050 +/- with safe pressures in a 24" tube. Over 3200 fps with a 160.

In reality it is a .30 mag without the recoil or weight. Mine weighs 7.5 lbs. all up with a #3 Shilen tube. If you can't kill anything short of Cape Buffalo, Rhino, and Elephant with a 7 mm 175 at 3050 fps then we all need to stop hunting.

Warren Page was the master with this cartridge. He killed something north of 450 animals with his.

doc - whats the difference between the Mash Super and the current 7 STW?

I've been considering an STW for quite some time. I really dig the 7RM, I wonder what the STW/Mashburn does better than the 7RM.

b:Both the STW and the Mashburn are slightly faster than the 7RM.IIRC Page used 71 or 72 gr of H4831 with the 175 Nosler Partition for everything.It was chronographed by Remington back then at 3050 from a 22" barrel.The 160 gave 3150 from the same barrel.

In Handbook for shooters and Reloader's by Parker O. Ackley
page 407 he states that it is the same case as the 270 and 6.5
Super Mashburn. Description of 6.5 is made by necking down and shorting 300 H & H cases to 2.630 and is very similar to the 6.5
Apex. Hope that helps Cheers NC

I believe Jarrett has a similar "cat" on the 300 Win case. He has some data but no load info.

4 some reason or another I think...I have some load info...

Dober

Even with current powders, you get next to no increase in performance with the STW. You need to make the BIG jump to RUM to get much bump in performance. I have friends who have problems with STW's. Theirs are finiky to load for.

My Mashburn does not seem to have the intermittant pressure problems you hear about with 7 Rems. If you chamber a 7 Rem so that the base of a 175 is at the base of the neck and chamber the Mashburn the same, the difference in useable case capacity difference is only about 3-4 grains given the same target pressure and using the same powders. My preference is RL-25. So throated, the 7 Rem you will have freebore with all lesser weight bullets.

The Mashburn, Weatherby, and Rem are all performance similar. The Mashburn has a longer neck than the Rem and no designed in freebore. In a pinch if I end up somewhere without ammo, I can shoot 7 Rem in it and make it work. Not recommended but doable.

The 7 Rem is currently under loaded from the factory compared to original loadings to about 58 K psi. because of gun variability, short neck, and the design to fit a 30-06 action that forces bullets back in the case and reduces powder capacity by up to 20 gr compared to a long loaded Mashburn (col. +/- 3.56"). The Mashburn is what the Rem and Weatherby should have been.

docbill...I don`t think you ment 20grns?? Two maybe?
I like my 7 Wby on the 700 action..long enough to not hinder bullet seating depth.
The Wby chambering does have a free-bore, 1-9.5 twist barrel, which I have found in this particular rifle at least, has no ill effects on accuracy.
I don`t believe I`ve reached the limit in velocity yet either..Still learning what this cartridge can do.
Very impressed with accuracy!!

I'll have to check my data. My memory may have slipped on case capacity difference. Loaded length max to fit a 06 length is about 3.35 or so vs my setup at 3.562.

My Mashburn consistantly turns .6" with 162 Hornady Interlocks, Sierras, and NP's at about 3250+/-.

Wow..3250fps..with 160s`.

I`m shooting 168JLKs at about 3k. I say that because I cronied the load, 69grn 7828 at 2950fps. I moved up to 70 grns, and not cronied at that weight.

Just got some 160grn Accubonds I will be working with soon. After deer season..

The load is 76 gr. RL-25 and it is clocked. Air temp. was >100 F, so I'm not worried about pressure rise at high temp although neither gun nor ammo sat in the sun.

A recent Hornady manual shows 76 gr RL-25 for a 175 gr. in the 7 Roy at 3100 fps. I certainly wouldn't go any faster with either bullet weight. The Roy has freebore and the Mashburn has 3-4 gr. more effective case capacity. I view that as a swap in the load interpelation/work up process.

The 7Wea and 7RM have almost identical case capacity - the Roy has freebore. The fastest I've moved 175's is 2950 from current 26" 7RM with several powders. I'd consider some mods to get 3100 from a 175..............

Mark - what do you get from Ole' Betsy with 160's and 175's?

Find the article by Bob Hagel in the big compendum publication published by Wolfe Publication. It describes the Mashburn and its limitations. After that you, your loading manual, and your chronigraph are your friends. Call Hornady for details on the 7 Roy loads.

I haven`t gotten to 175s` yet...thinking bout 180 JLKs or Burgers.
These 7s really shine..

Where is a good place to get a 7mm Mashburn chamber cut?

What do you make the brass from?

You might check with Berger et.al. and see what they recommend for twist rates on their bullets. They might be too long to stabilize.

3100 +/- fps. in your Rem is just about the limit even loaded long. The old Rem factory data showed 3050 in a 26 in. barrel. The 3-4 grains difference in the Mashburn is probably worth 50-75 fps. max. not including individual variation. All 3 cart. are 3050 +/- fps. guns with 175's.

Warren Page did it all with one of these using a 22 " barrel and 3050 fps. from that barrel (Rem factory chroned)! That's why I think with modern powders and a 26" barrel 3100 is doable.

hey doc - not sure exactly what the big Wolfe compendum publication is. Could you please elaborate a bit?

You may be correct on the twist, tho I`ve found with target type bullets one can often squeek by using what could be marginal twist because of how the bullet is constructed..weight in the rear, nose hollow.
I think Berger reccomends 9. Yea, 9, so does Swampy with the 180s`
175s shoot well? Whats the twist rate in your rifle?

can't recall what the twist is of my 7 Mashburn tube, this is my 3rd one and they've all been the same but can't recall...

I couldn't get Bergers to shoot in this barrel but then again I've yet to get them to perk in any of the cals that I run....?

With the 175's I run R25 and with my 25" barrel I can push them to 3100, but prefer to run them a bit less. 3K-3050 seems a bit better to me in this barrel.

I've found I can run the 160's to 3300 but that's leaning on it awfully hard. Lot of powder depending I normally run them tween 3150-3200 on the top end. 7828 is the powder I use with 150's-160's.

My fire form load I've used for all 3 tubes is IMR 4350 with a 139 Horn flat base, it runs @ 3250 and is wicked accurate!!

4 me, it's a fun round. I was fortunate to know Hagel and called him a friend and that's why I run it.

If you've never read "One Mans Wilderness" by Page you should it's one of the greats!

Dober

I ran a couple of long-throat 7RM's that I hunted and shot with till the barrels wore out.They were set up so that the 160 Partition was seated with its' base was even with the base of the neck.This longer than 30/06 length,but easily doable in a Rem 700 action,or M70 with some modifications.

While still not quite the equal of the Mashburn,this set up ran 160's at about 3125-3140 with 7828;140's did 3300 or a bit under.I never had a problem of any kind.If you do it this way rather than with the 175,and the free bore is cut properly,accuracy will not suffer with lighter bullets.One of these rifles weighed 7.5 pounds;it was a favorite and would make composite groups with the 160 Partition,140 Partition,and 140 BBC you could cover with dimes and nickels.Barrels have all been Krieger 9 twist.

That said, I suspect the Mashburn will get a guy "there" easily,along with the Dakota, which is about the same thing.Both have more capacity than either the Remington or the Weatherby. Agree with Doc that the Mashburn is what the Remington shoulda been.....I mean, they had Pages data for a 22" Mashburn several years before the Remington mag was inroduced.

While I honor Bob Hagel and also Warren Page I would rather not have to fire form belted brass if there was a 7mm factory round thats similar.

I do like the 7mm bore for long range hunting however I am selling my 7mm WSM M70 as its just clunky.

Since I have other 'magnums' I am going to look at the Kimber 84L when it comes out. Since the advent of the laser rangefinders perhaps I don't need an extreme overbore magnum?

Its the rifle more than the cartridge to me.

Sorry about being slow, I am off line after noon CST. Wolfe Publishing has a BIG book of Handloader reprint articles available. It covers a LOT of cartridges. Go to their web site or call them and find it. Bob Hagel has an very thorough article re. Mashburn history/loading in it. Retumbo and RL-25 powders weren't available when Hagel did his article and I believe they are really execelent in this application. I use RL-25. As a reference, I use a current Hornady manual and 7 Roy data for loading inspiration.

As Bob says the Mashburn & Dakohata are about equal. Serious horse power is a right sized package

I suspect not many 'smiths have Mashburn reamers on hand anymore. I called JGS and they gave me a list of people that had bought that reamer and I rented it from a fellow in Oregon. You might call Dave Kiff at Pacific Tool or maybe Fred Zieglen for reamer rental/sources.

The easiest way to make brass is to use a RCBS form die set and start with .300 Win. Mag. I prefer Federal but anyones will do. The original parent case was .300 H&H.

Hmm.....I just happen to have a reamer sitting about 3 feet away from me at the puter...

Nothing like owning your own reamer.

Dober

Oh cripes......... That is information I did not need................. I got a Rimrock stock for a Classic action....and a Krieger #2 9 twist in the safe......oohh, man!

Bob, the brass is easy to make and if you travel and have lost your ammo, you can use 7 Rem.. DO IT!

True story. I was out at the local range one day and there were some 20 somethings out there shooting also. I asked what the gun was and the fellow said that he had inherited it from his Gpaw. It was a 7 mm Mag. He commented that the fired brass looked a little funny. I examined the said brass. He was shooting 7 Rem in a 50's 60's custom Mashburn. Groups weren't bad and I didn't have the heart to explain to the kid. He was happy and wouldn't have understood what I was talking about anyway.

Doc, that's a riot! I never woulda thunk it!

.............175 Partition at 3050....mmmmmm....sounds like an "anything" load to me......

Doc/Dober: Do you need a H&H length action for the Mashburn?

Just say the word and it's coming your way Bob.

Dober

Yes. I have mine on a Rem 700 but any H&H length action would do. Trying to put the 7 Rem in a 30-06 length action for conversion and ammo sales is what big green tried to do and that is how they go into trouble. The option to get Mashburn performance out of an 06 action would be to shorten the body/neck down the .375 Ruger to get the same useable case capacity and have a long neck.

There is no need for an STW/RUM capacity. You get WAY over the hump on the diminishing returns curve.

hmmmmm.

What's involved with using an M70 in 7RM (i.e. standard mag)?

I understand that the M 70 used a full length action and blocked the mag. box back to '06 length. If that is so, then remove the block or aquire a new mag box. You are looking at a COL of 3.565" +/- to get full performance.

If you long load a 7 Rem. you will get within about 50 fps. with a Rem but with less bullet flexibility.

To rechamber a 7 Rm you will need to turn off 1 thread and then run in the reamer. That's all the chamber takes. Magazine length is the other issue.

Consult an expert gunsmith on M 70's for best advice.

Thanks!

Does anybody make dies as a standard production item or is this a special order deal?

RCBS lists the set. Look on their chart and e-mail them as to availability.

I found some dies online. Forming dies for $165...A big 7 sounds fun and for a few reasons the RemMag is not as attractive. I wonder if dies for a 7mm-300 WinMag would be cheaper.

I am wondering, if the neck on the 300 Win is sometimes criticized for being too short, wouldn't it be even shorter if necked down?

One-caliber is often quoted as being the rule of thumb for necks and the .300 WM doesn't quite meet this. With that said I have owned several and never had trouble with bullets moving in the case with the bullet weights I use.

I supect a 7mm-300 would be fine in regards to neck legnth.

It is fine as is it is on the 300 winnie

Dober

I had a reamer made for the 7mm-300 Win and the neck was a little on the short side. It was very easy to load for. I have pushed the shoulder back on virgin 300 Win cases with no need for a form die. I believe the Mashburn had a 30 degree shoulder. If I was creating a "cat" from scratch I would keep the 25 degree shoulder of the Win and have a neck about .300". The capacity would be a little more than the Mashburn. Remember that Page built his last few rifles in 7 Rem Mag. The difference is not too much. It will move the 160's at 3050-3075 fps quite predicably. Pretty darn close and you can actually get over-the-counter ammo at Walmart. Sorry. I know it is common.

My recollection is that Page's Old Betsy was on a std length FN which had a 3.375" box. Hagel used an FN with the 3.58" box. Does anybody know?

RinB,

I have never owned a 7 RM (although hunted with a borrowed one once or twice), but all the bad press about its internal ballistics and the recent published velocities, which seem a little weak, have given me a bad impression of the cartridge and made me want something else (i.e. 7 Mashburn, 7 Weath, 7x61, etc.). I like the Mashburn and 7-300 because if on a hunt and I REALLY needed ammo. I would use 7 RM in them, which would be hard on the throat of either, but could get you out of a pinch. I don't think this would work with the others.

With that said, the 7 RM could be an excellent cartridge for all I know.

If someone can get Dave Petzal to chime in here, he knows where the rifle is and might even contact the owner and get a real measurement. Then all would know.

The neck on the Mashburn is .350" long. There is a cartridge drawing on Steve's pages for all to see. The design length is 3.48" if I remember correctly, so Page wouldn't have used a 3.375 box.

If you are looking at a 7mm/.300 Weatherby just do the STW. For all practical purposes it is the same thing. No up charge on the dies. The extra capacity doesn't get you much. You can shoot 7 Rem in the Mashburn chamber if you get really jammed up out beyond nowhere; you can't do that with any of the others.

Rin-I have both an article by Page and one by Hagel I can send to you if you wish. Just pm me your email. I think that Bob sent you the one by Page the other day?

One of my Mashburns is on a 700 and the other is a pretty gun on an Obendorf and this one will just plain knock your sox off!

Dober

Hagel wrote:

", after a good deal of correspondence with my friend Warren Page, who had just then started to use the 7mm Mashburn Super Magnum, I had Art Mashburn chamber a Douglas barrel for it and fit it to an FN series 300 magnum-length action."

One of my uncles had a 7mm Mashburn and a 10.75x68
both built on Enfield actions. I have never handled
these guns, but have photos of him with them, usually
with a deer. They "disappeared" after he passed away,
and nobody in the family knows what happened to them.

It was Warren Page's scribings about the 7mm Mashburn in the early 1950's that had me get a 7mm Ackley Mag built right after graduating from college in 1957. No one else had any influence for me making that decision, except for Warren Page.
I would have gone with a 7mm Mashburn, except that I had PO Ackley build the rifle; so, I chose his 7mm Mag.

b: To convert a M70 Classic in 300 win mag or 7RM to a H&H length box will require a H&H length magazine box and follower,replace or modify the bolt stop and ejector.If you don't the old ejector will hang over the magazine well,and you can't load the magazine.I used to order these parts from Winchester because I converted a couple of 300 Win Mags to H&H length.I do not know where to get parts for the Classic today.

In a pinch I have drilled out the spot welds on a win mag box, removed the spacer and tig welded the box together. The bolt stop and ejector can be carefully ground to fit with a Dremel.

I remember going in Mashburn's gun shop in OKC with my Dad when I was a little kid.....coolest place on the planet to a twelve year old gun fanatic. Mr. Mashburn was always very kind and patient with a little kid who read the Rifleman, G&A, Outdoor Life and Sports Afield cover to cover. That's where Daddy bought the old M70 fwt I still hunt with. and where I bought my first serious smallbore target rifle...a brand new Remington 521T....wish I still had it.

Very cool Steve, thanks for sharing.

Steve: That is neat....I have never seen a Mahburn rifle.From the looks of pictures of Page's rifle,they were well made.

BWALKER: Yes, you can modify the box and other parts to go H&H length.Not a bad idea even if you keep the rifle as a 7RM.

Bump for a killer round...

Dober

aka:

7em-em Mash-em Into A Stupor

bob - considering the mods. My only question is what I gain over my current 7RM and 26" tube. Anything less than 100 ft/sec seems a waste of time..................

Based on what I have seen, if you long load your 7 mm Rem, the difference is about 100-150 fps. The actual effective case capacity differance is about 3-5 grains. The long neck on the Mashburn gives you loading flexability with bullets re. stand-off from the lands (freebore) that the Rem doesn't have.

Max (63-65 K psi.)with a 175 in a Rem is about 2975-3040 fps. in a 24" barrel depending upon powder, etc. I the same barrel length a Mashburn gives about 3075-3130. YMMV.

b: I have never owned a Mashburn so cannot say;but see docbill's post above comparing the two cartridges.Keep in mind the Mashburn predated the Rem mag by quite a few years,and was likely one of the reasons for the Remington mags' existence,along with Les Bowman's work necking down the 338 Win Mag when it came out.he got non-headstamped 338 cases from Winchester;Fred Huntington put the first rifle together for Bowman.

I have(had) no way of testing pressures other than the typical methods many of us use,but my old favorite(long gone, shot out) lightweight,long throat 7RM put together by Butch Searcy did 3125 consistently with the 160 Partition;close to 3300 with the 140 Partition and 140 Bitterroot.My Dakota gives 3375 with the same bullets.It appears the Mashburn(and the Dakota) will beat these 7RM figures as note by docbill.

I will note I never had a pressure "problem" of ant kind at these velocities.Keep in mind a "throated" 7RM really becomes a 7mm Weatherby in essence;capacities are pretty much the same,and the Weatherby gets its higher velocity from being loaded to higher pressures and the Weatherby freebore.

BTW,the 140 gr,jumping that long throat,shot fabulously in my old rifle,contrary to what someitmes happens.

I suspect a guy could use these 4 cartridges with optimum loads for each(Mashburn,7RM, 7 Weatherby,and 7 Dakota) for a lifetime of hunting and never tell the difference.Page proved that these ballistics with a 175 gr bullet(yes, maybe old school is a very tough combo to beat for soft skinned game of many types,worldwide,coming almost to the performance of a 300 mag in a light rifle,without beating you into next week.

If anyone wants to run simulations with ballastic software, look at a 3100 fps 175 spitzer ( sd .313), Sierra just for fun, compared to a 200 gr. (sd .301) .30 cal. of the same make at 3000 fps. The 7 mm beats it on drop and equals it on energy at 400 yds. +. And no one ever even suggested that a 175 7 mm won't penetrate to the far side of the Moon.

Next compare the weight and recoil of the .300 Weatherby that will have to drive that 200 gr. at 3000+ fps. and think about which you would rather haul all over the toughest elk or goat mountain you can think of!

That was the trade off Warren Page thought of in 1950 whatever when he started talking about the Mashburn and such. The answer was good then and great now. The real issue is that unless you are a handloader and knowledgeable, the 7 mm Rem is grossly under loaded by the various factories and as such is just another 30-06. The Weatherby and Dakota are loaded to potential.

Gentelmen, choose your weapons and HUNT! Merry Turkey to all.

....Indeed....

I'm thinking a Mashburn on a Rem700 with a a really retro bird's eye maple stock in the "California" style would suit my fancy. Strangely those Weatherby stocks have grown on me over the years and they just seem fitting for a cartridge of this era.

I, brother, and freinds have loaded the 7 STW in custom barrels with minimum spec match chambers for deer hunting, to Weatherby pressures, you guys had ought to think about how the picture would change.

Keith,were you running 26" barrels with the STW?

25 1/2, 26, and 27's.

Thanks!

Keith;

For a 26" barrel what sort of velocities are you running with a 160 gr. or 175 gr. bullet?

I worked up a load with H1000 with the 162g SST when I first got the 27" barrel chambered, 3350 was the accuracy node; never shot the 175's.

I have a minimum SAAMI Match chamber, neck dia .002 over loaded dia, .2845 throat, zero freebore, 1 1/2* leade angle.

Winchester brass is the only brass that is tough.

Normally I shoot the 140g Nosler Combined Technology bullet at 3650 out of the 25 1/2" barrel using IMR 7828 with 215's, bullet seated to just barely touch the lands.

My brother's pac Nor three groove 27" barrel is so fast, I won't even quote the velocities using the 140g C/T bullet. Deer never take a step when hit with these speeds, in otherwords, all we have ever had were bang flops in 50+ deer killed.

Keith-if you don't mind how much 7828 are you pushing that 140 with?

Thx

Dober

Mark, there is a huge difference in loads between a 140g Barnes Tripple shock, the 140g Nosler Ballistic tip, and the 140g Nosler/Win Combined Tech bullet.

The C/T bullet does not build pressures anywhere near as fast as other 140's and I have been able to push it faster with out pressure issues.

Large sloppy factory chambers change the ballistics on this cartridge tremendously vs a Min spec chamber with +.0005 over bullet dia throat and minimal freebore.

For your rifle, you will just have to work up a load, stopping when you see pressure issues...you are a very experienced reloader.

I use Win brass since I can no longer get PMC 300 Weatherby brass to make these cases out of.

I also had excellent accuracy and velocity fireforming Rem 300 Weatherby brass with the 140's, but had to throw the brass away after fireforming due to enlarged primer pockets. If I knew how much bigger the Win Mag primer was, I would have kept the Rem brass for another couple of firings.

No problemo, for the most part I only run 7828 in my Mashburn and dats why I was curious.

Thx
Dober

Very cool writings on the old Mashburn. I have a few of Bob Hagels books out here. I have read them from cover to cover a few times over the last 15-16 years.

I have a 7WSM and 7 Rem Mag. As much as I would love to have another 7mm, the 7WSM and 7 Rem Mag will do mid 2900's with the 175 PT's and about 3100 with 160 AB's. I know the Mashburn really has a big benefit with the longer neck, but with the Model 70 7WSM, I can actually load the bullets for it out to around 3.00" so it gives me a little room to run. I haven't messed with the 7 Rem Mag in a long time, but I have a ton of 175 PT's, so I think when I get back home, I am going to bolt on the new B&C Medalist and see what it does.

Thanks for the reading, it was great.

Beretz: With guidance from Dober and Docbill on here,plus reading about everything Hagel and Page said about the cartridge,I built a 7 Mashburn Super about 2 years ago now.

I have been very happy with it,and have found the case easy to work with and a slight tick up from the smaller 7's when it comes to the heavy 7mm bullets many seem to like today.

There is no practical reason to have a Mashburn today, and put up with the inconvenience of the wildcat,especially since the gains over common factory stuff like the Remington,Weatherby,or WSM are only in the 100-150 fps range.

OTOH, if you want something a bit different that really works with heavy bullets,have an interest in cartridge history and development,like wildcats, and are bored to tears with "common" 7 mags,the Mashburn is a fun project that delivers the goods.And after you have one, those "other" 7 mags may well cease to have a reason for hanging around....they won't be needed.

After all, this is, or should be about fun and games anyway.

I'm gonna have to have a Mashburn, just cause Bob had one!

I'm going to use 160 Partitions in my Mashburn this year in honor of Bob.

I had one built last year, mainly due to Bob's never ending praise of the cartridge. Not my first wildcat but one of the easiest I've had to work with. As I told him in our frequent conversations, while I'm satisfied overall with the rifle, I suspect mine has a somewhat slow barrel. I've used Hornady, Norma, Remington and WW brass and none will allow me to get 3200fps with 160gr bullets and have any sort of case life. 3200 or more and primer pockets cease to hold primers after 3 shots at most, and my chamber has quite a lot longer throat than his. Given my experience with just my own rifle, I'm not so sure there is anything to gain over a 7mm Wby.

Way over book max load, bug hole accuracy on top end pressures.

I have a reamer that I bought when Bob helped me build my Mashburn and can supply a dummy round seated to Bobs specs.
If anyone is interested, you pay shipping both ways and if your smith screws up it needs to be replaced. I also reserve the right to refuse.
I do miss hearing Bobs opinions.

Amen to that Les. I cannot wait to get the new MSM out and shooting. Bob had a huge part in my current one (who am I kidding, I just copied his! )

Also, that is very cool of you to lend the reamer out. That is the spirit with keeping the old Mashburn alive and kicking.

"Sho, got that right."

John, what powders were you using with the 160s. A buddy of mine who shot side by side with me had a KS 7 Rem Mag that was rechambered and couldn't do much more than about 3150 without drama in his with anything. He tried Retumbo, H1000, H4831.. His gun, rechambered with another reamer just wouldn't do it. 24" barrel, same as mine. We never really "figured" it out. Bob, myself and another fella ran almost the exact same loads of H1000 (75.5) in Winchester and Hornady cases and got right at 3200 day in and day out. I couldn't wear out my Hornady cases.

Mine was a rechambered mid 90's Model 70 7mm Rem and it was set up to make a 160 AB touch the rifling at 3.605".. Same reamer I used for the new one I just put together.

And I will never say the Wby isn't GREAT, cause it really is, but it gets it speed with the freebore, the MSM doesn't have it. I am also not saying freebore is bad at all, I just prefer not to have it if possible.

I have been using RL-25 in my Mashburn for years. 76 gr gets me 3275 with good brass (Federal match .300 Win) life and Hornady 162 Interlocks. I think that this a little too high pressure so am backing down to 74-75 on my next load session. I would try RL-26 if I was going to work up a new powder and will when I use up the 3 lbs. I have on hand.

I once considered a Mashburn. But, my 7 Wby meets all of my needs. I honestly dont see how it could be improved or superseded.

Without a doubt, great cartridge.

Scotty,
I've used about every possible combination with the 160s. Retumbo, H1000, 7977, 7828, R22, R25, R26. My rifle is throated long, 160 ABs touch the lands at 3.670" so bullets get plenty of jump. Accuracy is very good overall with this throat length, especially with TTSXs. Bob and I had many conversations about this and we both came to the conclusion that I just have a slower barrel. 3150fps is about it's limit before case life goes down the drain. I don't think that another 50-75fps means much anyway.

For sure. I don't sweat it too much either. Just surprises me how some do it easily and others struggle to get there.