Hey, thanks guys! Also, can anyone recommend any reloading manuals for 37x223R?
I'm thinking start with 4500 grains IMR 3031 and work up from there?
Small or large rifle primer do you think?
(All kidding aside, the brass in question came from my great-grandfather's collection of inert WWII materiel; he was a machinist at the Brooklyn Navy Yards and I guess they used to get a lot of scrap and non-conforming materials. This one's 37x223R brass, dated 1943, probably originally meant for an M3/5/6).