By Sam Hoober, Alien Gear Holsters
New gun owners and carriers have to get some carry ammo for their new carry pistol or home defense handgun, and might notice that the only stuff left on store shelves says that it’s “+P.” Or they might have been told by someone that +P ammo is what they should have to defend themselves.
If that’s you, we’ll go over what +P ammo is and whether or not it’s what you should get, or if you should avoid it. The short answer is if it’s what you can get, it’s probably fine.
As far as what you might have heard about it well, sometimes it’s true and sometimes it isn’t. We’ll go over that too.
So, what is +P ammo?
The +P designation means “overpressure,” meaning the ammunition has a little bit more powder than the standard loading and therefore the projectile is (in theory!) propelled to a faster velocity than the standard recipe for that caliber.
For instance, standard 115-grain 9mm loads typically propel the projectile to about 1150 feet per second, give or take about 30 fps because it varies with every shot fired. The Sporting Arms And Manufacturer’s Institute (SAAMI) specifies that standard 9mm produce about 35,000 psi of chamber pressure.
Now, SAAMI allows for an extra 2,000 psi of chamber pressure for +P loadings.
9mm+P will typically propel a 115-gr projectile to around 1300 to 1350 fps, and produces chamber pressure of 37,000 psi.
For .45 ACP, standard 230-gr loads are booking it at about 850 fps from the muzzle and generating about 21,000 psi of chamber pressure. 230-gr .45 ACP+P loads increase that to just under 1,000 fps and 23,000 psi of chamber pressure.
You get the general idea. Slightly more powder in the case, about a 10-ish percent increase in velocity and around a 10-ish percent increase in chamber pressure. Or at least that’s what the manufacturers tell us; whether that always bears out over a chronograph is another matter.
Is it okay for your gun?
In limited quantities, meaning you’re just shooting a few rounds here and there it’s usually no big deal. While not all pistols are rated for regular use of +P ammunition, a few here and there isn’t going to do much.
Make sure you look into your specific make and model of firearm and what the manufacturer recommends as far as +P ammunition. Most will say to lay off, as it can (and will) lead to accelerated wear on the pistol.
If it’s the only carry ammo you can get, it is – again – no big deal if that’s what you load in your magazine or into your revolver’s cylinders. It’s also probably not a big deal to fire a few rounds here and there.
Where it does, however, become a concern is with regular use.
So if you found, say, a box of NATO-spec 124-grain 9mm, which is a 124-grain full metal jacket projectile, loaded to 1200 fps and 36,500 psi, which is +P or perhaps a larger lot and figured “well, it’s the practice ammo I can find right now.” In that instance you might have a problem.
If you’re going to shoot very much +P ammunition, your gun is likely going to need a stiffer recoil spring, if not some additional springs as well.
You see, the faster the bullet leaves the barrel, the faster the slide gets sent backward and the harder it slams into the back of the frame rails. This accelerates wear on the areas of contact between the slide and the frame.
By stiffening the recoil spring, you slow the slide down and therefore reduce the wear.
So the short answer is, again, a little bit is okay, but you need to do a few things if you’re going to shoot it regularly.
Now, why would a person need +P ammunition? Is so-and-so right when they say I need to have it?
The short answer is that it’s complicated.
In the Rotten Hollow Point Era, overpressure ammunition produced more reliable expansion and penetration. So in 1982, you needed it. In 2020? Not so much! Bullet technology and metallurgy has advanced to the point where it’s not as necessary.
Granted, it gets a bit more complex when it comes to one specific caliber, namely .38 Special and especially snubnose .38 Special revolvers. In that case +P is probably a good idea, but you should make sure you’re getting a short-barrel loading.
All expanding or fragmenting ammunition is, to some degree, velocity-based; below a certain threshold of velocity and the ammunition doesn’t do what it’s supposed to do. Older hollow point designs didn’t work very well at standard pressure velocities but did work once goosed with powder.
A similar trend occurred in hunting rifles in the late 50s and early 60s, which led to proliferation of medium-bore magnums. The old rotten hunting bullets didn’t work well when fired at .30-06 or .270 Winchester velocities, but worked a lot better at .300 Win Mag or 7mm Rem Mag speeds.
Modern JHP+P ammunition has no advantage in observed performance compared to modern JHP standard pressure loads. In other words, modern standard pressure ammunition will stop a bad guy just as well as overpressure and vice versa; the ammo matters less than the placement of the bullet.
Remember, all handguns do is poke holes in fleshy things when used in a defensive capacity. The speed at which the bullet pokes said hole doesn’t make a heck of a lot of difference when it comes to handguns.
So, if +P is all you can get, it’s fine. Just don’t shoot too much of it. If you have a choice, standard pressure works just as well.
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Sam Hoober is a Contributing Editor to AlienGearHolsters.com, a subsidiary of Hayden, ID, based Tedder Industries, where he writes about gun accessories, gun safety, open and concealed carry tips. Click here to visit aliengearholsters.com.