Home Forums Hunting & Shooting Long Range Hunting The Big 7's......Which One?

Handloader article was wrong and was confusing 2 Mashburn cartridges. There were both a full length STW version and the SHORT version that used shortened .300 H&H brass. The SHORTENED version is what Page, Hagel, Duber, and Bob use.

Dang docbill, that is an interesting clarification. of course, you just doubled the life of this thread with that post!!



two Mashburns to discuss now. i'd be curious to know who shoots the LONG 7mm MASHBURN these days...

I don't know for sure but I'd think that the Long version wouldn't have anymore case cap. In fact I wouldn't be suprised if it wasn't less...?

But, I've been wrong b4 and will again

The authority on this trivia is the old PO Ackley book. Art Mashburn had a whole series of wildcat cartridges from about .25 up to at least .375.

Find PO"s book and use as a reference just DO NOT repeat DO NOT use the load data.

Does anyone know who's reamer the RCBS dies are spec'd for? Redding told me that their custom dies are based on the JGS print, which is a little different than the PTG print. I am interested in doing a little experimenting. I have been running 180's in the 7RM at 3050 in 26-27" barrels and wanted to do a comparison with the larger case as well.

So does this mean that Mr. Dobrenski will have to clarify his sig line, with a foot note as to WHICH 7mm Mashburn he is doing the saving?

The JGS print is for the short/Super Mashburn using .300 Win mag brass. Call JGS and ask them to fax you a drawing and do the same with PTG and compare to be sure. The Mashburn I run is off of the JGS print and I own one of their reamers. That is also the one RCBS dies match.

Docbill,

I have both prints, and the PTG version is slightly different. I will order the JGS reamer so the dies match up a little better.

Dogger, no, not needed....Docbill is right..Art Mashburn found the full length Mashburn case less efficient back then and the shorter case that we are all using to be the more "efficient" of the two.As a result he named our case the 7mm Mashburn Super

The full length case was much like the 7mm/300 Weatherby or STW of today.....of course they both work, and we have more powders today to help them.Both these cases are peas in a pod, both being full length 300H&H cases blown out and necked down.

But even today neither one really shades the 7mm Mashburn Super by very much. The "Super" is the cartridge that Hagel and Page used for their hunting for years,and the case Dober uses also.That it is formed from 300 Win Mag cases today should tell us the case is more intermediate in length, sitting between cases the length of the 7mm Rem Mag and Weatherby mag on the one hand, and the 7mm STW on the other.

If you call RCBS to order dies, this is the one you will wind up with far as I know..

Interesting... so... the easiest way to get into a 7mm Mashburn Super is to take a 7mm Rem Mag of your choice and have a smith ream the chamber? Order the dies from RCBS... obtain the 300winmag hulls, and bingo, you are in bidness?

My wife is going to shoot me...

The simple answer is ............YES !!!!!!

And use the Hornady loading manual 7 MM Roy load data. If it is safe in the Roy it should be safe in the Mashburn and remember to use a chronograph.

Gonna need at least a 26 inch tube to realize the gain, I am sure?

Hmmm... are you gentlemen running 24 or 26 inch barrels on your Mashburn Supers?

This may sound weird to those who love walnut, but my idea of the perfect 7mm Mashburn Super (for me) would be a stainless M700 settled into their black LSS stock... will I be disappointed with a 24 inch barrel?

I've had them in 23" and 25", thinking Bob and most normals run 24".

The Black LSS looks nice but I like the weight out front not rearward so I tend to avoid plywood handles. But, that's just my way.

Dober

Now try this on for size to be different. .280 Dubiel Mag (full length .300 H&H necked down) running .284s in place of the original .288. Feeds slicker than vasoline on a brass door knob!

I bought Remmies

Dogger: No, I doubt it. Mine and my pal's rifles were built from a pair of Krieger #2's, both 9 twist,on M70 Classic actions.Warren Page's rifle, Old Betsy,had a 22" barrel and he got 3050 with the old 175 Nosler partition with 73 of WW II 4831.

In my barrel I get the following velocities:
73-H1000-175 Nosler Partition for 3075 fps.
75-H1000-160 Nosler partition and Bitterroot for 3175 fps.75.5 puts either bullet over 3200 fps.

Matt's rifle takes a grain or so more powder for the same velocities.The cartridge gets these velocities rather easily. I am getting data from other folks indicating these velocities are "typical".

I do not push the envelope with this cartridge as there is no need for it....there is "room" in my loads and I could go higher, but the cartridge in a 24" barrel is basically a 175 at about 3050-3075; a 160 at 3175-3250 (max).

No doubt you would get more speed from a longer barrel, but I wanted a general purpose hunting rifle weighing 8# or under with a 24" barrel.....that is what I got.

Docbill is right about using 7mm Weatherby data but from our experiences watch out for the maximimum loads of Retumbo in the Nosler manual with 160's. In Matt's rifle 79.5 of Retumbo (Nosler max in the Weatherby)gave the 160 AB 3250.I dropped back to 78 gr in my rifle and got 3330(!)No blown primer but over the top. This is still a wildcat,so be cautious and work up.

That's right. I was just ready to write about the one Page used and the page turned and there was your post.

Yes you are in business, and yes, you will be hung.Join the club.

Lordy. I am slipping fast into the Mashburn Super Vortex...

I need to get my hands on an M700 7RM so I can convert it...

Thanks for the heads up on the rifle balance, I also like weight forward, but I sure do like that LSS stock!! Perhaps a heavier contoured 24 inch tube will restore the overall setup to weight-forward righteousness?