I wonder if there's lot to lot variation or if it's possible that there's enough temperature induced change to account for the range in sizes? My mircmeters must be calibrated throughout their range at least once a year by a metrology lab, so the mikes ought to be OK. I have posted previously sizes of 0.2673" and 0.2675" in different threads, including this one:

More 6.5 Carcano fun coming!

So, maybe lot variations? Probably not significant. It's not uncommon to find military bullets that vary more in diameter around the circumference of one bullet!

---------- Post added at 02:44 AM ---------- Previous post was at 02:38 AM ----------


An old photo of a sample measurement of a milsurp bullet.