As noted by earlier respondents:
End play or yoke shake.
Gas cutting of the top strap
gas cutting of the forcing cone
Look at the screwheads. Are they buggered up? If so then it's been worked on by an amateur.
A lot of guns get dropped, and a lot of revolvers get closed by uncultured philistines who insist on flipping the cylinder home with a flick of their wrist. This can spring the crane and make the gun problematic.