MRW,
that depends on what you mean by "work"...!!
i bought a "NO-GO" gage, read the instructions..., then said to hell with it..!!
in the instructions it says that some bolts will close & lock on a "NO-GO" gage......, soooooooo, tried it in a few of my used AR-15s, locks up nice & tight........,
tried it in two NIBs, locked up one, not the other..., get a "FIELD" gage, if you get a lock up one of those..., you got problems !!!!!