S&M recommends ammo that meets SAAMI specs (
SAAMI | Sporting Arms and Ammunition Manufacturers' Institute). In short, SAAMI avg energy recommendations for 9mm 124 grain =350psi. +P is 385psi and Winchester Nato 9mm is 358psi. The website lists lots of other data including velocity. Not much difference beteen SAAMI and NATO. NATO is within the range, high, but in there. Certainly its not +P. I like it and shoot it in my Shield regularly.