Home Forums Reloading Big Game Rifles 7mm Mashburn Super Mag?

I have read about Warren Paige and his 7mm Mashburn Super Mag rifles. Can anyone tell me any history or details on this round. What parent case was used, if any. I think it is a little faster than a 7mm Rem Mag, but does anyone have any ballistic information on what can be achieved safely? How can brass be formed now. I think I read before it can be formed fairly simply from 300 Win Mag brass? Thanks for any information anyone can give!

This is what I found.
https://www.ballisticstudies.com/Knowledgebase/7mm+Practical.html

The round was originally formed from cutdown 300 H&H brass. The easier answer now is to use high quality 300 Win brass. Push back the shoulder and reduce the neck, fire form with Cream of Wheat.
It has about 8 grains more case capacity than a 7 mm Rem with a longer neck and 30 deg shoulder.
There are a number of articles on the Fire from 2011-12 about performance. It is easy to get 3050 with a 175 using H1000 (72-73 gr. in my gun) 3200 with a 160 is safely obtainable. Al of this in a 7.5-8 lb package and very good accuracy if your smith does a good job. One thing that my smith has done is cut a 1.5 deg throat.
With the long neck you can load with the base of the bullet at the neck base and use all of the case capacity.
It is NOT a 7mm Practical.
The round is not a full length H&H like the STW nor a shortened round like the 7mm Rem. It is just right.
Bob Hagel also wrote an article for Rifle magazine which is available in the old Big book of articles that they published.

DocBill nailed all of it. There’s a handful of us that’s been running it for a few years and as stated, with a 24” barrel most of us are in the 3050-3100 range with 175’s using anything from H1000-V570

3200 or better with the same powders. Plenty of room in the case if you have a 3.6” magazine and a rifle set up for it.

I use RWS or ADG 300 Win, ran through form and trim dies and then a Redding Bushing die to get the neck tension I want.