Saint Elmer held forth on the strength of the J-frame .38s, and I concur. I've owned several, and would never be troubled by shooting an unlimited amount of .38+P ammo through the steel frames.

My last Model 36 no-dash, I didn't shoot much that wasn't +P through it. Hundreds and hundreds of rounds of it - and stuff well beyond SAAMI's +P standard as well. Gun didn't bat an eye. A neighbor who needed a carry gun talked me out of that one, but it was still going strong and still tight as a drum.

I have a customized 36-1 that might be my favorite pistol ever (don't ask me why - I have no idea, really) that essentially does not get shot with anything below what's presently rated as +P rounds. Steel-framed gun, offset bolt notches, short forcing cone protrusion into the cylinder window - the only thing that could get hurt by a 20,000 PSI round would seem to be the hand of a less-than-rugged shooter.

Don't rely on what we say, though. Contact S&W with the serial number if you want the official story. You should do whatever makes you comfortable after you research the issue, though - perhaps all the Model 36s that I've shot/owned have been exceptionally strong ones.