7mm mashburn super magnum

[BravoLee]

I own a 7mm Mashburn Super Magnum built by Mashburn Arms Company in the 60's. It was built for the late Joe DeSaye founder of J&G Rifle Ranch and has accounted for a lot of animals. He loaded it off the 300 H&H shortened, blown out, and necked down to 7mm with 160 gr Nosler Partitions at 3100 fps. I have loaded for it, shot many rounds through it, and I have found it is very tolerable of lighter weight bullets as well as heavier bullets and is an extremely accurate round. I'm currently shooting what Mr. Joe shot out of it because that old man knew exactly what he was doing.
RCBS made a set of custom dies for him that I am using, but I'm not sure if they still make any.

[sambubba]

Bob Hagel said it is much easier to use the .300 Win mag cases and run them thru a forming die. You end up with a longer neck than either the .300 Winnie or the 7mm Rem mag. I use this process and currently have three of the 7mm Mash S Mag rifles. It loves IMR 7828 with Rl22 a close second. I throated mine like Hagel suggested with a 160g Nosler seated to the neck base.

Craig

[RJ338]

As the previous posters have said you can form the Mashburn Super from 300Win brass. It moves the sholder back and changes the angle to approx 32 degrees, giving you a longer neck. Only reminder is to be sure and anneal the necks after forming.