I have heard that the 416 Rigby brass would not handle high pressure loads. Which is why the 338 Lapua was developed. Is the Jamison brass able to handle higher pressure than the originals
Dr B

to use a quaint phrase, "horsepuckey" my good man. 416 Rigby by Norma is a bit soft...as is all of their DGR cartridge lineup from my experience. My 510KX (510 Wells minus the belt) fired one MAST 416 cylindrical six times with a 2300fps 650gr load. No case stretch or pressure ring, etc. Another "story" IMHO, based on the fact that the brits load a case big enough to get 410gr @2400fps @ low pressure. People say the same thing about 30-30 cases, made to a lower standard. Imagine the lawsuit if such a thing were true? I am hammering mine pretty hard.

Rich