I've practiced shooting quite a few DA only rounds, as fast as I could pull the trigger. I would say I've put 100 or so rounds through like that, and maybe 100 or so slow fire, SA only.
Should I refrain from this type of practice?
Like you said, those could be burs getting flattened from the looks of it.
I checked the timing as best I know how, and it appears to be OK.
The cylinder does wobble a bit when not in full lock up, but is fairly tight when locked up. The chambers apear to be in line with the barrel when in full lock up. I'm probably just worrying about nothing, the gun still functions fine, no lead spitting or anything.