Home Forums Hunting & Shooting Custom Rifles & Wildcats What the heck is a 7mm Mashburn super magnum.

What can you fellow's tell me about this round.Is it close to my beloved STW or 7 Rem.Or is it larger than both.Heard a little about it but really know zero for this round.Is their other Mashburn magnums?
Thanks for any and all replies.

The super Mashburn is a 300 H&H necked down to accept .284 boolits. Mark D. here has one and loves it, perhaps he'll chime in and give you more dirt on it.

It is the forerunner of the 7mm Rem mag developed by Art Mashburn of Oklahoma. Warren Page and Bob Hagel used this cartridge extensively all over the world and loved it. It can be made from either 300 H&H or .300 Win mag cases. The latter is the easiest. It is a somewhat shortened .300 Win mag case that is necked down and reformed in a forming die with a much longer neck than the .300 Win mag case. It is ideal capacity for a 7mm magnum. Bob Hagel's loads produced velocities of 3300+ for the 160g Nosler partition and 3100 or a bit more with the 175g Nosler. He got his best velocities with the now discontinued Norma 205. IMR 7828 is the best choice now. I currently have three barrels in this chambering. It makes a very flat shooting and hard hitting cartridge capable of killing everything in NA, although if hunting the big bears Hagel would tell you use a .340 Weatherby (not that the Mashburn would not do the job). Mark Dobrenski, a campfire member, also has/had several barrels in this chambering.

Art Mashburn was a prolific wildcatter, the father of the .218 Mashburn Bee, 7mm, .30, .35 and .375s based on the shortened H&H case with a 30 degree shoulder, and a slew of others.

The 7mm Mashburn Super Magnum is the full length 300 H&H necked down and blown out, not the shortened version.

In other words, it is the 7mm STW fifty-plus years ago. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

Warren Page used it all over the world, and racked up an incredible list of big game animals with it.

Ted

So, everything being equal, the Super Mashburn is virtually identical to the 7mm Weatherby?

I'm so confused.

In my discussions with Mark D. I was led to believe that the Mashburn was simply a necked down H&H. Now I hear its a shortened and blown out or standard length and blown out.

Rolly .... The 7mm Roy IS a shortened blown out H&H case. If the mashburn is shortened then yes.

PM Mark Dobrenski on this board. I believe he shoots one. Steve

The reamer I have for the &mm Mashburn Super Magnum from JGS is for the 300 Win Mag length case. As Sambubba stated it is easiest to reform 300 Win brass, shoulder is moved back and given a 30 deg. with longer neck length just as Bob Hagel described. You can go to the Clymer rreamer site and check specs on chamber. I personally think it has about the optimal capacity for this bore, more than a 7MM Wby and less than a 7STW. Downside is it is a wildcat, or to some that would be an upside!

Yukoner, he had two versions, the shorter one I described which was the one Page, Hagel and the rest of the shooting world knew as the 7mm Mashburn Super Mag and the full length version that Ackley called 7mm Mashburn Mag(long). You would have thought that the first one would be called the short and the long one the Super, but that is not the way it worked out. Maybe the short was monickered the Super because it had optimum efficiency and was still very powerful and great in the game fields, who knows?

Surfed around a little bit and found THREE Mashburn magnums.

No descriptions for them though:

7mm Mashburn short mag.
7mm Mashburn long mag.
7mm Mashburn super mag.

Is it possible everyone is talking about a different cartridge and just think they're talking about the same???

George, the short mag is the Super Mag. I have three of them, all of Page's and Hagel's books, and the article written for Rifle Magazine by Hagel on the Super Mag.--#103 starting on page 26.

Sambubba,

I always thought that Art Mashburn had two versions, as well. But I can't find any reference on it.

The only thing I can find is in Rifle #103 in an article by Bob Hagel. He states that the case length is 2.635". The #4 Speer Manual for wildcat cartridges agrees with this. They also list 2.635".

John J. Donnelly in his book Handloader's Manual of Cartridges Conversions lists the case length as 2.625.

That's all the information I have in print.

It's nice to have a Shooting Library at one's fingertips. Even tho' you can't always find what you want. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Grasshopper

ok .... other than being a gnat's nipple away from a .275 H&H, what would a 300 H&H JUST necked down to accept .284 boolits be called .... no blowing out of the case, just necking down?

7mm-300 H&H??

Thanx!

Sounds good to me.

You might check with board member "TamTom" a.k.a. Tom Mason. Besides being extremely knowledgeable in general he used to work at Mashburn Arms............DJ

An interesting side note is that Page's Mashburn had only a 22in. barrel. I read an artical by him just a couple of weeks ago and his all around load was a 175gr. Nosler semi point at 3050fps.

P.O Ackley lists 3 different mashburn 7mm's the short
is similar to Ackley,S&H, 285 Luft etc. show 160 at max 3020
next is super mag. he says this is same case as the 270 and 6.5 mashburn
shows 160 at max. 3270 and then mashburn long is made by necking
300 H&H and leaving full lenght and says to use weatherby data, hope this helps. Cheers NC

Was that the rifle he called "Old Betsy"?

You got it. "Old Betsy".