This is why having in-depth mechanical knowledge of revolvers is so important. Especially when most revolvers are "used".

You never know how someone treated it prior to you, and it doesn't take that many overpressure rounds to ruin parts. Factor in that a gun could still look brand new externally even after 100s and 100s of rounds. So you just can't expect everything is like new.

You can't rely on sellers to make sure you get a sound revolver either. I remember a certain refinished gun with a cracked forcing cone trying to be pawned off on someone from a well respected internet dealer. Just goes to show how much the so called "reputable" dealers know.