So I moved my 30P-1 TBAC over to my GAP 300 PRC. It had a fat bastard brake on it. When I thread the 30P-1 all the way down there is a slight gap but it is down all the way.
Could be a carbon ring inside the can if it's been shot on another rifle with different-length threads, give me a call to discuss. 307-287-2052
If it gets tight at all while threading it on, don't continue doing it, it can cause galling