I have a rifle that someone apparently re-chambered to 8mm Rem Mag. It belongs to a friend of mine actually and he brought it to me to look over. I have no information on who did the chambering job. I ordered a set of Go and No Go gauges to check its headspace to make sure that it was safe to fire. When I received the gauges, I could get the bolt to close on either gauge. It does not even begin to close on the Go gauge. A factory 8mm Rem Mag round chambers just fine. What do you think? Thanks for any help.