Quote Originally Posted by ArtinNC View Post
Not true !! close the bolt on a empty chamber holding the trigger back so it is NOT cocked and you will have a little end play . A uncocked firing pin has a little end play. I dought that if I removed my barrel and remover a couple thousands from the barrel it would make any difference in the way that it shoots .
To prove me wrong you mark the bolthead, you close the bolt while pulling the trigger and thrusting the bolt forward. I concede. You got me.

I somehow missed that closing the bolt on an empty chamber while pulling the trigger demonstrated your problem. Close the bolt like you would normally and there is no end play.

I don't find the of closing the bolt while holding down the trigger to be used in troubleshooting any known issue that I am aware of. If there is "end play" between the bolt head and the breech in the uncocked position, there is no reason to machine your barrel.