I have to disagree that they are bomb proof.

Someone at the club bought a ROA. The cylinder, when it is at full cock would not lock up tight, it could be moved about .020" in either direction of the barrel centreline.
It was either badly worn internally, or had been bodged up by someone. I did not look at the slots on the cylinder itself but I don;t think they would have been worn. It had no accuracy at all probably because the ball was being shaved if the cylinder moved to one side when it was fired.

All that glitters is not gold, as they say.
Anything you buy second hand needs to be checked thoroughly. It is too late once you have parted with your hard earned dosh.