I posted this the other day but that thread is gone. I thought I would put it up because it may help someone save some grief. This is a quick easy way to verify that your freebore is close to what it should be. I can usually get within .005" of the true length doing this. Which is close enough for freebore length. This one is a .140". So if you come up with .130-.150 and the print says .140, it probably is. This will tell you if something is far enough off to cause an issue.