Does anyone know if there is a real difference between standard velocity and +P 9mm ammo in a 3" barreled semi auto?

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Foster Positivity.

Assuming you're talking about self defense purposes, +P may give a slight advantage in gel, but I doubt there would be much of a difference in the real world. My preferred SD 9mm load is standard pressure 147gr HST and I wouldn't hesitate to use it in a short-barrel gun.

A 3" auto drops off fps very fast from a 4 or 5" barrel.

It is almost impossible to get a +P speed out of a 3", even with reloads.
You also need a load that you can handle and shoot well, if possible.

I could reach +P in my 3.5" C9 but in a Kahr 3" I could only get
a 115 ball to 1168fps and a 124 ball up to 1118fps

I never got to test the 147 HST in this 3" pistol but it might be my choice
with the heavier bullet, that is slow any way.

Even with +P ammo, you will be actually shooting a "Standard" load......
out of a 3" barrel, from what I have learned in my test.

Good shooting.

is +P considered the fps or the pressure it generates?

I always assumed pressure, the fps was expected but generally fell off the shorter the barrel - all depending on powder burn...

+P refers to the pressure of the loading. Read the SAAMI page for more info on what the designations mean.


As to the OP's Q: that will depend on the individual gun and the individual load. While it is difficult to figure out what's an apples-to-apples comparison, I have found there's not always much difference between the velocities delivered by very similar loadings (same bullet, same maker) of standard or +P designation.



For instance, out of my 3" SIG-Sauer P938 (Range at 5950’ > sea level, c. 73°F, c. 45% humidity), Remington's standard pressure 124-gr Golden Saber BJHP did 1056 fps/61.29 spread/23.28 deviation



and the +P variant with the same bullet did 1114/20.02/12.76. In that little, light gun, I'm carrying the standard pressure variant.

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Now go make God proud...

You are correct, the P in +P does stand for the word Pressure

Everything else being equal, more pressure will give you more velocity

The SAAMI +P designation indicates that this round of ammunition is loaded above industry standards

So if you have two identical rounds from the same manufacturer one being standard pressure and one being +P, the +P round will always leave the handgun barrel faster than the standard pressure round.

It does not matter what handgun we are talking about

The question should be, is the gain received worth the extra wear and tear that a +P round imparts on the firearm over a standard pressure round of ammunition

In my teeny, tiny polymer framed 9MM pocket pistol, I always carry standard pressure ammunition. If I am carrying a slightly large metal framed pocket or personal pistol I will usually carry the +P offering

Nowadays +P is only a marginal improvement over a good standard load by the most common manufacturers.

But, the manufacturer should specify whether a particular gun is suitable for +P. Many small 9mms are standard only. If your gun is suitable for +P, it's a matter of preference. Yourdefense ammo like Federal HSTs, Speer Gold Dots, Remington Golden Sabers and the like all perform well with a standard load. If you can get a little more velocity with a +P and you can handle the recoil and the extra expense, go ahead.

PS: Speer makes special 'short barrel' ammo for short barrels that are designed to expand at lower velocities. It's good stuff, but so are the others that I mentioned.

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"He was kinda funny lookin'"

ContinentalOp hit it right on the head. I carried a BHP for over 40 years and the 147gr. standard is a great load. Totally adequate. The difference between standard and +P is mostly negative--greater recoil, noise, muzzle blast, and more difficulty getting on target for the follow up shots. Any type of shooting outcome is 100% dependent on proper placement of the shot onto the target.

Try several ammos and bullet weights/styles, +P and standard pressure. Use what does best for you in your gun; the pressure designation matters not.

+P, the latest bullet style, etc. is more gun article, gunfighting theory, and Internet forum-oriented than something really useful. Hitting what you aim at consistently is far more important than all the other.

Thanks all.
I asked because my favorite lawyer (I tell him that's an oxymoron) says it's easier to defend me successfully if I shoot an auto instead of the revolvers I usually carry, mostly because I've tuned the actions. I just bought a Sig P365 with 10 and 12 round mags that is +p rated and if it shoots well and consistently the Js will probably end up in the safe. Doesn't seem to me that +P is worth the muzzle flash and it seems you all agree. Only have 75 rounds thru it but without any issues. I'll go for 400 before I carry it. Thanks again.
Joe

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Foster Positivity.

If you believe the stats at Ballistics by the Inch, +P loads will give you a 100 foot pounds of energy advantage and as much as 250 higher muzzle velocity from a 3 inch barrel as opposed to standard pressure rounds.

If you believe Lucky Gunner results, the Federal HST 124 grain standard pressure and the +P round have the same velocity and energy from a 3.5” barrel, with the penetration advantage median depth going to the standard pressure round.

An excellent summary, in addition to adding "100% reliable feeding and function". Fast accurate hits are the key...

For the record, 9 mm standard SAAMI pressure is 35000, and +P 38500 psi. Whether ammo is loaded to full spec for either category is often an open question.

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Alan
SWCA LM 2023, SWHF 220

I wonder why a 12 round auto would be "easier to defend" than a 5 round revolver in a trial. I wonder if the handgun of choice has ever been the subject of analysis in a trial where use of a handgun was found justifiable.

I know that Bernie Getz was considered to be legally justified ....not guilty of attempted murder, assault, etc. ....in shooting 4 men with his 5-shot revolver. Of course, he got prison time for illegal possession of a firearm that a jury decided he had not used incorrectly.

I guess if the world made sense, cowboys would ride side-saddle.

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Carry.."hope" isn't a strategy

Has to do with the prosecutor trying to prove the gun was fired negligently because it was modified and could be fired single action (hair trigger).

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Foster Positivity.

Again, getting into conjectural gunfighting theory; pretty much a wasted effort, but a subject some obsess over. No two situations are the same.

To help answer the OP's question, no. If you have a 3" barrel 9mm then the difference with +P over standard pressure will be negligible. There is a certain threshold in barrel lengths when 9mm gets to a certain velocity when a HP performs as it was designed. Paul Harrell on his YouTube channel has clearly demonstrated there is a huge difference in FPS between a 3", 3.5" and a 4.9" 9mm barrel using the same bullet. A difference of like 90fps more in a 3.5" barrel over a 3" barrel. That is a BIG difference.

he mentions that in the middle of this video

My standard 9mm competition load is 124gr FMJ over 4 gr Titegroup.
It chromos PF 120 in my Shield, PF128 in my 4 1/4" M&P and PF 133 in my 5" M&P. Notice that does not follow any of the "General Rules."
Until you chrono the loads of interest in YOUR gun, you don't know squat....no matter how much fun it is to guess.

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Science plus Art

I like 147 gr bullets in my P938. It's pleasant to shoot.

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I've still got it made.

With modern bullets, I have become a fan of the 147 grain JHP in 9x19mm. I've tried standard pressure and +P loads in a S&W 6946, S&W 439, and a TZ-75 Series 88. There is definitely more recoil and muzzle flash with the +P loads and based on ballistics gel results published by Federal, Winchester, and others such as TNOutdoors9, I don't think the +P has much, if any, advantage over standard pressure loads. For me, the extra recoil, which means accelerated wear on the firearm, and flash in a compact pistol is not worth a tiny gain in velocity. For years I have carried the Winchester Ranger 147gr T-Series JHP load, I expect to soon transition to the Federal 147gr HST load, both standard pressure.

You need to find another attorney. That one clearly doesn't have a clue about shooting cases.
What this "attorney" is saying is you use your firearm in a self defense situation and the prosecutor is going to argue that you did not intend to shoot the person, it was an accident because your firearm had a light trigger. That makes absolutely no sense. No prosecutor is going to argue an accidental shooting if you're saying you were in fear of your life and the use of deadly force was justified. Find another attorney.
The question is did you intentionally shoot the person. Trigger pull weight has nothing to do with it. If you did not intend to shoot the person then it doesn't matter trigger pull either. The question in shooting cases is would a reasonable person believe they were in fear of their life or great bodily harm where the use of deadly force is justified.
If you say you didn't intend to shoot the person then trigger weight won't matter either. At trial it's either you were justified using deadly force or you weren't.

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183rd FBINA

As many have said, I leave my 3.8" XD loaded with 147gr standard pressure Ranger T loads.

I have run +P rounds through my two pistols (3.8 and 4.5") and they are hotter for sure, in the "notably hotter" range are the +P+ rounds like the Ranger series and the Federal 9BPLE round.

I just ran some of the 9BPLE through my XD sub last week and I can assure you, the recoil difference is notable.

Interesting comment. I suggest folks read Massad Ayoob's commentary (sticky) on this subject in the Self Defense forum. Lightening a trigger on a SD gun is just one more arrow in the quiver of a prosecutor or civil case. While your attorney may win eventually why arm the prosecution? Ayoob has the experience and reputation to know what he's talking about. Just no reason to lighten a trigger below the manufactures recommend minimum pull, IMHO, on a SD gun.

If the shooting and injury was justified, this is a nonissue. If the shooting and injury were not justified, it’s still a nonissue. You’re either no billed or paying the piper for shooting someone you shouldn’t have. I have never had a negligent discharge with a standard Glock issue or a Glock with a 3.5 lb connector, but I’m pretty sure the penalty would be the same either way as there are not separate laws and penalties for each.

The issue in a prosecution is whether the use of deadly force was justified. If you are charged and admit you shot a person because you were in danger of death or great bodily harm then the prosecution sure as heck isn't going to argue that "no you didn't really mean to shoot the person, it was an accident." That argument makes absolutely no sense. Think about it. Anyone with a lick of common sense and reasoning will see the fallacy of thinking the prosecution is going to argue an accident. If a person doesn't see the silliness in that argument then they've watched too much TV and believed too much internet BS from those who don't know.
If the use of deadly force is justified then it doesn't matter if you shoot them or hit them with a 9 iron. You're protecting yourself from death or great bodily harm. The instrument you use is irrelevant. It's the act and whether it was justified.
The only time a light trigger may come into argument is if you say you never intended to shoot the person, you had no justification to defend yourself but because of the light trigger the gun went off when you did not intend for it to fire. The issue in that case is even bigger. You used deadly force when none was justified nor intended.
Been thru enough actual shooting investigations. I didn't get my facts from reading books or other people's reports.

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183rd FBINA

Manslaughter is manslaughter regardless. You killed someone without intent or malice. Trigger pull weight is irrelevant to the crime and punishment.

As stated in other's comments if your justified the condition of your gun really doesn't matter. A prosecutor would have to somehow have to convince the jury that your "trigger job" somehow made you decide to murder someone. Ayoob is a long time gun writer, part-time cop in a very small town in New Hampshire, a competitive shooter who uses highly modified guns, that has become a court recognized expert. He is also the one who says not to use reloads or guns with bad names but will also tell you you can't go wrong by carrying what your local PD carries.

All my revolvers have at one time or another had some trigger work. They are smoother and as such feel lighter but all springs are stock.

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Support your Police, & NRA

Yep, I love modern bullets. Full metal jacket with some meplat.

Speer Lawman is my favorite.

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I've still got it made.

I am not an internet expert, also I am not into self marketing. Have never missed a snake with a 357 sig, and the snake still died from concussion. So my word is not worth much. Pick the ammo that makes you feel the most comfortable, as long as it is safe. Make sure you can hit CNS with that round, and the rest does not matter.

As has been repeated many times justified is justified. Internet experts, and self marketing experts are not the ones who are going to save your butt.

My wife is right. I should shut up and stop explaining myself because I end up doing what I want anyway.
Buy the way, I put another 100 rounds (standard) thru the P365 today without incident and I really like it.

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Foster Positivity.

...off the top of my head but I know that out of a short barrel the difference is about 20 fps maybe a little more but not much. I reload and I've tried to reach better velocities compared to good factory ammo. In a short barrel you can add bang and recoil but it doesn't get that much velocity. You can pack in the powder and the reward is small. More important may be just having a round that isn't so raucous that you can hold and shoot follow ups better.

I have some small guns, especially an alloy .38 that is uncomfortable to shoot standard and downright painful to shoot +P out of.

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"He was kinda funny lookin'"

Fascinating how a thread about ammunition pressure ends up being a discourse in the potential legality of altering trigger pull. LOL!

No deal breaker,less than 100fps difference. Makes no Nevermind.

Welcome to the Internet.

Always nice to know that your ammo will cycle in your weapon
without any problems.
The type of ammo used is the big question.
Do you want a JHP bullet to expand and penetrate at 3" barrel speeds?
There is also a heavy mass for deep penetration with or with out expansion.

Lots of bullet study is needed and maybe some water jugs are
in the works, for a final decision on your 3" SD selection.

A 3" can work but it is one reason I moved up to a 3.5" 9mm pistol......
for the Speer GD ammo with a copper jacket .
My 3.5" with the Speer #23611 Short Barrel +P ammo gets 1124fps.

I don’t feel much difference at all in recoil between standard pressure, +P, or +P+...they all just feel like 9mm to me.
My Glock 26 is loaded with +P 147gn HST, which it shoots very well.
Previously, my favorite 9mm load was the Ranger +P+ 127gn load. I shot this in many different nines over the years, HiPower, 92FS, Glock...
I just haven’t seen any for sale for a while.

So remove single action capability. S&W did make DAO only hammers for some of their guns. All/most of their parts went to Numrich, check for them or Jack First. Or, have the hammer or trigger reworked-the hammer can be screwed up by someone who thinks they know what they're doing, causing DA isues.

To P or +P.......there's enough brand to brand/lot to lot/product line to product line variation in velocities that you really need a chronograph to figure out what you are getting out of your firearm with any given brand/lot. From what I've seen, most +P loads tend to deliver ballistics closer to what most makers claim for their standard velocities. There are exceptions.

Some smaller pistols have slide velocity/feeding problems with one type or the other. This is something you learn by trial and error, guided by the owners manual.

As some have noted, some smaller pistols are distinctly unpleasant and/or inaccurate in your hands with +P. Again, trial and error.

Finally: the most important item in self defense is bullet placement. Looking for magic bullets is time better spent on practice.

Prosecutor: "I contend that in choosing to shoot your gun single action the hair trigger caused you to shoot my client."

Defendant: "I contend that either way I was intentionally going to shoot your client."

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"He was kinda funny lookin'"

Prosecutors have clients?

He's sort of combining criminal action and civil suit. Self defense is a 3 point problem, first survive Micky the mugger, do it in a manner that keeps the prosecutors office happy and then deal with the civil suit.

It's not unknown for prosecutors to allege a cocked gun/negligent discharge, this sets you up for aggravated assault (or whatever in your state) or manslaughter. [Of course you're claiming self defense, you're trying to cover your butt over your criminally negligent gun handling!] It's fairly common practice in a civil suit. Negligence increases the damages.

It's conversation.

It was the OP who introduced the topic of legality in a second post.

How many conversations that start out with comments on the weather eventually go elsewhere?

All of them, I hope.

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Carry.."hope" isn't a strategy