What type of ammunition should I use in my Ruger .40 Auto pistol?
The Ruger P91 and P944 pistols are chambered for the .40 S&W cartridge and are compatible with all ammunition loaded to U.S. Industry Standards, including high-velocity and hollow-point loads, loaded in brass, aluminum, or steel cartridge cases. .40 S&W ammunition manufactured in accordance with NATO, U.S., SAAMI, or CIP standards is within the design limits and known to function in these pistols.