from the old forum:
A customer encountered some diameter problems with his 600 gr. mold for a S&W 500.
The bullets were dropping out 0.504" - 0.505", regardless of alloy. It turned out that the handles were binding on the blocks so that the mold could not close completely. The customer was able to fix that himself (note: my current procedure is to test handle fit with both RCBS and Lee handles on each and every mold, but handles have tolerances, too .....).
After sizing in a 0.501" die, the bullets were about 0.5025". It turned out that the 0.501" die was not 0.501". A pure lead bullet pushed completely through the die measured 0.5019" - 0.5023". The customer is still trying to locate or make an appropriate die (he lives in Argentina).
0.500" jacketed bullets would chamber easily in his gun but the 0.5025" bullets would not chamber at all. He thinks there is not sufficient clearance around the case neck (the cast bullet has a bore riding nose so the nose should not be hitting the throat). He believes his throats are 0.501". That doesn't leave a lot of wiggle room for experimenting with bullet diameters.
I just thought the various dimensional problems were interesting. We learn something new every day.