300 Magnums

[Edd]

All it accomplishes is making the freebore shorter. That could be something you want and it could be something you don't want. You need to make that choice based on the bullets you want to use.

 

[Edd]

You could make the brass from 338 Lapua brass. But if that is your plan, you might want to consider a 300 Lapua.

300 Norma brass shouldn't be hard to find.