Reinz, I think (but could be wrong) that +P doesn't make that much difference in a barrel UNDER 3 inches.
Looking at Federal HST 9mm 124g and their +P, it's 50 ft/sec difference coming out of a 4" barrel. Not much, as you say. Approximately 32 lb-ft more energy too in the +P.
I'd say coming out of the R9, the difference would be much less due to the probability not all the powder would have burned.
When I first read Reinz's statement, I thought the same as you, but looking at it for a moment, he is correct, there is no significant difference in velocity coming out of a three inch or larger barrel, so even less coming out of a sub three inch barreled pistol.
Mute point, I no longer use +p ammo, I did when it was all the rage many years ago, okay, I do use it in a revolver, I use 38+p in my .357 on occasion.
I just don't see the need to use +p for the slight benefit if any. Good controlled shots is the key, as stated above.
