please explain "+P"

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RudeBoy

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Can someone explain what exactly "+P" means regarding bullets? Thanks for answering what I know most think seems like a pretty basic question. I know that it's a more powerful load, but how and why? What's their history?
 
Cartridges are loaded to a specific pressure range. Some cartridges are loaded to a pressure higher than what is standard. These are called +P ( or extra pressure) loads. The extra pressure increases velocity. The most famous is the .38 spl loads as the .38 spl in a short barrel revolver can be rather anemic. The +P loads creates more velocity which gives the short barreled revolvers a boost in performance.
 
gotcha

I had thoughts in that direction, then today while looking at a 38 the fella behind the counter said "+P refers to the 'partition' in the hollowpoint," meaning that little post in the middle of the hollow point tip.

I have 32 defense rounds for my Tomcat with that post, which I didn't think were "+P" since they didn't say so on the box. What function does that post perform?

;)
 
Everything standing behind a gun counter is not an expert. That fellow doesn't have a clue as to what he's talking about. +P concerns the cartridge not just a bullet.
The post in the Federal Hydrashock rounds helps the bullet to expand. Bullets expand using hydraulics. The post being in the middle of the cavity helps direct the fluid entering the cavity towards the outer surface of the cavity allowing pressure to build to force the lead to break the jacket and mushroom outward.
 
If I had a nickel for everytime I heard good advice from someone behind the counter at a gunshop, I might get a cup of coffee and none of that fancy Starbucks stuff either. Majic told you true on this one. Actually +P is a designation given by SAAMI (the guys who make ammo guidelines for manufacturers) to specify a cartridge is in a certain range which actually makes it a new cartridge in its own right, for example a .38spl +P is only to be used in guns made to handle it and approved by the manufacturer for its use. You shouldn't use +p ammo in older guns not made for it, and be very sure of your weapon if you come up with any +P+ rounds such as some 9mm rounds.
 
And to add to what the others have said you'll also encounter +P+ which means even more pressure, a number higher than SAAMI spec. If its a manufacturer you trust to know what they're doing that doesn't necessarily mean its unsafe, but since there is no spec for it someone might be going overboard..... Sometimes you'll also find a manufacturer calling their ammo +P when that caliber doesn't have a +P standard. I've seen this in .380 before.

Here's a list of some pressures to give you an idea
http://www.handloads.com/misc/saami.htm
 
Only if you have similar point of impact.

If you can't hit what you're shooting at, it doesn't matter what you're shooting with.

john
 
The Sporting Arms and Ammunition Manufacturers Association (SAAMI) sets the standard for maximum allowable pressure for each type of round. That way the manufacturer of a gun knows what pressure he has to design the gun to handle and the ammunition manufacturers know the maximum pressure they can load to. However, standards are just what their name implies. While they provide the confidence that it is safe to fire a particular round in a gun that it made for it (for example you should be able to safe in firing a .38 Special round from a gun designed for and marked .38 Special) it's also possible to build a gun that is stronger than the standard. However once the "standard" limit is exceeded there needs to be a new standard set to again establish a safe pressure limit if anyone other than the original builder is ever going to make ammunition for it.

So, specifically, "+P" allows for a 10% increase in pressure over the normal SAAMI limits for that round. So, for ammunition, the pressure generated by the +P round should be over 100% but no more than 110% of the SAAMI standard. A gun that is designed to be safe at pressure levels generated by firing +P rounds will be marked +P after the caliber marking on the barrel. A gun that is not marked +P is NOT designed for overpressure rounds and is NOT safe to fire +P rounds.

I haven't done any direct work with SAAMI in several years but the last I knew +P+ (Plus P Plus) was not recognized by SAAMI and was simply a marketing device. Hopefully +P+, which implies higher pressures than +P, is still below the +P 110% pressure limit.

Tom
 
The XD40 I had was not marked on the barrel for +P's so I called Springfield and asked them if I could shoot +P+ out of it and they said yes.
 
The XD40 I had was not marked on the barrel for +P's so I called Springfield and asked them if I could shoot +P+ out of it and they said yes.
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The last I knew, SAAMI had not established a +P for .40 S&W (it's done on a round by round basis) so no manufacturer would be marking a barrel for it. However my information is a few years old, and .40 has become a lot more popular since then, so it's possible that there is now a +P for it. Offhand I just don't know of anybody actually making .40 S&W +P ammo.

I can say it wasn't the lawyer's turn to answer the phone at Springfield that day. :eek: I think if you sent a blown up XD40 in to them for warranty repairs with the remains of a +P brass jammed in the chamber you'd find that your telephone conversation wasn't worth the paper it was written on.

Tom
 
I've never seen a gun "marked" +p. Would like to see a photo of such. Glocks, for example, certainly are rated for +p, but there's no "mark" to that effect on a Glock. Same is true for the XDs and just about every other +p rated handgun.
 
If you call S&W they'll tell you whether or not an older revolver is rated for +P. Unfortunately, the only revolvers I have that are rated for .38Spl +P are .357 Magnums :)

BTW, Georgia Arms manufactures .40 S&W +P and +P+
40 SMITH & WESSON GOLD DOT
G40B 155gr Hollow Point +P 495 1200
G40F 165gr Hollow Point +P 443 1100
G40C 180gr Hollow Point +P 440 1050
G40+P+ 155gr Hollow Point +P+ 581 1300
 
Ruger had a run of SP-101's in .38 marked +p

Higher pressure doesn't always result in higher speed.

Look at the ballstics charts for a variety of ammunition mfgs... you'll find what SOME call +p, others call 'standard.

Again, the magic of marketing.

The spike in pressure does make a difference in your gun and unless your manual says +P rated, don't use it.
 
On a more mundane note, they can make a really big flash (powder still burning as it exits the barrel I suppose).

I had some Hornady .45 ACP +P that I was glad I tried at the range because if I tried to use them as a HD round I'd be half-blinded by the flash.
 
A gun that is not marked +P is NOT designed for overpressure rounds and is NOT safe to fire +P rounds.
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I don't see any +P marking anywhere on all my HK's, but it is written so in the manual that it's okay to use +P in my USP9, USP45.
 
gudel said:
I don't see any +P marking anywhere on all my HK's, but it is written so in the manual that it's okay to use +P in my USP9, USP45.
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Same with the Sigs. They state in the manual that +P ammo is acceptable for use in their pistols (aka doesn't void warranty), but +P+ is not. My guess is that as stated eariler +P+ isn't a standard so much as a marketing device. +P is a defined objective standard.

But I don't worry about it because I carry 125grn 357 Sig Gold Dots in my P229. :p
 
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I had thoughts in that direction, then today while looking at a 38 the fella behind the counter said "+P refers to the 'partition' in the hollowpoint," meaning that little post in the middle of the hollow point tip.
Click to expand...

Bwaaaaaaaa, ha, ha, ha, ha! That's the best one I've heard yet by a gun shop guru!:D Jeez, glad they don't require intellegence for the job, eh?
 
the fella behind the counter said "+P refers to the 'partition' in the hollowpoint," meaning that little post in the middle of the hollow point tip.
Click to expand...

So what would +P+ mean? Would it mean that there are two partitions?:D
 
The reason for the title +P+ is for Winchester. Since regular Winchester loads are around 830fps for hardball 230gr and 880fps for the personal defense JHP. This makes the JHP a +P round for Winchester and 950fps would be a +P+ even though by Official rating... it is a +P
 
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