IIRC there was a cylinder recall way back on 29 or 629's.
They do break trigger pivots. I broke my 4" 629-1 blasting 300 grainers max'd out.
Cost me $5 to ship it back, they fixed it pretty fast too.
I have also seen the nickle 442's crack frames (alloy). Three of them (locally- different owners).
Smith gave them new stainless versions as replacements.
With the 629 Classic they changed some things. Slight, but one of the changes was stepped areas then having radius- the trigger pivot being one of them.
The 500 is on the X frame and that's just a different beast.
Now there is a kinda famous story about a M29 and a SBH that blew up (reported in gun mag way back), but time and the internet have made it take all sorts of forms. I actually know the guy that blew 'em up, friend of my dad.
Wrong powder the culprit.