[Unclenick]

Actually, unless it's a brand new gun, you want the FIELD rather than the NO-GO. The former determines end of service life, while the latter is used in cutting the chamber. There is no fixed SAAMI standard for NO-GO. It's just the gage maker's best guess as to how tight a newly cut chamber should be.

Commercial gages pretty much always have an ejector space groove cut in to them these days. The extractor should not be an issue as it just goes in the gage extractor groove. These gages are strong, and you can stretch a chamber camming one in with the locking lugs, so you want the bolt free and not under recoil spring force.