Overpressure ammunition

Overpressure ammunition, commonly designated as +P or +P+ (pronounced Plus-P or Plus-P-Plus), is small arms ammunition that has been loaded to produce a higher internal pressure when fired than is standard for ammunition of its caliber (see internal ballistics), but less than the pressures generated by a proof round. This is done typically to produce ammunition with higher muzzle velocity, muzzle energy, and stopping power, such as ammunition used for security, defensive, or hunting purposes. Because of this, +P ammunition is typically found in handgun calibers which might be used for paramilitary forces, armed security, and defensive purposes.