Gas Ring Worn Out?

[.38SPL enthusiast]

Does any one here know why a revolver would have an uneven gas ring?
I'm talking about the ring on the cylinder around the ejector rod. I have an old M&P from `47 that has this problem. It allows one side of the cylinder face to rub the breech when I shut it, but once its shut everything is lined up and tight. I don't see how it could be wear, the guns appears to have very few rounds through it.
Old manufacturing defect? Any ideas would be great

 

[James K]

I am not sure what you mean by "it allows one side of the cylinder face to rub the breech." I assume you mean one area of the cylinder face is rubbing on the end of the barrel, and my reply is based on that assumption. Let me know if I am wrong.

The gas ring should have nothing to do with the cylinder rubbing the barrel. Cylinder end-movement ("end shake") on an S&W revolver is controlled by the end of the crane arbor contacting the inside of the cylinder; the gas ring is only to keep powder fouling out of the ejector opening.

The cause of the problem could be the crane being out of alignment, the cylinder itself being machined incorrectly, etc. I think it might be a good idea to take the revolver to a competent pistol smith or contact S&W for their advice.

Jim

 

[T. O'Heir]

I'd bet the crane is slightly bent.

 

[.38SPL enthusiast]

Yeah I think I might have to have someone look at it. It is the cylinder face rubbing the end of the barrel. I originally thought it was an uneven cylinder face, but then I noticed that one side of the gas ring collar is uneven, and when the cylinder is shut it seems to flex just a little in the direction of the uneveness. The crane looks perfectly tight and a range rod will pass through effortlessly on every chamber. I hope to get it in better repair one of these days.