The correct shell holder is RCBS # 9 , Norma cases are on the small side . PPU has bad quality control so they can vary . The PPU .268 bullets are closer to .267 and they do not have the problems caused by Hornady's bad .268 bullet design . So any normal powder for that type round will be fine with the PPU bullets . Carcano bore sizes did change over the years . The early rifles had grooves about .270 + , then about .268 , with late made M-41's having bores as small as .266 ish . The military bullet is right at .266 dia and was made to be a bore rider like the rest at that time . The main thing to look for is the total bore area - land and groove and the combination of both . That and gain twist or not will be a major factor on what bullet to use . That is what Emery did not understand and why he kept breaking rifles . I wrote an article a long time ago when the Hornady .268 first came out [after test firing about 400 in many different rifles , bore sizes and loads ] that told what was wrong with the bullet design and why it causes problems in some rifles .