Funny you bring up the M29. I bought a 4" blued one in 82 or 83. The first weekend I had it a buddy and I burned through 650 rounds of reloads (mostly) and factory loads I had. We quit when the little slotted nut that the rear sight elevation screw threads into stripped out.
On the way back to the apartment on Sunday I stopped by the big outdoor/hunting/fishing shop I'd bought it from and showed it to them. They told me to take it to the back and give it to the guy at the counter and they'd have their gunsmith look at it the next day. I told them I didn't need a gunsmith for that, just sell me the nut and I'd replace it. The guy looked at me like I was stupid and said, "We can't stock parts for every gun we sell." I told him that all the S&W adjustable rear sight revolvers probably used the same little nut and he turned around and walked off. I never moved out of WV three years later without ever buying another gun, box of bullets or can of powder from them.
I got to work Monday afternoon and told the Chief about my brand new broken M29. He said he bet he could find a nut for it. He got on the phone and called Brownie's Gun Shop a few miles down the river. He got off the phone, told the other guy to watch things for a bit and we jumped in his car and drove about 10 minutes down the road towards Charleston and pulled into a little town. He drove up to a house, we got out, knocked on the door and a guy came to the door. We followed him around the house to his garage/gun shop, I showed him the stripped out nut. He grabbed a book, looked it up, went over to a wall of those little parts divider drawer organizers, pulled one open, pulled out a small bag and removed one S&W rear sight elevation nut and handed it to me. It cost about $0.85. I felt so bad for putting him to all that trouble (he was eating dinner with his family) I bought a set of "Mustang" finger groove grips for the M29. I put them on and just couldn't use them (fingers on top of the humps instead of down in the grooves). The M29 never stripped out a sight elevation nut again.
I'll bet Brownie is long gone these days. Not many shops like his back then, let alone now.