I've shot a couple of Smith 19s out of time training, practicing, and shooting some exhibition, but a newly fitted cylinder hand, and later on a newly fitted oversize cylinder stop, some more shooting, and they were ready for trade.
Mostly I was shooting very light 38 special with cast bullets, but they got more than their share of hot 125 grain jacketed hollow points also.
On many occasions I have fired a thousand rounds in one day, with never a hitch, and these were K frames. As far as what the factory says, they would prefer that you never fired them, and just bought another one. They will never tell you to shoot hot loads in their pistols. At least they didn't used to.