By Top Of Bore, I meant diameter B in the referenced chart. Again, the whole thing that changed my thinking that it was a 24 vs a tight 20 was the 15MM proof mark, which is much closer to a 24 than a 20. I am using a RCBS dial caliper to measure, which obviously isn't the most accurate as I initially cam up with a measurement that was .001 under that of the snap cap, which isn't possible!

Last edited by Joe U; 01/24/17 09:48 AM.
Joe U