Sometimes you'll see it on .45 Colt... but that is not to a SAAMI standard. And unlike the other +P's, "heavy .45 Colt", the kind of modern ammunition built specifically for Ruger and Freedom Arms revolvers are way beyond original spec, which was is a cartridge that has it's roots in black powder. But the "market" and fanbase for "heavy .45 Colt" is probably large enough that if I had to guess... it could be or might be the next actual SAAMI standardization of a +P rating.
.38 Super is often labeled +P also, but there is no SAAMI standard for .38 Super+P and it's often been said that some makers label .38 Super as +P simply to help denote the fact that it is not the much older .38 Auto. And in fact... some .38 Super (and marked +P at that!) is simply loaded to lower than allowed peak pressures. I personally believe that Magtech's .38 Super+P product does this.
Buffalo Bore does it to some of their ammo...
They shouldn't.
.38 Super is often labeled +P also, but there is no SAAMI standard for .38 Super+P and it's often been said that some makers label .38 Super as +P simply to help denote the fact that it is not the much older .38 Auto. And in fact... some .38 Super (and marked +P at that!) is simply loaded to lower than allowed peak pressures. I personally believe that Magtech's .38 Super+P product does this.
Buffalo Bore does it to some of their ammo...
They shouldn't.