The issue isn't really about whether the gun will blow up or anything, but heavy loads will definately accelerate the wear on a gun that wasn't designed to handle them. My thought would be to find a good 158-grain non Plus-P load like the old lead hollow point, and practice with it, it's not prohibitively expensive. Some folks will carry +P's in the gun, but only practice with standard loads. The theory there is that if you need to use the gun in a SSS (Serious Social Situation) You'll be a lot less concerned about the gun than you are about your own keister. I'm rather partial to the Speer 135-grain Gold Dot load mentioned above, I doubt anything else will work as well out of a snubby!
PJ