# Understanding +P Ammunition



## Boss Dog (Feb 8, 2013)

A question came up the other day about whether to use +P ammo. I came across this, a pretty good article on the subject. I sure someone here will find fault with something they do not agree with. Please read the whole article first. I posted the whole article here to avoid all the breaks and adds that interrupt it. 
Boss Dog

*Understanding +P Ammunition*
By: Dick Jones | December 31, 2014
Gun Digest

*Why some guns can handle the pressure of +P ammunition and others cannot.*

When discussing defensive handguns, a lot is said about calibers that are one-shot stoppers. The object of defensive ammunition is to stop the threat, and in most cases that means wielding a lethal blow to the assailant. But in reality, the concept of a pistol caliber that can reliably stop a bad guy with one shot is not possible under normal conditions.

A recent study of incapacitation data by the FBI Training Division states: "Shots to the central nervous system [CNS] at the level of the cervical spine [neck] or above are the only means to reliably cause immediate incapacitation. In this case, any of the calibers commonly used in law enforcement, regardless of expansion, would suffice for obvious reasons. Other than shots to the CNS, the most reliable means for affecting rapid incapacitation is by placing shots to large vital organs, thus causing rapid blood loss."

While a single shot to the brain has instant stopping capability, shots to the head in defensive situations are rarely the best choice.

Most law enforcement officers and civilians simply don't have the capability to make such shots reliably under the obvious stress of a life-threatening situation. As a result, ammunition for defense should be capable of penetrating sufficiently to access vital organs and generate massive blood loss. Until the 1970s, most ammunition for defensive use was the same ammunition used for target practice, training and military use.

None of this ammunition provided bullet expansion. No handgun ammunition for practical defense applications is capable of producing hydrostatic shock, which disrupts tissue far beyond the wound channel. Handgun calibers rely on penetration and the size of the wound channel. Expansion of the bullet helps, but there must be reliable penetration to get to those vital areas.

The energy produced by ammunition is what provides penetration and expansion. The more energy, the better the chance the projectile will penetrate and/or expand. In modern calibers like .357 SIG or .38 Super, all firearms available are of sufficiently recent manufacture to assure they can handle the pressures of modern defensive ammunition. This is not the case with rounds like .380 ACP, .45 Colt or .38 Special.

These rounds have been around for a century or more, and many of the guns chambered for them simply couldn't handle a sizable increase in pressure. This is why .357 and .44 Magnum rounds are just slightly longer than their non-magnum counterparts. The longer case precluded their use in older guns that couldn't handle the higher pressures.

Arguably, the first +P round was .38 Super. It's an identical case to the old .38 Auto, but .38 Super is loaded to about 36,000 psi compared to .38 Auto at about 26,000 psi. While simply changing the name of the round worked, the ammunition manufacturers needed a designation to indicate ammunition made for modern firearms engineered to handle higher pressure, hence the development of +P and +P+ ammunition.

The amount of pressure change isn't a standard percentage, but rather it's based on the individual caliber and the design of the firearms available. For instance, the pressure increase for .38 Special and 9mm Luger is only about 10 percent, but the pressure increase for .45 Colt is almost double the pressure of standard ammunition.

This is because the original .45 Colt was a black powder round, and there are a lot of very old guns still capable of shooting that round. The modern guns chambered for the .45 Colt round are almost identical to guns chambered for .44 Magnum and are capable of much higher pressures without distress.

Just because a firearm is of newer manufacture doesn't mean it's capable of handling +P ammunition. Guns designed as such will have the +P designation indicated with the caliber. The advantages of +P are obvious, but they do come with the disadvantage of more recoil and muzzle blast.

For defensive situations, more power is better, provided you can handle it. Remember, however, that if you face a life-threatening situation, you're not likely to feel the recoil, just like hunters don't notice the recoil when taking game. Normal training can be done with standard ammunition, but +P defensive ammunition will give you a better chance if you find yourself in the unfortunate situation of having to use your gun to defend your life.

This article also appeared in the January 1, 2015 issue of Gun Digest the Magazine.

Understanding +P Ammunition | Gun Digest


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## Boss Dog (Feb 8, 2013)

Some more good info links for your digging pleasure

+P Handgun Ammunition (.38 Special, 9x19mm, .38 Super and .45 ACP)
By Chuck Hawks; No Pub date Given, 2011?
+P Handgun Ammunition (.38 Special, 9x19mm, .38 Super and .45 ACP)

The inside scoop on +P
By Dan Johnson; September 24th, 2010 
handgunmags.com
Demystifying +P

And for you techies and info addicts...

SAAMI.ORG PDF file, 170 pages
Voluntary Industry Performance Standards For Pressure and Velocity of Center Fire Pistol and Revolver Ammunition for the Use of Commercial Manufacturers
1993
http://www.saami.org/specifications_and_information/publications/download/205.pdf


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## csi-tech (Apr 13, 2013)

Great info, thanks Boss.


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## rice paddy daddy (Jul 17, 2012)

Good info. 
I only have one issue - the 38 Super is not a "modern round" like the 357 Sig. The 38 Super was designed in the early 1930's for law enforcement, the theory being it would have enough power to disable an automobile. The 357 magnum, introduced in 1935, had more power but the 38 Super in a Colt 1911 held more rounds and was faster to reload. One of the Feds who took down Bonnie and Clyde used a 38 Super.
I have always wanted one, and if I ever buy another handgun it will be a Rock Island Armory Government Model in that caliber.

I am a regular reader of Handloader Magazine, and a number of years ago they had an article on 38 Special +P ammo comparing modern +P loads to those standard pressure loads listed in reloading tables from the 1960's.
The question that caused the article was a reader asking if his 1960's and 70's S&W 38 Special revolvers could safely fire +P. Turns out they can, because the standard pressure loads of that era are actually the same pressure as modern +P.
NOTE: this only pertains to 60's and 70's S&W 38 Special revolvers.
I keep my Model 15 K38 Combat Masterpiece loaded with Winchester +P 158 grain lead semi wadcutter hollow points, commonly called "the FBI load." But no way would I let my wife put those in her Charter Arms 38 snubnose.


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## Notsoyoung (Dec 2, 2013)

If the manufacturer of your pistol says "don't use +P ammo" in the pistol, then don't use +P ammo. Simple as that.


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## sideKahr (Oct 15, 2014)

rice paddy daddy said:


> I am a regular reader of Handloader Magazine, and a number of years ago they had an article on 38 Special +P ammo comparing modern +P loads to those standard pressure loads listed in reloading tables from the 1960's.
> The question that caused the article was a reader asking if his 1960's and 70's S&W 38 Special revolvers could safely fire +P. Turns out they can, because the standard pressure loads of that era are actually the same pressure as modern +P.


My understanding is that ammo manufacturers today do not want the liability of people using +p in old weakened revolvers, so they have reduced the power of ALL the loads. Applies mostly to .38 special.


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## rice paddy daddy (Jul 17, 2012)

sideKahr said:


> My understanding is that ammo manufacturers today do not want the liability of people using +p in old weakened revolvers, so they have reduced the power of ALL the loads. Applies mostly to .38 special.


This is also true for 45/70, in case it ends up in an old Springfield Trap Door. And 8MM Mauser, because before 1898 the bore diameter was .318, in 1898 it changed to .323 so American manufacturers load low enough pressure to not blow up the older rifles.


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## ApexPredator (Aug 17, 2013)

FBI Whiz kids forget pelvic shots nothing says incapacitated like a shattered pelvis


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## wallyLOZ (May 12, 2013)

Some good research there, Boss Dog. Thanks!


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## alterego (Jan 27, 2013)

I have some 2-1/4 ounce nitro magnum 3-1/2 inch 10 gauge rounds for my favorite gun to incapacitate. Do you know if these are considered +p rounds.
I believe they would make you +P if you were on the receiving end.


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## rice paddy daddy (Jul 17, 2012)

ApexPredator said:


> FBI Whiz kids forget pelvic shots nothing says incapacitated like a shattered pelvis


When I took some training courses put on by our local LEO's 15 years ago the instructor said many police academies were going to the pelvic shot because that was the fastest way to achieve a "stop" using a 9MM on an advancing perp.
He recommended we do the same if using a 9MM or less.


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## 1skrewsloose (Jun 3, 2013)

I haven't done the research, but, wonder what Mas has to say?


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## Notsoyoung (Dec 2, 2013)

ApexPredator said:


> FBI Whiz kids forget pelvic shots nothing says incapacitated like a shattered pelvis


It is physically impossible for a human being to walk with a broken pelvis. It's not an instantaneous killing shot, but it will stop them from walking towards you.


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## AquaHull (Jun 10, 2012)

I'm not buying into,nor buying any more +P ammo. I don't believe it's needed. A lighter load can give you more practice, better groupings, more confidence.
Train the way you fight comes to mind.

I'm not switching until all the 124 gr Speer GDJHP +P's are gone though.


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## rice paddy daddy (Jul 17, 2012)

The only 9MM I own can only handle standard pressure ammo. Walther P-1, which is a post war alloy framed P-38. But that's OK because it is just a shooter.
Now, my New Model Blackhawk carries Corbon 45 Colt +P 200 grain JHP. 'Cause sometimes things need to be DRT (dead right there). And as any old hotrodder knows There's No Replacement For Displacement.


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## AquaHull (Jun 10, 2012)

http://images.thecarconnection.com/...cers-image-chrysler-group-llc_100368736_m.jpg


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