What's the deal with 9mm +P and +P+ ?

[50caliber123]

What is the lowdown on 9mm +P and +P+ ? I have a 9mm carbine, rated for +P+ loads, and would like to add more bang for the gun without buying a new rifle. I don't really know what the +'s and P's mean, and don't want to get jipped when I buy ammo. I can see a definite use for HD and SHTF if it really is that much more powerful. What is the best value or most powerful? Or, would I be more ahead to just buy NATO spec surplus rounds? Any comments would be appreciated, as this effects my next ammo-order.

 

[Janitor]

For calibers the spec is used on (like 9mm & .45) it's the SAMI designation for a cartridge that will reach %110 of normal round pressures. I've read mixed things on whether the +P+ designation actually exists outside the markings on some boxes. That, or it's the manufacturer saying the cartridge will reach > %110 of stock pressures.

The problem with all of this in your carbine, is that the ammunition on the shelves has been designed to be run through the short barrel of a pistol. To really get the most out of your carbine, I'm guessing you'd need a custom load. That is unless there's already a comercial load made with slower burning powders or something.
-

 

[thereisnospoon]

Wow that was a really good answer....I was going to say the difference is a +

[(+P+)-(+P)= +]

 

[Firethorn]

+P Pressure: greater than 100% of SAAMI specs, less than 110%. Official designation from SAAMI
+P+ Pressure: greater than 110% of SAAMI specs. Not officially part of SAAMI specifications.

There are carbine loadings available for 9mm & .45 that use extra powder, maybe a slightly slower powder to take advantage of the extra strength and barrel length of a carbine.

Extra power equals extra speed out of the barrel, increasing your effective range, decreasing bullet drop. Still won't equal that of a good rifle, but it'll be effective for the range most people can use iron sights for. It also increases effectivness at stopping by an unknown factor.

For effectivness, I'd use the cheapest reliable stuff for practice, and go with the +P+ stuff only for familiarization and 'serious use'

For example, from Georgia Arms, you can get 50 rounds of FMJ 124 grain NATO for $8, 1000 for $150. Rated out of their test barrel at 1150 fps.

Go to their 'shear power' page, you can find 9MM Gold dot +P+ at $15.75 for 50, $305 for 1000. This kicks you up to 1300 fps, at least in their test barrel. A carbine should get you even higher.
They have plain old +p in the gold dot, 1250 fps for $260, meaning it's costing $45 per 1000 for an extra 50 fps.

If you're that concerned about it, get a chronometer and test some small lots.

 

[thatguy]

I got a good deal on a case of +P+ Winchesters for my S&W M659. This is my daily carry piece, it doesn't get shot for recreational purposes, and all I feed it is the high performance sruff. I have clocked these 115 grain loads and comfirmed the claimed 1300 FPS. If you feel the need for max performance these would be fine for your rifle.

 

[GoBrush]

Lot's of good technical detail above good stuff. Normally I would say to stay away from it but in your carbine I think the best advice would be to seek out specialized loads for that particular set up.

I buy a ton of ammo from "The Hunting Shack, Inc." located in Stevensville, Montana (They hit the gun show's in the west)
www.thehuntingshack.com


They load special loads for state and federal law enforcement all over the country and I bet they could tell you what to buy for your carbine.

Good Luck

 

[dfaugh]

Actually, +P+ is great stuff for a carbine...I get an extra 400 fps (although I've only tried one brand, Winchester Black Talons) over most "standard" loads, so the longer barrel does seem to get you some performance advantage, at least with some loadings...YMMV...may have to do some testing to find out what really works

 

[Firethorn]

Actually, +P+ is great stuff for a carbine...I get an extra 400 fps (although I've only tried one brand, Winchester Black Talons) over most "standard" loads, so the longer barrel does seem to get you some performance advantage, at least with some loadings...YMMV...may have to do some testing to find out what really works

Is that 400 fps over rated, or over the equivalent of winchester white box?

When you're talking about firing pistol ammunition out of a carbine, pretty much all ammunition gains a fair amount of velocity. Doubling barrel length tends to do that.

Oh, yeah, in my earlier post, when I refer to 'Gold Dot', it's a premium reloader's hollow point bullet.

 

[Keith Wheeler]

Chamber pressure is the "standard" for a given chambering.
Why is it when you see 115gr and 124gr 9mm loads the 124gr is lower velocity? Well, because both cartridges will generate the same chamber pressure, so with a heavier bullet the 124gr will be slower. 147gr even slower, as in subsonic.

+P is loaded to higher than spec SAAMI here in the states (see http://www.saami.org/) or military spec. +P can usually be fired in high quality handguns, but check with the manufacturer.

The +P+ surplus you see right now (Hirtenberger) is submachine-gun ammunition. It was designed for subguns. Longer barrel, heavy bolt, longer recoil cycle than a handgun mean they can take far more pressure than a pistol. Look at the construction of an Uzi and compare it to say even a quality pistol like a Glock. Hirtenberger probably shouldn't be fired in handguns, and I'd avoid it in "junk" subguns (or their semi variants) like MACs or KG99 (Tec9). Uzis and Sterlings absolutely love this stuff.

Don't worry about the SHTF tin-foil hat paranoia. Just buy white box and leave the +P+ to the subgunners.

 

[Firethorn]

Don't worry about the SHTF tin-foil hat paranoia. Just buy white box and leave the +P+ to the subgunners.

If you looked at his post you'll see that he has a +P+ rated carbine.

Basically, the Hirtenberger is the stuff he's looking for.

 

[dfaugh]

I should have clarified:

With standard 9 mm ammo we were getting around 1150 fps out of my buddies pistol (Beretta 92FS). we tried a couple different types but I can't now recall which

Same ammo in my carbine (Hi-Point) added about 100-150 fps....

+P+ got us up to 1650 fps which is pretty zippy!

 

[Firethorn]

+P+ got us up to 1650 fps which is pretty zippy!

I'd hunt deer with it, at least at close range...

 

[Jim March]

+P+ has a bit of a sordid history.

Back when 357Mag revolvers were the standard police sidearm, various attorneys started to demonize the term "Magnum" as "evil", "babykillers", etc.



The response was to load 38Spl ammo at such high pressures it *should* have been called 357, but was in 38-length cases (just a hair shorter) so that on the stand, cops could lie with a straight face: "Oh no, we don't use those evil Magnums, we use nice mild flowery 38Spl".

These "38 +P+" were marked "law enforcement only" because they were unsafe to fire in all but a few 38Spl guns, they were really 357s and if enough got into the non-LEO community the fraud would be exposed.

A lot of the "+P+" autofeeder ammo (mostly 9mm but some 40s&w has been noted) is also marked "law enforcement only" on the box. My take: You can bet there will be private conversations back and forth between the ammo factory and the department armorers as to which loads are really safe for which guns. Not being privy to those conversations, I will not touch "+P+" for love or money, except I'd use 38+P+ in a 357Magnum gun in good shape.

Note: the lie by the cops was a response to lies from attorneys. That still doesn't make it right. They should have confronted the issue head on, instead they dodged it and we're still dealing with the consequences today.

----------

There is one very dangerous exception to the "+P means 10% over spec max" rule of thumb: 45LC+P. This is WAY over spec, meant for Ruger's ultra-strong 45LC guns or any 454Casull gun. In a decent 45LC gun like a modern Colt SAA or clone, you can drive a 255grain hardcast at around 1,000fps max - 566ft/lbs energy. 45LC+P factory loads can drive a 325grain hardcast at 1,300fps - 1267ft/lbs energy. This is WAY past "+P" in any other caliber. The rounds are often marked "Ruger ONLY!"

Worse: Ruger has recently shipped a "New Vaquero" that's smaller than previous frame sizes and is fine with normal 45LC, not at ALL fine with the monsters. Bufallo Bore has taken a positive step in saying this right on their website:

http://buffalobore.com/ammunition/default.htm

 

[Dr.Rob]

Higher pressure doesn't always mean higher speed. IE blowing out primers and stretching brass doesn't always mean downrange benefit.

You need to be VERY careful reloading 9mm as it's pretty easy (given variations in brass mfg's case volume) to create a +p+ in one pice of brass that's a standard load in another. USE ALL ONE mfg of brass.

You can find many factory 115gr 9mm loads listed as +p at 1100 fps, while Winchester lists 115gr loads at 1150 as standard.

You'll find very quickly that most (not all) +p ammo isn't any hotter than standard. It's a marketing ploy.

 

[Ares45]

As someone mentioned above there is no such animal as SAAMI specs for +P+. Which means it could be anything. 110% 115% 135%????? Proceed carefully.

 

[Keith Wheeler]

If you looked at his post you'll see that he has a +P+ rated carbine.

Basically, the Hirtenberger is the stuff he's looking for.

Yes, you are right. I lazily skipped over that and focused on the thread title "what's the deal with...". If the extra expense is worth it, it can make a 9mm carbine a hard hitter.

I'm still amazed at how many folks on THR refuse to acknowledge submachine-guns. The +P+ Hirtenberger (the L7A1 load) that's all over the place out there (ok, yes, I'm making an assumption that was what sparked 50cal's interest) is submachine-gun ammunition. It wasn't a response to anything other than the fact that a subgun can handle greater chamber pressures than a pistol. When the chips are down and all you've got is a subgun, you want it to hit as hard as possible. This is nothing new, hot loads for 9mm subguns have been around practically as long as the subgun, and have been used by the Brits, Germans, and Israelis. That's not to say there weren't some goofball things done with wheelgun ammo, and I know practically nothing about wheelguns, but most of the 9mm +P+ you'll find is for SMGs.

The Hirtenberger will chrono about 150fps faster out of a semi-auto Uzi carbine, so we're not talking magic. Nice shooting ammunition in subguns and their semi counterparts. Downside to the subgun ammo is that it's mostly FMJ. I'd rather have a decent JHP in a "situation", and remember anything worth shooting once is worth shooting again. I like subgun specific ammo in my Uzis (or I should say "our Uzis", one is mine, one is my wife's) but I am very careful not to mix it with 9mm for pistol use, so if you've also got a 9mm pistol, pay close attention to what you're shooting.

 

[JohnKSa]

Not being privy to those conversations, I will not touch "+P+" for love or money, except I'd use 38+P+ in a 357Magnum gun in good shape.

That is DEAD on the money. I will only use +P+ in a handgun if I know the pressure specs of the ammunition AND the pressure specs of the handgun in question.

...most of the 9mm +P+ you'll find is for SMGs.

That may be right for surplus, but it's not true in general in the U.S. Most of the 9mm+P+ you find in the states is LE marked.

 

[jerkface11]

The hirtenberger stuff ROCKS. Out of my highpoint carbine it rivaled .357 magnum pistol velocities. It actually had recoil.

 

[50caliber123]

Where do you find this Hirtenberger stuff? It sounds like it would make my Hi-Point carbine a tack-driver!

 

[JohnKSa]

I would contact Hi-Point and ask them about using +P+ ammo in their carbine before I went out and bought a bunch of it...

 

[Crosshair]

9mm = 87 Octane
9mm +P = 92 Octane
9mm +P+ = 105 Octane

/More power if your gun can handle it.

 

[JohnKSa]

Poor analogy...

Increasing the octane value is ALWAYS safe in a vehicle designed to operate on lower octane. The same is absolutely not true of increasing pressure in a firearm.

 

[ka50]

9mm = 87 Octane
9mm +P = 92 Octane
9mm +P+ = 105 Octane

/More power if your gun can handle it.

Higher octane is actually increased resistance to spontanious combustion in higher compression engines (thus higher resistance to burning).

Thus if you put 105 into car that's designed for 87, you'll be harming perfomance.

 

[Crosshair]

Sorry, I was not comparing 9mm to Octane in terms of safety. I was comparing it in terms of performance. Higher Octane = Higer performance provided you're engine can take advantage of it. You do not want to put +P ammo in a gun that is not rated for it. Mabee it is a bad analogy.

 

[DogWithGun]

FYI some interesting stuff

My son and I recently did a science project on baliistic effectiveness that goes right to the heart of this question. Which round is good for my carbine.

Here is a picture of a 115gr. GoldDot fired from a P226 (4.4") into balistic gelatin.


It penetrates 12.25 " (right in the sweet spot for penetration and maximum safety from overpenetration) and expands beautifully as you can see from the pic below.


Now, here's the same round fired from a CX4 carbine (16.25")



It fragments badly at the increased velocity wasting much of the potential energy penetrating to a nearly identical 12.5" but to a much lesser effect on the target.



Chrony showed an average of 1240fps from the P226 and an average of 1537fps from the CX4. Too much velocity to hold even this high quality bonded hollowpoint together.

If you are interested in maximum effect while still maintaining a level of safety choose a heavier standard load for the carbine such as a 124gr. standard or perhaps even better still the 135gr. offerings.

I would not recommend the 147gr. however because that round was developed with maximum penetration in mind and does not expand exceptionally well even at carbine velocities.





:banghead: