The plus P distinction of the ammunition means that there is added pressure to that cartridge. The added pressure of the cartridge gives the bullet a higher velocity and more energy than the normal identicle cartridge. Most modern firearms can handle plus P rated ammunition, however there are some that cannot. Please check your firearm manual or with the manufacturer of your firearm before attempting to shoot plus P rounds.
Hornady Critical Duty 9mm Luger Plus P Handgun Ammunition Specifications:
Caliber: 9mm Luger
Bullet Type: FlexLock
Bullet Weight: 135 grains
Muzzle Velocity: 1110 feet per second
Muzzle Energy: 369 foot pounds
20 Rounds per box