+P Cost/Benefit analysis

[clintpup]

Hey guys, I just recently came across the FAQ for AmmoLab and this caught my eye,

Is +P Ammo Better?
A. The only advantage provided by increasing the pressure and velocity of the bullet which results in an increase in muzzle energy is seen within the confines of the temporal cavity. At a difference of (+ or - 100fps) as is the case with the most standard pressure and +P (Plus Pressure) loadings our bullet does not possess sufficiently altered velocity to further stress the tissues it contacts within it's path of penetration.

In the book "Gun Shot Wounds" 2nd edition 1999 CRC press, Dr. Vincent DiMaio cites that "rather than there being a critical velocity above which the severity of wounds increases dramatically, there is instead a critical level of kinetic energy loss above which tissue destruction becomes more severe. He also notes the obvious that differing tissues have differing degrees of elasticity but he cites the median velocity for steel spheres and fmj bullets to increase this damage due temporal cavity stretch at velocities greater than 2635-2950fps. He then notes that in regards to hunting or deforming ammunition that once this critical velocity is reached the extent of destruction is the same.

Handgun ammunition does not posses the required velocity or energy to exert significant levels of kinetic energy loss in tissue to justify the requirement for the slight level of velocity increase that +p ammunition generally provides.

It's a little wordy, but it seems to me that it is saying that +P loadings do no add significantly to overall bullet performance. It does say that it effects the size of the temporal cavity though.Two questions...What is a temporal cavity? And second, does the performance of +P loadings justify their cost.

[k_dawg]

on the flip side.. +P in some calibers allows you to use a heavier bullet, with no loss in velocity.. that is a +plus in my book!

[Handy]

By the ammolab's argument, it doesn't sound like there should be a difference between 9mm and .380!


I use +P because it is what 9mm ammo is designed to work like. SAAMI standard pressure ammo is downloaded compared to the European standard, and they're the ones who invented the stuff.


But I don't practice with +P, just carry it and shoot the occasional mag. The six boxes of +P carry ammo I have will last a long time. So why shouldn't I carry it?

[Zak Smith]

Looking at the FBI gel, bare, clothed, and through barriers, the best performers in 9x19 are generally the +P loads: 127gr SXT +P+, and 124gr Gold Dot +P.

[CarbineCaleb]

I think that for the big 3 (9mm/40S&W/45ACP) a standard pressure load from Speer (who tunes their Gold Dot series well) is fine.

For the .38Special however, I think you really need the +P boost to get some decent terminal ballistics - with standard .38s, you are shy on either expansion or penetration, or both.

[juliet charley]

Looking at the FBI gel, bare, clothed, and through barriers, the best performers in 9x19 are generally the +P loads: 127gr SXT +P+, and 124gr Gold Dot +P.

If you really are looking at the FBI data, the best loads are the 147-grain standard pressure loads by Winchester (Ranger T), Remington (Golden Sabre) and Speer (Gold Dot).

So long as you are within velocity/energy for optimum performance of the bullet, it doesn't make any difference whether the round is loaded to standard, +P, or +P+ pressures.

[Zak Smith]

JC,

I seem to remember the 124-127gr-class +P/+P+ loads having better performance through barriers. I agree with you for clothed & bare gel, however.

[juliet charley]

Everything I've seen shows the 147-grain topping the 124-grain +P and 127-grain +P+ in intermediate barrier performance in everything except steel (though to be honest, there's not enough difference in any of them to make a difference--they all work well).

[BillCA]

I think juliet charley hit the nail on the head by saying;

So long as you are within velocity/energy for optimum performance of the bullet, it doesn't make any difference whether the round is loaded to standard, +P, or +P+ pressures.

To say it another way, if the bullet is properly designed and fired at a velocity at or just above which it will reliably expand, you'll get optimum performance.

The good doctor makes his point by saying that a faster bullet doesn't do much more than a slower bullet, but does not comment on the differences between one that expands and does not expand. Rather, he talks about the velocity compared to the wounds produced. Doubtless he'll have us all toting 4" barreled handguns chambered for .17HMR as the "man stopper".

[Handy]

I have to totally disagree with JCs statement. An "optimally performing" .38 Special round is not the match of an optimal .357 Magnum round.

While more extreme, this is exactly the same situation that occurs when you go to a higher velocity/higher energy 9mm round.

You don't get nothing for something.

[Netzapper]

Given optimal expansion in both cases, I would prefer to have the +P cartridge. I carry 124-grain +P ammo (Triton Hi-Vel; I have mistakenly called it Cor-Bon in the past). Something about that extra bit of kick gives me a little extra confidence.

But, all things considered, I find it very difficult to believe that a hundred-or-so extra fps will make a large enough difference to matter. I subscribe to the "penetration + wound size = stopping power" school of thought.

[mete]

Hold on !! You're not understanding De Maio's comments . He's talking about effect of velocity on human tissue ,nothing else !! He's done this with FMJs. When we get into HPs that adds things . The higher the velocity the more and more quickly the HP expands which in turn does more damage by increasing both temporal [temporary] and permanent wound channels. So the faster you drive the HP the more effective [though decreasing penetration]. So against greater effectiveness of the +P you have higher cost, more recoil [more difficult to control]more muzzle blast ,more wear on the gun. ....BTW nothing substitutes for getting good hits in the vital area.

[juliet charley]

The problem is we do not have any optimally performing .38 Special rounds in the real meaningful 21st Century sense of the word because the ammo manufacturers have not made the investment in time and money to develop one (no market--read LE market--for it).

A similar example to your .38 Special--.357 Magnum comparison where optimized rounds are available would be the current generation premium 147-grain .36 calibre loads at ~950-1000 fps in 9x19 compared to the fast stepping 125-grain .36 calibre loads at ~1350-1400 fps in 357 SIG. The standard pressure 9x19 loads have proven every bit the equal of the 357 SIG both in LE results "on the street" and in the lab. (As has the standard pressure Federal 135gr LE9T5 load.)

That being said, when it comes to the older calibres like the .38 Special, 9x19 and .45 ACP that date to the end of the 19th and beginning of 20th Century (pre-dating the "Great War"), there might be some merit in +P loads when you recognize that the SAAMI specs for these loads has to generally be safe for a 100 plus year old pistol in an unknown state of repair--this fact was recognized even the last century with .38 Special loads designated .38/44.

[Double Naught Spy]

Contrary to some of the original stuff, +P does have some real advantages. The extra 100 fps or so gives you additional range for which your round can perform. In other words, if you need X velocity for your hollowpoint to open up reliably and the round will drop below that velocity at a given distance, the the extra 100 fps will extend that distance for which the hollowpoint will open up. The extra 100 fps also has to mean greater penetration.

[juliet charley]

We are talking handguns here--and unless we are talking handguns specifically for hunting--let's not get carried away by the range thing. All the current generation premium JHPs will perform well within normal handguns ranges. Once you get beyond that anything goes. Besides, like in penetration, there are other factors in play of equal or greater importance than velocity--for example the 9x19 round I cited above handily outpenetrates the much faster 357 SIG round I cited.

This will probably be a good time to remind people that the terms "+P and "+P+") refer to chamber pressure--NOT MV. There is not a direct necessarily a correlation between a "+P" designation and velocity (and sometimes--less than ethically--the "+P" designation is more a marketing gimmick than a performance enhancer. Additives, like flash retardents, can and do impact chamber pressures

[cocojo]

Mete, your right that with hp's, the increase in velocity causes the bullet to expand fast, but at a great cost of less penetration. How can it increase the damage of the permanent cavity it the depth is less. The deeper the permanent cavity, the more damage you get. Velocity, bullet weight and hollow points, should be designed with the bullet in mind. Everything is relevant. The bullet should be designed for the velocity which makes everything work together, or in tune with each other. An expanded bullet is great but if you drive that bullet too fast you get shallow penetration. Penetration into the vitals is the most important issue here, not more velocity. Temp cavities are not that big to do that much damage. One thing I was surprised at was how small temp cavities really are. When you see them in gun rags they look big, but there not. The permanent cavity is what we are looking for here with deep penetration, the added expansion should only be a plus for the permanent cavity. One hundred feet more is really errelavant because most of your bullet designers change the bullet design for the velocity. Example look at a speer gold dot bullet designed for the 9mm in 124 grain then look at the 125 grain bullet designed for the 357 sig. Look at the hollow point depth, each bullet is designed for the velocity of the given round. Adding more velocity to a hollow point round really is too small an issue and some times it affects penetration way too much. Adding more velocity to a FMJ will increase penetration but works opposite with hollow points. I also think the best round for the 9mm is the 147 Ranger T it has it all. Weight, penetration, expansion and controlablitity.

[CarbineCaleb]

Just a few remarks:

• When there is more than one difference between expanding rounds that are not greatly different, it's not possible to understand what will happen by looking at velocities, energies, etc - you need to look at results in an experimental medium
• When a bullet strikes flesh, there is a shock wave that goes through the surrounding tissue, however, this shock wave has insufficient energy to rupture (tear) the tissue at bullet impact velocities below about 2500fps, and simply deform it elastically (push your finger into your body and let go to see elastic tissue deformation)
• Bullet expansion is the enemy of penetration - as the bullet expands, the drag increases greatly (think of how a parachute works in air) Once the bullet expands, it declerates much faster - hence control of the rate of expansion is crucial to making a bullet perform as desired
• Expansion is a dynamic process whose rate may be tuned by the ammo maker, using hollowpoint mouth size, cut size, jacket coverage, lead hardness - you cannot see these factors in a ballistics chart
• To increase penetration, you just make expansion less in total or occur more gradually using the above factors - I repeat, you cannot see these factors in a ballistics chart
• Properly conducted ballistics gelatin testing, together with understanding of the fundamental forces, are really the best guide to predicting real world performance

[Person of Interest]

This discussion will never end.

1: There is, in fact, very little difference in the damage done by the various hangun calibers. A surgeon once told me that he couldn't tell the difference between a wound made by a .38 or a .45. If bone is struck the heavier bullet has a better chance of breaking it and continuing through the target, but in soft tissue damage, no measurable difference. As others noted, it takes a rifle to really generate serious damage to a human target. A handgun, in any popular caliber, is not any sort of a "powerhouse."

That's not to say that I don't want a little velocity in my SD load. What velocity delivers is penetration and expansion. The .380 wound will look just like a 9MM wound except the 9 will be deeper. I have carried a ,380 quite a bit, but I feel better with a 9MM and this I load with Federal or Winchester 115 JHP +P+ chronographed at 1,250 FPS. In my .38s I carry 125 JHPs at 1,150 FPS.

2: Factory ballistics are variable. In the 1970s the high performance .38 loads were much hotter than current offerings. Winchester and Remington 125 +P loads are now rated at 945 FPS. I consider this to be pathetic. All factory ammo is getting slower and slower, performing well below where it could if they weren't so afraid of some idiot blowing up his Ruby and suing them. I want enough velocity to open the JHP and don't feel comfortable with less than around 1,1000 FPS at the muzzle.

[juliet charley]

I want enough velocity to open the JHP and don't feel comfortable with less than around 1,1000 FPS at the muzzle.

Bullet design and engineering has come a long ways since those days, pardner.

Depending on bullet weight and design (remember, there are more factors at work than velocity), current generation premium JHPs can deliver optimum penetration with velocities as low as the mid-800s.

[Lone Star]

When DiMaio was still in Dallas, I interviewed him for a newspaper article. The Dallas PD had just adopted the Winchester lead HP Plus P .38 Special round after extensive tests.

I have also discussed those trials with a forensic lab technician who is now with a well known ammo company.

They tested the standard round-nosed lead .38 in gelatin blocks, and determined that it was transiting the test medium while depositing only 74 foot pounds of energy in the target! The lead HP raised that to well over 200 pounds, partly due to some 150 FPS added velocity (chronographed, not printed velocities) and bullet expansion.

I strongy disagree with the forum posters who say that Plus P .38's add only 100 fps, if that, and do not perform materially better than standard ammo. I carry Plus P when loaded for defense or when outdoors where a dog or other wild animal may need to be shot.

I think that Federal's Classic 9mm JHP performs well, but still like the idea of 115-124 grain Plus P 9mm for defense.

You can avoid a lot of discussion by shooting watermelons or water-filled milk jugs with different loads. It won't be the same as shooting people, but will give you an idea of the potential energy and destructive potential of various loads.

Lone Star

[juliet charley]

Sure! That's why all the major professional and government labs use watermelons as a ballistic test material.

What a bullet does do a watermelon (or a gallon milk jug) bears no relation to what it will do to human body.

[WESHOOT2]

If velocity doesn't matter why is there a 300 KONG?

"Sufficient" velocity is what I seek.......



Just because it's on the Internet doesn't make it true.

[juliet charley]

"Sufficient" velocity is what I seek.......

Sufficient velocity for the bullet design is the key--too much is bad and too little is bad.

[WESHOOT2]

"sufficient"; yep.