Kellywk:
Make the MSM. I use the COW method to final form brass; it doesn't waste bullets and expensive powder. Any pistol or shotgun powder will work. Bob has Quality brass and 40 should last quite a few hunts. For anything in the US, reformed .300 Win. is cheap and in endless supply.
As a disclaimer, I have 2 MSM's and one is a rechambered 7 Rem.
YMMV and my $.02 worth.
