Well I took out John's M barrel today and ran it with various types of ammo. Greek 1938 vin runs without a flaw I bought a few thousand a few years back. Polish 30's vin again no problems just a couple of duds. EK headstamp 40's ran ok. yugo 1950 ran alright, any other year forget it. yugo in the ammostore barrel no problems. I guess I buy romain just for John's barrel.