+P vs. +P+ Ammunition

Today, it seems like too many manufacturers go out of their way to make their products look better than that of their competitors by slapping some exaggerated information on the packaging. And you might be wondering if ammunition is the same way. Well, we’re going to cover a little bit of that in this blog as it pertains to +P and +P+ ammunition. What do the markings mean, and is there really a difference between the two and a standard load? I’ll also cover some debate areas on this particular ammunition topic, so keep reading to learn more.

What is +P Ammunition?

First off, what does +P mean? It means overpressure. If you’re running +P, you have ammunition that’s above the standard pressure given by SAAMI and NATO specs. Some resources say +P stands for extra pressure. At the end of the day, they both mean the same thing, so we aren’t too hung up on it.


In the simplest terms, +P ammunition is ammo with a little extra gunpowder. That gives it more power, created by extra pressure. This happens because the additional powder is packed in, that packing and extra ignitable material makes a load with higher internal pressures.

If the manufacturer were instead going to make a longer cartridge, it wouldn’t be the same; there wouldn’t be as much of a forceful explosion. The lack of space to expand is what helps to create extra pressure.

Why +P Ammo?

If you’re sitting there and don’t know much about +P ammunition or why you should get it, just because there’s extra pressure, this section is for you. However, remember where I said there’s some debate, yup, you guessed it, the need for +P is also a debated topic among shooters. So, I’ll give you both sides, and you can determine if +P is for you or not.

at GunMag Warehouse
Prices accurate at time of writing

+P Ammunition Gives you More Speed, More Energy, More Stopping Power

The benefit of good +P ammunition is that it should have more power. Notice I used “good” and “should.” Which is where the debate comes from. 

Assuming you have quality +P ammunition, there should be a significant difference in power, which translates to stopping power. So, if you’re looking for self-defense ammo, +P can be a good option.

+P Doesn’t Give Significantly Consistent Speed, Energy, or Stopping Power

And now we have the second argument. The difference is standard ammo, and +P ammo isn’t significant enough to warrant the extra money you’ll need to dish out for the extra pressure. If you have cheap ammo, chances are, this will be the outcome for you. However, quality ammo should have a difference. 

Now, something to keep in mind here when testing ammo. A lot of environmental factors go into the numbers you get from muzzle velocity and muzzle energy (kinetic energy). So, you won’t always get the same numbers the ammo companies did in their perfect environments. Of course, there’s also the possibility that the velocity and energy printed on the box exaggerate the results. 


In some cases (with some types of ammunition), instead of spending extra money on 9mm +P, it’s better to get yourself a higher caliber, such as standard .40 or .45, because the significance isn’t there.

How Does +P Ammunition Work?

Assuming you have the good stuff, +P can be a good option. The advantage of good +P is that it has more stopping power, and it has more stopping power because it’s a faster bullet.  The faster a bullet is, the further it can potentially penetrate.

To understand that, we need to go back to the basics of firing your pistol.

When you pull the trigger, it puts into motion the events needed to set off the primer, which happens when the firing pin hits the primer. When the primer is set off, it creates an explosive charge. This ignites the charge. When it’s ignited, a lot of pressure builds up. And since the pressure is looking for a way to escape, it does in the form of a bullet being sent through the barrel, out of the muzzle, and hopefully onto your target.

Liberty Ultra Lights 9mm Ammo

+P is an extra charge, meaning more pressure. And with more pressure, you get more speed. Also, an advantage of quality +P is that the extra speed means it keeps its trajectory for a longer distance. That means your bullet won’t drop as quickly, and you’re more likely to hit whatever you were aiming at, not below the target—you also have to be a good shot. Please don’t leave this article thinking ammo fixes the human error. It does play a part, but if you suck at shooting, well, you suck. Fix that before spending a bunch of money on +P or +P+ ammo, in hopes that it will somehow compensate for your poor shot placement as a result of your mediocre skills.

SAAMI’s Pressure Ceiling for +P Ammo

Since I brought it up earlier, I thought I’d cover SAAMI really quickly before moving onto +P+. SAMMI stands for Sporting Arms and Ammunition Manufacturers’ Institute, and they standardize the shooting industry. In that, they have something for +P ammunition known as a pressure ceiling, which for 9mm is at 38,500 PSI—A standard load is 35,000 PSI.

What is +P+ Ammunition?

If +P means overpressure, then what does +P+ mean? 

Yes, +P+ ammunition is rare, but that doesn’t mean it’s nonexistent. What it does mean is that it exceeds the +P standard. It also isn’t given a pressure ceiling under SAAMI. So, anything over 38,500 PSI is considered +P+ ammo.

And just like +P ammo, it’s got more charge and should have more energy, more stopping power, and it’s also going to cost you more money.

at Primary Arms
Prices accurate at time of writing

Just like +P, considering this has even more pressure, it’s not compatible with all firearms. Check your user/owner manual or call the manufacture to determine if you can fire +P+ ammo through your firearm.

Is Overpressure Ammo Bad for my Gun?

The answer is, it depends. I know you probably don’t like that answer. But, it depends on your gun. Some firearms just aren’t built to take the higher pressure rounds. If you try to fire higher internal pressure rounds through a gun that can’t withstand that extra pressure, then you could end up with damage to your firearm, and you could even injure yourself.

at Primary Arms
Prices accurate at time of writing

If you aren’t sure about your particular gun, the best thing you can do is talk with your firearm manufacturer and ask if it can shoot +P ammo. Or check the user manual, assuming you didn’t throw it away—the information is likely to be in there, depending on how old the firearm is.

A good rule of thumb, and maybe you’ve seen it but don’t know what it means, but you probably shouldn’t fire +P or +P+ ammo through a LC (lightweight, compact) pistols.

Did we miss anything? Do you have further recommendations? Please, comment below. We love hearing from our readers!

Table of Contents

  • What is +P Ammunition?
  • Why +P Ammo?
  • +P Ammunition Gives you More Speed, More Energy, More Stopping Power
  • +P Doesn’t Give Significantly Consistent Speed, Energy, or Stopping Power
  • How Does +P Ammunition Work?
  • SAAMI’s Pressure Ceiling for +P Ammo
  • What is +P+ Ammunition?
  • Is Overpressure Ammo Bad for my Gun?

Leave a Reply

Your email address will not be published. Required fields are marked *