thats my point...the .348 resized brass is actually a little too small in rim diameter..which works as long as you let the Breech block push the cartridge in. Otherwise you stand the chance of the extractor not being engaged. The bertram brass was not good .....too thick for the shell holders I had and the brass itself was thin. But I'm not at the point where I want to run a .50-70 reamer into my 12.7 x44 chamber,,,,