I purchased a used 351C a few months ago and have had nothing but
problems with it. Primary problem is the cases swelling in the chambers
and not being able to eject them. First cylinder of seven rounds and it
takes a good rap with a block of wood to force the cases out. 2nd problem, is trigger pull. I know that I'm probably stuck with the pull as is.

I have used JB compound to polish each chamber and that did not work.
Does anyone make a steel replacement cylinder for the 351c? Has
anyone had a similar problem and found a solution? I've already had a
bad experience with a 317 snub nose and S&W service center. I was
able to pass it on to someone else. Don't want to go back to the service
center. Hope someone has some ideas, suggestions on this problem.
TIA

Might try different brands of ammo? past that I would send it into S&W sadly.

You might be able to find a gunsmith, but I do know that if it came to me I would do some basic trouble shooing, might polish chambers if they look rough, but ultimately I would say that S&W needs to correct it. it could be something under over size in chambers from a bad reamer ext. a tight throat causing pressure to build. ammunition would be my first test though.