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Old February 19, 2011, 09:46 PM   #1
chasep255
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What exactly are +P loads?

I occasionally see online these +P loads. I know that they mean something like extra power. However, this is a very broad definition. In your opinion where would you draw the line between +P and regular loads? Would +P be like loading the max load in your manual or going beyond that?
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Old February 19, 2011, 09:59 PM   #2
Brian Pfleuger
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+P is a max of 10% higher pressure than the published SAAMI max for the cartridge.

45acp +P is approximately 23,000psi, SAAMI max for 45acp is 21,000.

9mm +P is approximately 38,500psi, SAAMI max is 35,000.


Manual max loads are always at or below SAAMI max unless they are labeled +P. There are also loads labeled as +P+ (though not in any manuals I know of), which has no defined upper limit but is beyond +P pressure. SAAMI does not recognize +P+ loads.
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Old February 19, 2011, 10:56 PM   #3
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+P is small arms ammunition that has been loaded to develop a higher pressure than is standard for ammunition of its caliber.
There are only 4 SAAMI designations of +P and NO +P+ exist

Cartridge and Maximum Average Pressure (PSI)

9mm Luger 35,000 PSI
9mm Luger +P 38,500 PSI

38 Special 17,000 PSI
38 Special +P 18,500 PSI

38 Super Auto +P 36,500 PSI

45 ACP 21,000 PSI
45 ACP +P 23,000 PSI
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Old February 20, 2011, 02:49 AM   #4
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Here are the specs on Winchester 110gr +P+ JHP's As it says it is Treasury Dept specs not SAAMI.
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Old February 20, 2011, 08:02 AM   #5
flyboyjake
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as far as I know, some cases must be modified for +p while others do not. I bleive the 9mm case can be loaded to +p, but a .45acp needs a a case with a thicker web area designed for +p
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Old February 20, 2011, 02:57 PM   #6
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"What exactly are +P loads?"

A functional delusion, IMHO.

The velocity increase is typically equal to standing maybe 5-10 feet closer to the target and unless the target is a living troll it just beats the handgun up for absolutely no advantage. I have no need for any extra power, I'll just shoot 'em twice with a normal load!
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Old February 20, 2011, 03:28 PM   #7
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You see a lot of adds for +P+ ammo. They are most commonly designed and intended for sub-guns or rifles chambered for pistol cases.
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Old February 20, 2011, 06:18 PM   #8
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Actually, I can't recall running into any +P+ by a major ammo brand that isn't labeled to be sold to law enforcement. This allows them to lay liability off on the LE agency buying it. They assume no liability for them in that instance.

As Wncchester said, this is partly delusional, particularly for the .38 Special. And that's not just because of the limited ballistic advantage. A lot of the standard pressure limits are due to liability concerns for old guns or guns in poor condition. If you look at the CIP standard for .38 Special, it is 150 MPa (21,756 PSI) for all .38 Special loads. They have no separate +P or +P+. They just let them all go to that pressure. They can do this partly because, unlike the US, where SAAMI is an ANSI compliant trade organization with voluntary member cooperation, the CIP in Europe has some law behind its standard and is able to require every gun be sent to a licensed proof house for proofing at a still higher pressure, individually, before it can be sold in Europe.

So, the Europeans prove all their .38 Special guns are good to go with what we would consider +P+. Since I can buy European ammunition here, I quit worrying about it in the .38 Special. If I had an aluminum frame Airweight snubby, I might feel differently, but I don't. None of this applies to chamberings other than .38 Special, by the way. In other chamberings they also lack +P and +P+ categories, but the one standard they do have is sometimes below our standard. .45 ACP for instance, which they limit to 130 MPa (18,855 psi), which is below the SAAMI 21,000 psi MAP for standard pressure.
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