This is a new to me 637-2. Where the front of the cylinder contacts the frame it is sort of chewed up, and where the cylinder meets the back of the frame there is are marks from the rim of the cartridge. I'm not concerned about how they devalue the revolver since it was purchased for a song, but instead what exactly did the previous owner do to cause the marks.

This is a new to me 637-2. Where the front of the cylinder contacts the frame it is sort of chewed up, and where the cylinder meets the back of the frame there is are marks from the rim of the cartridge. I'm not concerned about how they devalue the revolver since it was purchased for a song, but instead what exactly did the previous owner do to cause the marks.

Simply firing the gun makes those marks. On discharge, the gun recoils backward, and the cylinder, attached to the crane through it's inertia, slams forward into the frame. It tends to bounce a bit during cycling, and the ratchet hub impacts the rear of the frame.

That's why excessive cylinder fore-and-aft movement (endplay) increases as a gun is fired more, until headspace increases and the barrel-to-cylinder gap decreases to the point of unserviceability. The hotter the loads, the lighter the gun, the more pronounced the movement is. Uncorrected excessive endplay can be very damaging to a revolver.

That wear comes from closing the cylinder. On my replacement 642-1 from S&W I have been trying to get the cylinder to not stick when opening and after many repetitions it no longer sticks but has much deeper marks then yours. I have never fired mine yet.