This was posted by jumping frog in a thread labled SR9 + P capability which is just down from this post.
SAAMI 9mm Luger 35,000 psi
9 mm NATO 36,550 psi
SAAMI 9mm Luger +P 38,500 psi
9mm Luger +P+ ???? no defined standard.
The proofing test pressure used in both the 9 mm Luger C.I.P. proof test and 9mm NATO proof test is 45,687 psi.
According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) guidelines the 9x19mm Parabellum case can handle up to 235 MPa (34,083 psi) piezo pressure. In C.I.P. regulated countries every pistol cartridge combo has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.
Since it has to pass a 30% safety margin proof test, it is safe to say that the Ruger SR9 is going to handle "normal" ammo that is reasonably close to specifications.
I would say its probably a safe bet to get the ballistics info on any type of +p+ ammo just to make sure it dose not exceed the capabilites of the pistol, seeing's how it looks like there are no defined standards for it.
I read in another forum that competitors routinely use 147-gr 9mm for the occasions when they have to shoot steel "bobber" targets. Apparently the slight extra weight aids in reliable knock-down of the plates. I hope to re-enter the competition arena this month, and I'll be using my SR9 with 147-grain loads.