ADG brass??

[ThrdKllr]

You may need to form 7mmRM first then 264.

 

[Ed AO]

I'm shooting some adg, mixed results so far. I'm going to run it a little more and see what happens. Never had a problem with Nosler brass, on the fifth firing. This is with my 28

 

[Buzzsaw]

my calibers out of stock everywhere but I have enough, Peterson and Alpha to last a LOOOONNNGGG Time

 

[arch408]

Yeah, the 264 Win Mag was out before the 7mm Rem Mag, so you could say the 7 mag is based off the 264 Win mag...
Not to put too fine a point on it but Lance is essentially correct, both cartridges are based off the same case dimensions, the difference being caliber.

OP, I think the 7 Mag offering from ADG may be a better choice, if that's what you want to do.

7mm RM brass is a lot better way to go. It would be a simple neck resize. If you used the .300 WM, you would have to push the shoulder back, trim and probably have to ream the necks.

 

[ADG Brass]

Our WM and 7RM brass are formed quite differently. Having no data on what your doing, I would say that the WM brass is going to too think in area that will become the new neck.