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Old 03-30-2022, 08:40 AM
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Default Interesting, and factual, article about +P Ammunition

For all of you who keep asking "Is +P safe in my XYZ pistol/revolver?", A very interesting and accurate dissertation on +P ammunition. This was posted on the internet by Alien Gear Holsters a couple of years ago. It thoroughly discusses exactly what +P ammunition in comparison to standard pressure loads and proof loads! It condenses what has been published in various print sources ever since the +P designation was originally created, about 40 years ago as I recall. Do yourselves a favor and carefully read the entire article, instead of reaching a conclusion after just the first few sentences! Here is the link: Is +P Ammunition Safe? What You Need To Know About Overpressure Ammunition
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Old 03-30-2022, 09:13 AM
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Well written article. Thanks for sharing it.
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Old 03-30-2022, 09:13 AM
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Thanks .... good read!!

When I was young and dumb I believed in the "One shot stop" from a 125gr .357 semi-jacketed hollow-point.... and a good chance with a .45 200gr "flying ashtray"

Older and I hope wiser .........I'm no longer a true believer in the "one shot stops".... I'm a believer in a well placed........ "double tap"!!!

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Old 03-30-2022, 09:25 AM
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Good article. Well worth the time.
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Old 03-30-2022, 10:09 AM
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What they said.

Worth the short time to read.
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Old 03-30-2022, 10:41 AM
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An inconsistency appeared in the article, which I found quite informative. According to the author, +P pressures are set by Sammi at between 2,000 and 3500 psi above standard pressure. In the article the 9mm standard pressure is 34,000 psi but the +P pressure is 38,000. 4,000 psi is above Sammi standards.
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Old 03-30-2022, 11:06 AM
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Quote:
Originally Posted by 30-30remchester View Post
An inconsistency appeared in the article, which I found quite informative. According to the author, +P pressures are set by Sammi at between 2,000 and 3500 psi above standard pressure. In the article the 9mm standard pressure is 34,000 psi but the +P pressure is 38,000. 4,000 psi is above Sammi standards.
He did say, "generally"...
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Old 03-30-2022, 11:07 AM
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I don't think its such a great article. It claims that because guns can take proof loads on rare occasions, the author seems to insinuate that guns that can handle a tiny handful of proof loads in their life can handle a steady diet of them. This isn't true at all.

Proof loads are meant for one time testing for new guns, or another one time testing for some armory repair jobs. Overloading a gun for a test drive is a long standing tradition going back to the earliest days of gun making, and we should understand the purpose and background of what it is and what is. Also, what it ISN'T.

Guns need not only survive one test shooting, but safely fire tens of thousands without any metal fatigue that could lead to failure. This is why SAAMI standards must be followed, and not cheated.

The fact a firearm or barrel can handle a proof load is no proof that a steady diet of those rounds will not destroy the barrel, chamber, gun from constant repeated use. Indeed, many chambers, barrels, actions, guns fail from abusive constant use of hot rounds, not single overcharges. The reason why SAAMI keeps those proof test numbers almost secret and not published openly is because these numbers are never meant as a base standard for MAP for reloaders or ammunition manufacturers. In fact, the proof test load has NOTHING to do with what is safe +p pressures for a firearm. The fact that a hot round is less than the test proof charge means absolutely zero, because it not some sort of secret hidden highest MAP allowable, thus +p cannot simply be "OK because it is less than a proof charge, hurr hurr".

No mention of older firearms, prewar steel, some guns of lesser construction, and the fact many SAAMI standards are focused on pressures that are safe for all guns for that caliber, not just new ones. No mention of old 38 Special revolvers, weaker designs, ect. The author seems oblivious to these important facts and history as well. +p 45 ACP in an original 1917 is extremely bad advice, not just a little extra wear and tear. Many other examples can be made.

The author makes no mention of auto loaders and cycle times. Guns are made to cycle at a certain speed, and with higher pressure loads in some guns, they can cause catastrophic failure, and not just the type of Glock failure he mentions. If the bolt operates before pressures drop safely, this can cause a massive blow up. Hot rounds often both increase slide velocity and pressure, leading to the potential for a dangerous failure if things are off enough. Not just battering slides, but other dangerous concerns.

And what of the author's claims that revolvers were seeing chamber warping due to full power magnum loads? Isn't that 100% bogus? The failures of K frames is in the frame, not the chambers, and any failure in medium frame magnums would be the same. He claims that 44 Magnum S&W would see chamber damage, when how many hotloaders who shot steel only talked about damage to the internal parts from abuse, but never wrecked a frame or a cylinder in the process?

This is a terrible article, written in poor style, missing important key elements, and making dangerous assumptions about proof test loads and SAAMI limits and spreading this dangerous information publicly. It should be revised or removed.
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Old 03-30-2022, 11:20 AM
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Informative and it enforced my practice in CC ammo, if using inferior bullets faster is better as is a bigger (heavier) bullet.
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Old 03-30-2022, 11:37 AM
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After twice reading this article I found no mention of the fact that some semi-automatic pistols are specifically described by the manufacturer as being designed with the sustained use of +P ammunition in mind...?

Just a comment.

Cheers!
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Old 03-30-2022, 12:10 PM
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I generally stay away from over pressured rounds. If I want more power I use a more powerful caliber.

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Old 03-30-2022, 12:10 PM
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A few years ago I did a lot of research regarding +P ammunition as well as overpressure loads in general. Ultimately, I reached the conclusion that +P ammunition has no practical use because it just doesn't result in nearly enough of a performance boost to justify the extra pressure and accelerated wear on the pistol that it's fired from.

Basically, if Standard Pressure ammunition isn't powerful enough to suit your purpose, then neither is +P, and you need to upgrade to a more powerful cartridge than try to turn an existing cartridge into something it's not.

The only cartridges which I would consider to be exceptions to this rule are .38 Super Automatic +P and .45 Super Automatic, simply because .38 ACP is long out of production, the +P designation was only added to further illustrate that it wasn't safe to shoot out of an old .38 ACP Pistol, and .45 Super actually does use a different case than .45 ACP, even if the external dimensions are identical.
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Old 03-30-2022, 01:11 PM
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Quote:
Originally Posted by Forte Smitten Wesson View Post
A few years ago I did a lot of research regarding +P ammunition as well as overpressure loads in general. Ultimately, I reached the conclusion that +P ammunition has no practical use because it just doesn't result in nearly enough of a performance boost to justify the extra pressure and accelerated wear on the pistol that it's fired from.

Basically, if Standard Pressure ammunition isn't powerful enough to suit your purpose, then neither is +P, and you need to upgrade to a more powerful cartridge than try to turn an existing cartridge into something it's not.

The only cartridges which I would consider to be exceptions to this rule are .38 Super Automatic +P and .45 Super Automatic, simply because .38 ACP is long out of production, the +P designation was only added to further illustrate that it wasn't safe to shoot out of an old .38 ACP Pistol, and .45 Super actually does use a different case than .45 ACP, even if the external dimensions are identical.
+P probably has it's place, but it's a very small niche. Agreed the difference between it and standard pressure loads is often less than significant. However, if +P ammo in a particular gun was considerably more accurate than standard pressure loads (big "if"), I'd probably go with +P.

Many today, however, seem to treat the +P designation like they do a light trigger in a handgun or long gun or a high magnification scope on a rifle: it's a shortcut to shooter skill or takes the place of shooter skill altogether. Regrettably, it doesn't work that way.
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Old 03-30-2022, 05:25 PM
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I see no problems using +P ammo in moderation in one's guns, if needed.

I do however think that the companies that make +P ammo can contoll the amount of high pressures
by the type and burn rates of the powder that they use in their ammo,

Take for example the 357 magnum with a 125 gr. JHP bullet.
Below is a sample of what I have used for a medium load but some loads
are near a maxium load for some powders and some are still asleep.
w231 at 8.0 grs........... 1225fps
Unique .. 8.0............... 1285
Blue Dot 11.0 ............. 1288
imr4227 .. 18.5c ......... 1230

A full load 124 can be as high as 1450fps with the right powders.

I am just saying that there is +P ammo and there is, +P ammo !!

There are only two companies that I buy 110% ammo from.
Good shooting.
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Old 04-02-2022, 12:03 AM
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Yes, thanx for the link. Meanwhile I will say that I use some +P ammo and load some as well. I see no harm in having a 50rnd box of +P ammo to go with your HD firearm if it is one of the calibers available in +P...........
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Old 04-02-2022, 12:27 PM
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Great comments! I really enjoy this forum!
In the late 60's I got a S&W model 19. Shot Super Vel ammo and have never looked back!
I carry HST in my 9mm and Precision One ammo in my 380 M&P Bodyguard, both non +P.
I do shoot Speer Gold Dot 124gr+P and 124gr NATO ammo on occasion in my 9mm from time to time.

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Old 04-02-2022, 05:31 PM
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My carry ammo for my M&P9 is either Gold Dot 124gr+P or HST 124gr+P. Although the regular 124gr may very well be sufficient you never know what kind of situation you may end up in when you need to defend yourself. A muddy or bloody gun will cycle better with the extra power if the situation calls for it.
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Old 04-02-2022, 07:18 PM
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Quote:
Originally Posted by ddixie884 View Post
Yes, thanx for the link. Meanwhile I will say that I use some +P ammo and load some as well. I see no harm in having a 50rnd box of +P ammo to go with your HD firearm if it is one of the calibers available in +P...........
^^^what he said. Unless I read too quickly (I usually do, I'm brilliant, there was little or no mention/discusion of +P in .38 Spl., the round in which the concept arose. I would estimate that 99+% of the questions on this forum re +P use concern .38 revolvers.

At one time, +P in a LEO's 6-round .38 service revolver might be the difference between life and death. Perhaps not so much anymore, given improved ammunition in hi-cap semi-auto handguns. CC/SD users get to make their own decisions re ammo. You pays your money and you takes your chances. I'm simply not going to dismiss the extra power of +P as insignificant in a weapon of limited power to begin with. YMMV

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Old 09-19-2022, 08:43 PM
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Not mentioned was the fact that a JHP bullet needs velocity to expand, and some bullet designs in lower velocity (.38 Special, I'm looking at you) ammo often didn't have enough velocity. Even some early 9mm bullets were marginal at normal velocity. The extra ~100 fps of +P can make more difference than just some extra energy.
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Old 09-20-2022, 02:02 AM
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I believe that +P ammo is more beneficial in some calibers than others and not all +P ammo is an advantage - depending on the caliber, gun and actual firearm's barrel.

For instance, in many 2" Chief's Special revolvers the +P ammo usually makes expansion much more reliable. Since most won't like shooting +P out of their 2" Chief's anyway and cost has risen substantially, I doubt many would shoot enough of them to cause much of a wear issue.

As for pistols like the new Micro 9 class (Sig P365, SA Hellcat, etc.) that usually have around 3" barrels, I don't like +P ammo because it speeds up velocity enough to expand the bullet a little too fast and penetration suffers a bit. Expansion (of +P) is only marginally better and not substantial improvement over the standard velocity offerings (apples to apples) but the penetration is less than I would like - and penetration is actually better with the standard velocity version.

So I would suggest picking the choice of +P ammo wisely, depending on exactly what caliber, what barrel length and what firearm you are using it for. +P ammo is not necessarily better for all applications across the board. +P ammo usually slows down follow up shots as well - a consideration in picking SD ammo.

In some cases (as in many short barreled .38 spl's.) +P is the best way to go if you can shoot it proficiently. I would not however feed any J Frames a steady diet of +P's.

Last edited by chief38; 09-20-2022 at 02:06 AM.
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Old 09-26-2022, 07:44 PM
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Quote:
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. . . In some cases (as in many short barreled .38 spl's.) +P is the best way to go if you can shoot it proficiently. I would not however feed any J Frames a steady diet of +P's.
S&W explicitly rates some J-frame .38s as acceptable for +P.

Still, I would suggest that if you want to feed a J frame a steady diet of +P ammo, you purchase a .357 Mag J-frame. Designed to take .357 rounds with a Maximum Average Pressure of 35,000 PSI, a .357 should stand up quite well to regular use of .38 Special +Ps at 20,000 PSI.

(SAAMI standards also recognize .357 loads with a MAP of 45,000 CUP. Now, there's no accepted universal formula I know of for converting PSI to CUP, but pressure tested handloading data I've seen suggests that 45,000 CUP .357s may be "hotter" than 35,000 PSI .357s.)

If you're looking for what the standards actually are (including for proof loads) check out the data at saami.org.
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Old 09-29-2022, 08:17 PM
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IIRC the late Saxon Pig of this forum had a good take on +P ammo. He was very outspoken on it.

John
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Old 10-01-2022, 06:37 PM
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Quote:
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I don't think its such a great article.............

This is a terrible article, written in poor style, missing important key elements, and making dangerous assumptions about proof test loads and SAAMI limits and spreading this dangerous information publicly. It should be revised or removed.
Agree. The powder charge in a cartridge doesn't "explode" as a start. Then it goes even further down hill.

It's a pity that Speer took down an extremely detailed explanation of +P from their website. Or at least put it where I couldn't find it again. Especially before I could copy it for reference purposes.

After checking the SAAMI spec sheet for using the piezo-electric measuring system, .38 +P is a 9% pressure increase, 9 mm+P is a 10% pressure increase over standard velocity pressures. In the case of 9 mm, that gets the velocities up to about where CIP loaded ammunition is.
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