I second (or third, or ???) that the cylinder throat diameter is the only thing you are ever going to be able to come to a conclusion about, so you should avoid buying bullets that are going to get swaged coming out of the cylinder.

The first time I went poking around trying to measure the bore of a revolver I was gobsmacked... The damn thing, that shoots like a laser, had an insane constriction where the barrel was screwed into the frame. After discovering the SAME THING on two more infallible shooters, I quit.

As long as the bullet passes into the barrel intact, it will (and of course I'm only talking about lead bullets that are getting a good solid push to a decent velocity) be the right size at the right time.

Speaking of Matt Dardas, his bullets are the only ones that have got me out to 150 yards from a 1911 with accuracy and punch. I'd swear that the low melting point lube is half the trick, it's a little like the slime that's on 22lr match bullets.