+P and +P+ Cartridges: The Good, Bad and Ugly

So what are +P and +P+ rounds? In a nutshell they are rounds loaded to produce higher pressures which in turn produce better ballistic performance, i.e. they allow you to shoot a heavier bullet without losing velocity. +P produces between 9 and 12% more pressure and +P+ produces more. They are exactly the same dimensions as a standard round so will chamber and fire in a standard gun.

(Note) +P and +P+ rounds should only be fired in guns rated for them by the manufacturer.

In 1926 Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) was founded with the objective of:

• Creating and publishing industry standards for safety, interchangeability, reliability and quality
• Coordinating technical data
• Promoting safe and responsible firearms use

They set the industry standards for ammunition which manufacturers use when designing ammo and guns. SAMMI classes +P as a separate caliber and lists only four +P calibers.

• 9mm Luger +P
• 38 Special +P
• 38 Super Automatic +P
• 45 Automatic +P

(Note) SAAMI does not list any standards for +P+

The Good

You will get better ballistic performance from your firearm. The bullet will penetrate deeper and expand more.

The Bad

• Felt recoil will increase as you have upped the pressure of the round without corresponding increase in gun weight. This makes rapid accurate follow up shots more challenging.
• Your gun will wear out faster even though it is rated for those cartridges.

The Ugly

• Some manufacturers state their guns can handle +P rounds (e.g. Khar). Some ammo manufacturer’s offer +P rounds in calibers other than those SAAMI lists. So if SAAMI sets no standard for these calibers, how can gun manufacturer state their gun can handle them???
• There is no standard for +P+ so who knows what you are subjecting your gun to.
• Being the same size as regular cartridges you can fire them from your regular gun by mistake.
• They will void manufacturer’s warranty if your gun is not specifically rated for them.

The Most important requirement of Defensive ammunition is that it is 100% reliable in your gun when your life depends on it.

The most important requirement of your Defensive Gun Ammo combination is that you can quickly and accurately place multiple shots on target.

In my opinion The Bad and the Ugly outweigh The Good. With one exception, I do not use or recommend +P or +P+ rounds for defensive shooting. If you want better ballistic performance get a bigger caliber gun. It will be designed for the higher pressures and to handle the recoil.

The one exception is using 38 Special +P in a 357 Magnum. The Magnum is designed for higher pressure than the +P so it will not overstress the gun and will actually reduce the felt recoil making gun more manageable.