I had an M29 44mag. that always gave trouble ejecting the cases (very hard extraction) with magnum loads. It was better with mild loads, but not magnums. I fought with that revolver for like six years before I decided maybe I should try to polish the chambers. I got a big no on that from the S&W forums, they said I might damage it. They said call S&W and see what they say. So I gave S&W a call, and they said don't do anything, we'll look at it. They sent a prepaid UPS shipping sticker for me to send the gun. I got the revolver back in one week with a new cylinder and no charge whatsoever.
That was some excellent service that I'll never forget.