On my 8mm mauser project gun with the used 8MM excellent bore Czech barrel after installation not only did the gun pass the field headspace gauge(the bolt won't close on it) a while back, it also passed the No-Go Gauge too today. It chambers a round so I'm sure it passes the Go gauge too.(the bolt fully closes) I will still fire it very carefully for the first round(tie it down and pull the trigger with a string method) just to besafe but I'm sure it will pass.(with hot turk ammo) When checking barrels it may fail the No-Go gauge (close on it) but using the field gauge next if it doesn't close on it the barrel may still have some life left in it. If it closes on the field gauge don't shoot the gun its not safe to shoot. BigBill
