Yes this is confusing. I know the 6.5x50 is a jap round that goes with the type 38 but the 6.5x51R that has been talked about also going to the type 38 early model. Is this true or a misnomer? Or are they the same when discussed about the type 38. My book of rifles, first printed 1948 states a 6.5 type 38 with no mention of a rimmed cartridge, instead it says semi- rimmed, necked cartridge.?No.
6.5x51R, indicates a rimmed round, case length 51mm.
6.5x50, is a rimless round. Just to confuse things, some recent 6.5x50 brass has been marked 6.5x51(without the R).
I appreciate the feedback on this cartridge guys. I looked back into my sierra reload manual and it says the case length is 1.974 inches ( 50 mm ) and my Lee reload manual states 2.008 inches (51 mm ). so it appears to be the same round all along. The diagrams show semi-rimmed for both .The 6.5 x 50 Japanese round is a semi-rimmed cartridge.