As others have mentioned, there is no SAAMI standard for +P+. But back in the day, the Illinois State Police used 115 gr +P+ in their S&W autos; the ammo was purchased on a state contract and the contract itself had pressure limits. I don't have a copy any more, but the limits weren't much higher than +P. The contract velocity was 1,300 fps from a S&W Model 59.
I bought the ammo for my small department and test fired each lot. The Winchester +P+ always made the 1,300 fps floor and usually did about 1,330 from my Hi Power. The Federal 9BPLE only made the velocity spec about half of the time and typically clocked around 1,280 fps for me. Of course, velocity and pressure are not completely correlated, and current production might be different.
An ISP instructor wanted to see how long his 59 would last with the +P+, last I heard he had fired something like 50k rds with only normal parts replacements.
I did have a 940 (J-frame 9mm) and it would lock up when the +P+ would jam the case heads against the recoil shield.
