If you are trying to get the most “oomph” out of your modern defensive handgun or PCC - Pistol Caliber Carbine, then +P ammo should be at the top of your list.

What is “+P” ammunition and why do some rounds have it but others don’t?

Many 9mm shooters will have seen +P ammo on self defense ammo, since it is fairly common. If you shoot 38 Special or even 45 ACP you will likely have seen the +P on a box or two of ammo. Have you ever seen it on a box of 40 S&W? Probably not (though it does exist and comes with it quite a few warnings.)

Plus P (or just “+P”) ammo is ammunition that is loaded to meet Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) standards for being over-pressured. SAAMI sets the standard for commercial ammunition manufacturers to follow when producing ammunition. One of those standards is the average pressure per square inch.

As an example, SAAMI specifies that the proper pressure for 9mm is 35,000 PSI. SAAMI also specifies that 9mm +P ammunition PSI levels should be no more than 38,500 - which is 10% greater than standard. While SAAMI has these standards for many different rounds, they do not have them for every round. 40 S&W for example doesn’t have a published +P range - so anything that says it is 40 S&W +P is not approved by SAAMI.

Depending on who you talk to, that isn’t necessarily a bad thing. People can reload their own rounds to pressures well in excess of the stats that SAAMI publishes. Is it wise? Well that is up to each shooter to decide.

What are the benefits of +P ammunition?

There are a few benefits to +P ammunition. For instance, because of the extra pressure, projectiles travel at a greater velocity resulting in a flatter trajectory, which improves accuracy. The increase in velocity also equates to an increase in energy.

Due to the increase in velocity, +P ammunition is most commonly found in self-defense rounds. When your round is traveling at a higher velocity, it will hit the target with more force, which helps a self-defense round do its job of stopping the bad guy better. Even a small increase in velocity can result in a huge percentage gain when it comes to energy transferred. Plus P ammunition also excels in snub-nosed revolvers and other small barrel concealed carry size pistols. This is because the increase in pressure can compensate for the shorter barrel lengths.

Of course, there are tradeoffs.

What are the drawbacks of +P ammunition?

Everything we’ve mentioned so far is great: higher velocity, more “knock down” power… but what are you giving up to get those?

All of that extra velocity has to go somewhere. The increased pressure in +P ammunition results in more recoil and flash. It’s not uncommon for people shooting +P ammunition to refer to it as being more “snappy”. This is only exacerbated when being shot out of a short barreled handgun. More snap, or recoil, increases the time it takes shooters to get back on target for follow-up shots. So that is one tradeoff.

Additionally, +P ammunition can speed up wear and tear on your firearm. The added pressure increases the force placed on the moving parts and that wears them out faster. Especially the small parts that are more prone to breaking. It also increases the friction in your barrel, which can reduce your overall barrel longevity. However, most of us do the majority of our training with target rounds, and use our self-defense ammunition at a much less frequent rate, so there’s that to consider.

Additionally, while most firearms are rated for +P ammunition, not all are. It is important to verify that your firearm can handle the extra pressure from the +P ammunition. Consider +P a no-go if you have an older gun that you suspect might not be able to handle the higher pressure.

Like all aspects of life there are tradeoffs. If you want more velocity and more energy on target you’ll need to ante up and pay for it with more felt recoil, a louder boom, and more flash - not to mention greater wear and tear on your gun.

The bottom line is that +P is a good option for many situations - self defense ammo in a modern handgun shot by someone that doesn’t mind the extra recoil. If you are older and/or shoot an older gun and can do without the extra velocity then +P isn’t for you.

[Incidentally this is why when you sign up for our service and choose Self Defense ammo in 9mm, 45 ACP, 38 Special and 380 ACP, we also give you the option to choose NO +P AMMO… because not everyone wants the extra “oomph”.]