Compression Ring End Gap

Aww man...I have some cheap *** snap bore gimmicks I drop in there, at a few different levels and side to side locations then measure them with a caliper. Is it as accurate as a dial bore gauge? Heck no, but it's pretty close, for what I do. So you were going to shove the ring around and take end gap readings n different places? That outta tell you something..taper, at the least