I decided to send my 629-3 back to S&W for a general overhaul. I bought the gun new in Feb. 91 and it has seen a lot of use since. The barrel-cylinder gap had increased to around .011 and I was getting lot of crud build up in yoke which caused the cylinder to be hard to turn in cold weather. The crud appeared to be cast bullet lube- it probably won't have been a big issue with jacketed bullets.
I sent the gun off by prepaid Fed-Ex on the 6th and received it back today- a pretty quick turn-around and a week or so faster than I've had with my Ruger Redhawk.
In the return packing slip S&W stated the Customer Complaint was " B & C Open". They Repaired "Cut forcing cone" and "Turn barrel". It appears that they removed the barrel, set it back a turn, re-faced the breech end, recut the forcing cone, replaced the yoke, and cleaned up the yoke to frame fit.
Now is the gun is pretty much back good as new mechanically wise and will probably outlast me before it needs service again. It is getting pretty scratched up and externally worn by now but I see that as a badge of expereince - my guns don't have to be pretty.
My "hats-off" to S&W! I'll call them tomorrow and thank them. Good service needs to be rewarded even more than poor service deserves complaints.