The biggest physical difference between rifle and pistol primers is the length. A rifle primer is longer, and if seated in the shorter pistol primer pocket, the primer will be beyond the back of the cartridge. In a revolver, it will keep the cylinder from rotating. In an auto, your headspace will be off, and may get a slam-fire.
If you're going to put high pressure pistol rounds together, just use the small pistol magnum primers. You'll get a thicker cup, which stands up better to the pressure, as well as a hotter/longer burn. I've seen no ill effects from using magnum primers in .38 special loads, and in a Handi, you shouldn't see any problem at all.
I know that the .500 S&W brass from Starline is made to accomodate a large rifle primer correctly. Not sure about the .357 Max, though, so some research might be in order.