What could be causing this?

[Auto426]

Nope, OP's post #15

Just because he treats his guns well, does not mean that everyone that has ever picked that gun up has. A previous owner or a friend that borrowed it may not have been as well edjucated on gun handling, and may have practiced their movie style wrist flicks or may have dropped the gun on the cylinder, causing some alignment issues.

 

[stevieboy]

Ok, so I took it to a local Smith who fixed the problem for a grand total of $36. The problem, according to him, was excessive end shake. Excessive play was causing the cylinder to occasionally jam up against the forcing cone. His cure, a couple of shims. I haven't fired it yet, will do so tomorrow. However, the differences between before and after are remarkable. There is now almost no back-forth movement of the cylinder. The gun now cycles smoothly without any rubbing of the cylinder face against the forcing cone. The forcing cone-cylinder gap is now consistent throughout a six round cycle. And, best of all, the trigger feels markedly lighter, now that I'm not forcing the cylinder to rotate against resistance. I'll post a range report tomorrow.

 

[stevieboy]

Problem fixed!! Took it to the range yesterday. There was no binding whatsoever and the gun is a tack driver again.