What is +P?

by
posted on February 21, 2017
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
winchester-9mm-op.jpg

SAAMI, the Sporting Arms and Ammunition Manufacturers' Institute, sets standards for chamber and ammunition dimensions and ammunition pressures in the United States.

Voluntary adherence by makers assures the shooter that all ammo will fit and safely fire in all firearms for which it is intended. SAAMI lists a few handgun cartridges at higher-than-normal standard pressure, called “+P.” Note that “higher pressure” does not mean “high pressure.” These +P loads in 9mm, .38 Special and .45 ACP are only nine to 10 percent above standard SAAMI pressure—nowhere near approaching magnum loads that might be twice that of the parent design. Note that these cartridges are all 100 or more years old.

Improvements in metallurgy and handgun design make +P loads viable in modern firearms, but shooting +P in older guns could be disastrous, and a steady diet of +P in some modern guns may wear them out prematurely. If your handgun is not marked, “+P,” don’t shoot +P ammo in it until you contact the firearm manufacturer and learn whether it is safe to do so. SAAMI, incidentally, does not have a standard for +P+ ammunition, which various sources list as approximately 18 to 30 percent over SAAMI standard pressure.

Learn more about SAAMI here: www.saami.org.

Latest

Usashooting 2025Sept 1
Usashooting 2025Sept 1

U.S. Shotgun Team Reigns Supreme in 2025 International Season

Team USA’s shotgun athletes have captured 34 international medals in 2025, showcasing excellence from Olympic legends to junior stars

Review: Springfield Armory SAINT Victor 5.56 Rifle

Springfield Armory’s SAINT Victor 5.56 is loaded with enhancements that make it a strong contender as an all-purpose, AR-style rifle

Remington’s .22 Short Rimfire Ammo is Back

Remington brings back the .22 Short rimfire with updated loads for plinking, pest control and beginner training.

SK Customs Unveils ‘Kingdom of Atzlán’ Colt 1911 Series Honoring Aztec Heritage

SK Customs’ new .38 Super Colt 1911 handgun series blends Aztec mythology with handcrafted firearm artistry

Drew Cup Selection: U.S. Juniors Set Sights on Prestigious International Smallbore Showdown

The 2025 Drew Cup brings elite international smallbore competition to U.S. soil, where junior shooters compete for national pride via a postal qualifier

Competitors’ Corner: September 2025

Highlights from the September 2025 issue of Shooting Sports USA, the NRA’s competitive shooting journal

Interests



Get the best of Shooting Sports USA delivered to your inbox.