Home Forums Hunting & Shooting Long Range Hunting 7mm Mashburn VS the 7mm Weatherby

Case capacities:
7 Rem 84
7 Roy 86
7 Mashburn 89

The reason that I use Weatherby load data is that the Roy has freebore and the Mashburn more case capacity. They to me are swaps. The Hornady load book has the Roy producing 3,100 fps. with a 175, thus that is my chrono. limit for the Mashburn.

You are showing a 6% increase in powder capacity for the Mashburn. We know from JB's ballistic rules that for a 10% in case capacity we will get a 2 1/2% increase in velocity at the same pressure level
So there is no real velocity gain at the same pressure

And if you read what I said and everyone else says about loading the Mashburn, you will see that none of us load it faster than the Roy and it will only get you about 100 fps. more than a Rem loaded up a with a long COL.

Basically everyone is going to the trouble of a wildcat for about 1 1/2% velocity gain at the same pressure.

I have read and understand the ballistics, but have a difficult time understand the allure

All the math and formula's may be true....I would never dispute that.

And maybe I might be guilty of not leaning on the peddle enough with the 7 Rem Mag to get it up close enough to what I get with the Mashburn...but then I have been hunting with,loading for,and shooting with the 7Rem Mag since the early 70's.

..but I will say that across the board I have found the slightly increased capacity of the Mashburn makes it easier to get the velocities from it,than what I see from a variety of 7mm Rem Mags,which tend to be sort of a crap shoot,at least at pressures that I "think" I can live with(as a backyard handloader, I have nothing to rely on other than the ordinary and traditional pressure indicators,coupled with a sense of survival and 40 years handloading experience

And what else I do know is that loads and data and delivered velocties for the 7 RM can be all over the map,rifle to rifle....using due caution,and watching traditional data for the Mashburn,easily gives me that 3050-3100 with a 175 gr bullet, and 3175 to 3250 with a 160. I have not run a 140 because I have no need for that;it took me 6 shots to bring a 7mm Dakota to 3375 with a 140 from a 24"Krieger barrel.It,and the Mashburn, are similar cartridges.The delivered velocities are so similar, I can't distinguish between them. No one would argue, that the Dakota is not a faster cartridge than the 7 Rem Mag.It logically follows that the Mashburn is, as well.

Near as I can tell with what I have to work with,a Mashburn is 100-150 fps faster than what I have seen with optimum loads form a 7 mm Rem Mag.Comparisons are pointless, but I guess ineveitable.

In a day and age when we can "justify" the excrutiatingly small differences to squeeze a 300 WSM between a 30/06 and a 300 Win mag, or a 280AI between a 280 and a 7mm Rem Mag,it is ironic that we can at the same time nitpick and say a Mashburn is not "worth it"....maybe to some, but to others it's exactly what they want..Others are entitled to their views,and their choice of cartridges that they "like".

That's my story and I'm stickin' to it.

There's only one thing to do then--don't get one.

Never even considered, the notion, Fret none

Hmmm, now that's interesting. According to JB's "Quarter rule", the Mash should only give about 40fps more than a 7RM that pushes a 160gr bullet at 3100fps. It seem to me, and I may be wrong here, that if we take two rifles that are throated equally, one chambered in 7Mash and the other in 7RM, the Mash should be getting about 3200fps (according to reports by trustworthy guys here), and the RM should be at 3150fps. Interestingly enough, 3150fps in the 7RM is about the top end of what published data used to show 20-30 years ago. I guess the logical explanation is that the 7RM is being loaded to a little bit lighter pressure than an equivalent Mash.

Perhaps the velocity consistency between MSM rifles is due to precision-built, custom reamers and custom dies being used with the MSM, while all sorts of sloppy factory chambers and throats are floating around in 7RM. I wonder if the same characteristics that guys are seeing in the MSM would also be found in 7RM rifles if both were built with quality reamers and barrels, and with equally generous throats.

Jordan,

That can indeed be part of the problem with the 7mm Remington Magnum, and was especially true during the first couple decades of the cartridge, when it became wildly popular and every rifle company on earth was cranking them out.

Back then, too, European manufacturers didn't quite adhere to the chambering standards for American cartridges. I know this from experiences with older European rifles chambered for some American rounds, even the .30-06!

I'm guessing one reason my Browning High-Power 7mm RM gets such nice velocities is something about the throat dimensions, and possibly even the bore itself--which is as good as any hand-lapped custom barrel I've ever stuck a bore-scope down. The rifle is certainly getting more zip from handloads than the manuals show, but without any sign at all of excessive pressure. I've seen the opposite in other 7mm RM rifles.

I've seen the same thing in my 7WSM. Published loads tend to give higher velocities than what the data reports. My Husky H-5000 7RM was the same way. No traditional pressure signs, but higher velocities than those reported when using book loads. Some of my loads for that rifle came from older, more liberal manuals, too.

Interesting.

No disagreement here. Traditional pressure signs on brass is unreliable as I know that you know, without pressure testing equipment. My 338 Lapua with 300 SMK's is average in regards to velocity and book loads, but with the 250 grain SMK my rifle gets 3200 FPS with book loads and no signs of excess pressure, but again those were not pressure tested.

I agree a properly throated and built 7Rm should be very close in velocity

It isn't uncommon to see 7mm barrels of different manufacture give different velocities with the same load.I have seen differences of slightly over 200 fps between different rifles....

The Mashburn seems to do with a 175 gr bullet and 24" barrel,what an optimally loaded 7 Rem Mag does with a 160 IME....3040 to 3090.

This makes sense, because it holds more powder.This is also in line with what Hagel and Page reported for the cartridge years ago...and mostly with WW II H4831...we have more,and better slow burners today.

It ain't just a club, it's a brotherhood! The SMashburns.

Whew, that was a close one, I was really getting worried for a while there.

My pal JWP is a 30 caliber sorta guy...

The Smash Brothers.....

Dober

Couple thoughts, first off years back (mid 80's) one night 3 of us ran ammo from the exact same box thru our 7 Rems. All 24" tubes, same clock etc.

M70=2850

Sako=2925

700=3045

175 Nozler semi's.


Part two of this is I agree with Bob in that most 7 Rm's that I've been around would go to 3K with the 160 to 3050. If pushed they'd go 3075 but I can't hardly recall one going 3100.

Oddly enough I've not seen much for speed diff tween with the 7 RM in regards to the 160 and 175. Interestingly I've found in the .270 that there isn't much diff tween the 140 and 150 either. Thought I'd toss that out just for giggles.

Dober

The 7mm SMASHBURN SUPER .............Mmmmm .....sorta catchy...

I've gotta haul some wood but b4 I go I'll say this about the speed debates.

The speed I've gotten out of 3 barrels with the Smashburn has been without pushing them Hard. I could lean on them and get more speed for sure. As well I could work with different powders and get more speed.

One of the things I've noticed over the years is the varrying degree of how hard some are willing to lean on a round. Back in the day I was a 3 term President of Red Liners. Bout a decade ago I choose to get a round I liked, get a decent speed out of it with super accuracy and go hunt. The advent of decent LRF's helped it a lot. As did dotz, turrets etc.

As well, there's certain rounds that I like to work with as they give me the kind of speed I want (note I said I want and I'm not up for debating why I want this or that, it's totally my decision). I like to use a case that will get me there with ease, not via leaning on it.

There's fellas on the Fire that go places with rounds that I just won't, and that's fine. They're driving, I'm not behind the wheel they are. If someone took that attitude with the Mashburn I'm fairly certain speeds would be quite a bit flashier.

Now generally it's my opinion that over the course I've not been able to go to the places they could. Could of been some fast barrel slow barrel syndrom going on. Or fast clock days and slow clock days and we know that that happens. But, in all likely hood I sense that they like the round and they're gonna get the round where they want it one way or another. Once again, it's fine with me. Though I care about them and would hate to have them have serious issues with the rounds and how they're pushing them in the end their grown men and have their choices to make.

From time to time I'll hear people say, "I can put .3 or so more powder to it and I'll get to X number of Zero's"...grin. Running a 223 or small case I understand the .3 thing, but by and large I've found with large cases it's a waste of time and is only something to be pulled out when one wants to get to the Zero's.

The Mashburn gets me what I want (with a proven track record of good primer pocket life), and for the reasons I want. Myself or Bob have never tried to convince anyone that they need one. Now do we like the round yes, and does it fit what we want out a round. Yes it does, it's a great fit for me and my other "Smashbrother".

But for others it just aint gonna work and that's fine with me. It's all fun and that's about it. I do find it sort of amusing how many wanna piss and moan or try to douse the fire and that's fine as well. Would I prefer them to say it's just not for me and move on, yeah that would be nice. I just don't have time to try to justify what I use and or why. Unless of course my Wife or Mom wants me to I've reached and age where I'm just not going there...grin

Lastly, could I do most all I want to do with a host of others rounds aside from the Mash. Yes I could, but then I'd be compromising a bit from want I want in a round. Not much, but I would be compromising a bit. For me, a lightish .270 and a Mashburn set up to go long (700 via dotz or 1K via turret) is a very good set up for me.

Gotta run and haul some wood for Mom...grin

Chao Po Ahora

Dober

Cool, where can I get one of these?

Also, I've never seen the specs on a Mashburn or a Super Mashburn.

Are they based on a .300 Win mag case and a .300 H&H case?