As I posted before, the throats opened enough to accept the next sized plug gauge. Whether that is more or less than 0.001" is hard to say, since the gauges are graduated in steps of 0.001".
But, it was darned clear that the cylinder throats opened some with firing less than 100 rounds of Federal "Champion" .45 ACP ammo. That is the Walmart cheap stuff with thick-plated 230 grain TMJ bullets (that turned out to be as much as 0.004" out-of-round) and cases with small pistol primer pockets.
Another 100 rounds did not get them to 0.052, so I am assuming that I was polishing-off some surface roughness, and maybe peening the surfaces a bit. I usually do this with revolvers to make sure that the barrel threads are fully forced-out into the frame threads before I start looking for any barrel constriction to remove.