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Reader Randall writes:

While I’m not exactly a newbie when it comes to *using* firearms, I am a newbie gun *owner*.  And now that I’m in the position of purchasing ammo, I’m finding things to be rather confusing when sorting out all there is to be had. I have Nick’s “Getting Started with Firearms” Kindle book, but it doesn’t really address the topic. How ’bout an article for us newbie-types explaining what’s +P and +P+ and all those others?

Good question. This area of ammunition, the +P and +P+ stuff, can get a little confusing and a tad dangerous . . .

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When a gun goes off, the powder inside the cartridge burns and creates super-hot expanding gasses. Those gasses eventually push the bullet down the barrel, as that’s the path of least resistance for the gasses to escape. But since multiple manufacturers make ammunition marked with the same caliber designation, there needed to be a way to standardize the characteristics of each caliber so that gun makers and ammo makers could make products that work perfectly together and won’t blow up.

The good people at SAAMI (the Sporting Arms and Ammunition Manufacturers’ Institute) publish the official specifications for every cartridge. They dictate everything from the dimensions of the cartridge to the maximum pressure that the cartridge should produce. That keeps everyone on the same page when they make guns and ammo.

That second part, the maximum pressure bit, is extremely important. Gun makers use that number to figure out how thick the gun’s chamber and barrel should be to safely contain that pressure round after round. The guns are tested with a high pressure “proof load,” which is designed to produce a much, much higher pressure in the barrel than the listed maximum chamber pressure according to SAAMI.

The proof load replicates the “worst case scenario” and ensures that the gun can safely contain such a round and still operate, but guns are designed to function mainly on the lower standard pressure rounds. The gun will work using proof loads, but the parts will wear out extremely fast and the gun will quickly become unusable and unsafe.

While standard pressure ammunition is nice, some people (especially those using it in self defense firearms) believed that they needed more power. To illustrate the type of person who believes that .45 ACP isn’t enough and needs more oomph, I present an orangutan yelling “POWER!!!!”

So that’s the impetus behind the +P and +P+ stuff, people wanting to get more velocity or a heavier bullet in a traditional and standardized cartridge than the specs would allow without changing the dimensions. Unfortunately, the result of those changes is that the chamber pressure of the rounds exceed the maximum pressure specifications for normal, factory ammunition.

+P, pronounced “plus pee,” is a recognized “overpressure” load for ammunition that SAAMI officially blesses. The institute publishes the maximum allowable pressures for these loads as well as the standard cartridges, allowing firearms manufacturers to produce guns capable of safely handling round after round of the hot stuff without damaging the gun. +P loadings are offered for the standard self defense rounds of 9mm Luger, .45 ACP and .38 Special among others.

Since +P cartridges are typically only 10% above the normal pressure of a cartridge they will work in any properly maintained gun (the proof round is still a much higher pressure), but they will wear it out sooner and increase the chances that the gun will suffer a “structural failure.” Which is code for “blow up in your hand.” So the common advice is to not use +P as range / practice ammo.

.38 Super is the exception to the rule. The +P loading for .38 Auto, dubbed “.38 super,” is a standard competition load used in USPSA and 3-gun competitions. The ammunition is loaded much, MUCH hotter than the typical +10% and almost becomes its own caliber. This is the only +P loading that I would stay away from for novice shooters.

+P+ or “plus pee plus,” is a loading above the already over-loaded +P designation. This is for people who don’t think that +P is enough “stopping power” and want even more. But this is the point at which SAAMI draws the line. There are no standards for +P+ ammunition, it is simply “more” than +P.

Since the load is supposed to be still below the pressure of the proof cartridge, it should work fine once or twice in your gun. But prolonged usage will wear out your gun faster than +P. And the fact that there really is no official specification for +P+ means that there’s no way to really know what you’re getting. At that point, you’re putting your faith in your brand of ammo manufacturer to not overpressure the round too much, and your gun manufacturer to have designed the gun well.

Personally, I’m of the opinion that “stopping power” is a myth. The real thing you should be concerned about is shot placement, not how fast or how heavy your bullets are. So long as they can pierce someone’s chest they’re good enough. That’s why I carry normal factory ammunition in my gun. But for some people, their belief in the “stopping power” myth is strong enough that they need to risk permanent damage to their guns and the possibility of a “catastrophic failure” to squeeze those last few foot pounds out of their guns.

My advice: stay away from all the +P stuff.

[Email your firearms-related questions to “Ask Foghorn” via [email protected]. Click here to browse previous posts]

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125 COMMENTS

    • In the Diamondback manual that comes with the gun it says clearly, not rated for +P ammo. It says it all over their website and in everything written about the guns. The DB9 was built specifically to be very small, light, and THIN. The sacrifice you make is that there isn’t as much metal in the barrel of that brand of gun compared to other brands of 9mm.

      • No kidding. We’re talking about a 9mm handgun here which is thinner than most pocket .380s on the market (0.80″ at the slide).

  2. “While I’m not exactly a newbie when it comes to *using* firearms, I am a newbie gun *owner*”

    Made me think you might’ve been some kind of gang banger.

    I kid.

    • Or perhaps someone who just turned 18???? or 21 considering they are asking about handguns? Shessh we all started somewhere.

    • “Randall” here…no gangbanger, not [ex-]military either; and I wish I could claim something closer to the ages guessed… My story is, I grew up with grandparents who hunted, but my parents did not. So, while I shot guns at a young age, I didn’t really “grow up” with them. Many New Years celebrations included some shot guns in the revelry, but never fear: the homestead was out in the middle of nowhere, some 50+ acres, surrounded by even larger plots of undeveloped/under-used lands. My more recent experience is supervising my son’s Boy Scout troop’s “shooting sports weekends” and teaching him and my daughter firearms and shooting safety.

      As it turns out, I’m heading back to the ol’ homestead this week, and taking my pistol and rifle with me, and meeting up with my brothers to create an “arsenal o’ fun”!

      • “Underdeveloped” land is not “under-used” either, just maybe from a modern human perspective. It’s being used by other living things, and that’s a GOOD thing.

  4. I’ve witnessed two slide failures in 1911’s chambered for .38 super (and these were high dollar competition slides). I want no part of it, either.

    • .38 Super is a bit of an odd one, as the naming was to distinguish it from .38 ACP, which is actually the exact same cartridge size. There are to my knowledge no guns currently made for .38 ACP, which leaves the .38 Super as marked for +P, but at its own standard pressure.

      Failures in .38 Super guns may be from competition shooters trying to “make major,” to reach a specified power level for IPSC scoring. This leads some people to load ammunition well in excess of the SAAMI spec for the cartridge.

      Edit-guess I should have read through all the comments, same info covered lower down.

  5. I’ve got a few boxes of uzi black tip carbine 9mm. Feels like 38 super in my g-17. I love that stuff!

    • IMI 9mm ammo was distributed by Action Arms in their distinctive “UZI crate” packaging. It’s 115 grain FMJ and marked with a black tip, identifying it as high velocity. The box is marked “For use in carbines and submachine guns only. Not for use in pistols.”

      http://files.uzitalk.com/reference/pages/ammo.htm

      You might wish to rethink using that in a G17.

      • As a Glock armorer for close to 20 years, I’ve had many conversations with Glock reps. They all have said, shoot it.
        Ive got probably close to 100,000 rouds through my 17. Still shoots great. Carry ammo is +p gold dot.

        • 100K rounds?
          Through 1 gun?
          3600 seconds in an hour, roughly 300 hours of continuous shooting, sans reloads.
          Roughly a solid week of shooting non-stop through
          1 gun

        • Thats 5000 rounds a year.

          I believe him. In the next eight years, I should have a Glock 19 with that many through it also.

        • I had a Kimber with over 70000 through it when it was stolen. It still ran perfectly, and shot half dollar size groups at 25 yrds. Of course, when new, it shot quarter sized groups…

        • Dang, that’s a lot of rounds through a handgun. Glocks do take a beating. Buffalo Bore warns against +P in their .40 S & W factory standard barrels due to case support issues, whereas Underwood Ammo does not. The Underwood Ammo works great in my Glock 23, 27, and 35, and all of their stuff is +P and highly rated.

          Also, .45-70 has +P loads from Buffalo Bore and other manufacturers which works great.

          I wouldn’t make the blanket statement to avoid +P. Sure, parts wear out faster, but anything high performance does.

    • Oh yes. Got a couple of taped together boxes of surplus ammo at a gun show once. They were covered in lettering that I couldn’t make heads or tails out of. Guy at the booth told me they were 9mm sub gun ammo. He thought they were Egyptian but he wasn’t really sure of anything but they were 9mm. 25 rounds per box at 2 bucks a box. Bought all he had, 2 boxes.

      Took my Ruger P89 to an indoor range and proceeded to rock the world of the folks on both sides of me. That Ruger shot a Mosin Nagant M44 class of fireball out the muzzle and I swear it was rattling the stall with every shot. About half way thru my second California safe 10 round mag the RSO shut me down.

      Would I try that now? Not only no, but hell no!

    • Ensitue, who on earth takes nearly 11 seconds to shoot one round out of a glock, your calculations are seriously ballooned

  7. “The good people at SAAMI ….. dictate everything from the dimensions of the cartridge to the maximum pressure that the cartridge should produce.”

    Not exactly?

    SAAMI may report and/or publish such information, but don’t the individual ammunition manufacturers who actually do all the R&D and testing to design, engineer and produce each cartridge actually dictate the dimensions and charge for the cartridge they have created?

    • True, the original ammunition creator thinks up the design, case size, COAL, etc… but once the creator says “This is the way it should be.”, SAAMI puts it into their database and says “Anyone that makes this named caliber, these are the specifications to do it. Do it any other way and its not right.”

  8. Most modern guns can be used with +P and you only see +P with very old rounds such as 38 Special, 45 ACP, 9mm Luger, etc. A 40 S&W or 357 Sig is as hot as any +P+ 9mm. Correct me if I am wrong, but you can even run 45 Super in stock a Glock 21.

    • They make aftermarket barrels for that. I think they call it .460 Rowland make barrels for Glock, XD, and 1911. They made a MPA carbine for a short while too.

      • 45 Super and 460 Rowland have different case lengths. 45 Super is the same length as 45 ACP, but the 460 Rowland was designed a little longer, so that it would not fit in a standard 45 ACP chamber, for safety reasons. 460 Rowland is also a little more powerful than a 45 Super.

  9. I’d suggest that if you’re relying on +P+ in a personal defense weapon, it might be wise to re-consider your caliber choice.

  10. +P because some people think a .45 ACP 230 grain bullet at 850 FPS just is not good enough.

    • I’m with you on this one with the exception of short barreled .45s. I own a shortie 3.5-inch barreled one and the velocity drop on standard .45 ACP 230 grain is pretty dramatic, especially when you consider that the round is sub 900 fps to begin with. I use 185 grain +P ammo in that gun for SD.

      • i do not trust the gov’ment on many things but they got this one right 100 years ago and it seemed to work out through a couple of wars.

    • Some research instances indicate certain JHPs expand more consistently in +P loading when compared with their standard pressure equivalents during 4-layer denim testing. HST P45HST1 and Ranger RA45TP being two examples of such.

      An example to answer the question of “why +p?”. Your mileage may vary. The +P in those commercial loads translates to roughly ~50fps. So while it exceeds the spec, it does so only marginally.

      • Sure, I get that. .30 cal M1 Carbines were great against the Germans in urban warfare but on the frozen fields of Korea it sucked balls. But +P for that extra fps is like you said ‘marginal’.

    • Thats a over exaggeration.

      +P 45 ACP loads typically have 4-500 ft/lbs of energy.

      Perhaps you’re thinking of 45 Super?

      • Nope, no exaggeration. The US military deemed in testing ammo for the 1911 that 230 grain bullet at 850 fps was just fine for man killing (or testing on pigs). I think that is a fair standard to judge ammo by but if +P is what you need then maybe you need a bigger caliber.

        • Going to have to agree to disagree on this one. It’s difficult to paint in broad swaths when discussing different calibers, projectile composition, and charge weight. DPX significantly benefits from more powder, for example.

          Not arguing that 850fps of ball out of a 5″ 1911 platform couldn’t/doesn’t perform adequately. I will say that I believe it certainly isn’t ‘best in class’ or ideal for all situations. Also not a fan of military approval being the convincing point, but that’s me.

          Conversely: I don’t believe +P is all platforms is even close to ideal. In forty-five I shoot both. In many cases I am more accurate with the hotter rounds. It’s an individual per-platform/per-situation decision.

          I will heartily agree that just because it says “+P” doesn’t make it double-plus-good better. Like anything else… know your product.

  11. Nick,

    I don’t have ready access to my home library right now, but I believe that the reason that .38 Super was given the +P moniker was due to some confusion with using the cartridge in the old .38 ACP chambered pistols. The 2 cartridges (.38 ACP and .38 Super Auto) have identical external dimensions.

    I also disagree with your statement that the .39 Super +P is unsafe and should be avoided by novice shooters. My Series 70 Colt LW Commander in .38 Super has seen over 15,000 rounds of FACTORY +P rounds with no ill effects. This is a standard non-supported barrel pistol.

    The .38 Supers that were generally used in IPSC competition, ESPECIALLY, back-in-the-day of “realistic” major power factor loads (175 PF) were well above +P+ levels of pressure and really shouldn’t be used in an unsupported chamber. BITD – many of us were trying to reach obsurd levels of pressure to get the multi-chamber comps to work and were pushing 115-gr JHP to outrageous velocities (think 1500 fps plus) to make major. I have no idea what the pressures were, but you won’t find ANY loading data from the factories duplicating them!!!!!

    Oh to be young and stupid again!!!!!!!

  12. What +P means CAN vary by caliber.

    A classic example is the 45LC+P loads. These happened when a guy name of John Linebaugh realized that Ruger was producing 45LC guns that were just as strong as their 44Mag variants of the same gun – in other words, the cylinder was getting the same metallurgy, same heat-treat. This was different than S&W’s practice on their large-frame (“N” frame) wheelguns going way back.

    He therefore started loading (and publishing load data) for 45LC rounds that would blow up most 45LC guns, but would hold together in Ruger’s Blackhawks, Redhawks and SuperRedhawks. Pressure was bumped way, WAY past the 14k PSI range that SAAMI still calls for, and the 20k range that everybody knows a modern (post-WW2) Colt SAA or Italian replica can handle (and are not marked +P!) to the 33k range with bullet energies at or above 44Mag potential.

    Buffalo Bore and some other smaller ammo houses make 45LC+P to this kind of extreme standard and mark in BIG LETTERS what guns these can be shot in.

    Confusing the issue even more, Ruger later went and built a series of weaker 45LC guns based on the “mid-size frame” (New Vaquero and some limited-run Blackhawk Flattops post-2005) that are limited to post-WW2 Colt SAA pressure or perhaps a tad over but no way in hell 33k.

    Now. I have to take issue with the whole “avoid +P” thing because IF YOU KNOW WHAT YOU’RE DOING, and run +P ammo of known values in a gun known to be able to handle it, you can do just fine. I own a 9mm revolver that started life as a 357Magnum and has a massive beefy Bowen cylinder that I wouldn’t hesistate to feed +P, +P+, Czech subgun ammo, NATO spec or other weird 9mm variants in all day long. Same situation for a full-size Glock 9mm, esp. with one of the better aftermarket barrels on there, or any number of other very strong 9mm guns. Esp. ones that were built to 40S&W specs fairly recently and chambered in 9mm as an afterthought, such as the full-size FN polymer framed critters or many, many others (including the Gen4 Glocks). I might need a heavier recoil spring for the craziest stuff but I would not be concerned about a KB, more like long-term wear issues.

    Another type to be REALLY wary of is 38Special in +P+, esp. older stock. A lot of that stuff was marked “for police use only” and was basically…well, part of a giant fraud. Some of it was so close to 357Magnum spec it really should have been labeled that way. The point was for police to avoid having to admit they were shooting people with “Magnum ammo” once the “Dirty Harry” movies made “Magnum” an evil term in the mind of your average jury. I have heard horror stories about this stuff…but you can of course shoot it in a real 357Magnum gun all day long because that’s what it was really designed for.

    Be very careful about any +P load for which there’s no SAAMI standard – 45LC, 44Magnum, etc. Garrett Cartridges has been selling 44Mag+P as a bearstopper load and again, specifies VERY clearly that it is only safe in certain very large guns (mostly Ruger’s Redhawk and SuperRedhawk – NOT the SuperBlackhawk which has a smaller cylinder).

    Know what the hell you’re doing with this stuff. Be very careful. But I think “avoid completely” is overstated.

    • Don’t know the truth of this but some say the hot 38 Special “+P” loads of today fall within the standard pressure specifications for 38 Special back 50 or so years ago. Maybe the manufacturers got lawyered-up and invented “+P” to try to keep folks from using the hot loads in old guns i.e. those made before there was a “+P” designation.

      • No…well…sorta.

        🙂

        There were some fairly hot “standard” 38s out there, but a lot of the data was out of 8″ test barrels. Modern performance reports often use known real guns, like a 2″ barrel S&W model whatever.

        The big issue was that prior to the 357Mag there were the 38-44 loads. Now THOSE were hot. They were made for “44 sized guns” (meaning 44Spl). These loads existed because of the S&W N-frame 38Spl guns like the Outdoorsman. That was the first “+P” load and it was easily +P or even +P+ by modern standards. Too many idiots put these in lesser guns and that was a key reason for the creation of the longer 357 cartridge.

        Many of those N-frame 38s were successfully re-chambered to 357…I’ve seen credible reports that one of these did bear-stopping duty in Alaska for many years in the hands of a bush pilot and actually killed a bear in self defense. That one actually started as a 1917 45ACP and got a 38Spl-length cylinder and 357-marked barrel installed at some point so…clearly the concept was valid!

        • We need to start a reference list of Elmer’s books for these youngsters to start reading.

          If people knew how many wheelguns Elmer and his posse’ abused (and sometimes destroyed) testing their high pressure loads, they’d have a safety cow today. In Elmer’s day, hey, it was just part of the experimentation.

          And yes, that .38-44 was one hot, hot round. I seem to recall Keith loading it with 12 to 13 gr of 2400 powder. That’s the same load he’d put into a .357 when it came out. The .38-44 was the precursor of the .357.

    • The central problem is that there’s now a lot of people who aren’t willing to study and understand the differences in actions and construction of firearms that enables some to take really hot loads vs. others that won’t. Too many people just don’t want to learn the level of details and trivia necessary to exhibit prudent judgement in reloading and cartridge development.

      An example of the contra-indication of allowing people to think for themselves on loads would be this: I’ve had people insist that a Trapdoor Springfield could take the same load as a Ruger #1 because (you’re going to love this reasoning) “… they’re both single-shot rifles.”

      Siiiigh. As some youngsters would say: “Insert epic face-palm here.”

      We both know that’s not going to work out well for them. I’ve tried to explain the differences. What do I know? I’m just a gunsmith who has never written anything in a glossy gun rag, so I’m a drooling idiot…

      In light of that, prudent people who find lawyers to be a proctological nuisance fall back on assuming that everyone is a moron (including said lawyers), and start spouting one-size-fits-all, regardless of the audience IQ or ability. If I treat everyone as a self-destructive moron, I can’t be sued for insulting the intellect of higher IQ people. At least not yet, anyway.

      Linebaugh has pushed modern revolvers to performance levels never expected by their own designers – because John understands exactly what is going on in a revolver and is willing to learn and understand all the deep details.

      • DG – Referencing my earlier post………..

        I even tried some 100 grn .380 FMJ at major. SERIOUS overpressure at 1600 fps with AA#7, and didn’t get better with VihtaVouri (3N37 – I think – would have to look back). Finally split a BARSTO fully supported barrel through the hood and felt that 115s were the limit of “light”!

        But as you said, we took chances but understood the limitations that we were faced with.

        BTW – Full agreement on the proctological nuisance of of lawyers!

      • Only vaguely related: always enjoy reading your posts DG. If you don’t partake already, I respectfully suggest a blog.

        Especially fond of your antique/obscure firearm knowledge. Too much whiz-bang plastic shiny around these days… need more good ‘ol fashioned wood and engraving.

        /thread hijack

    • I will agree to agree with Glock. I have a Gen 4 Glock 19. I run standard ammo for practice, and +P for EDC. Say what you want, but I’m more accurate with a 9mm than a larger caliber weapon. Also, more accurate with +P rounds. I want the additional penetration afforded by the +P rounds, and Glock says the G19 will handle the added pressure with no problems. As I stated above, practice is done with standard ammo. The +P is just for the the potential of needing to defend myself, or my family.

    • I have a 357 magnum, but I load with 38 +p for self defense. I don’t want to go permanently deaf, and I shoot 38 +p damn accurate out of a heavy revolver. Can’t be as tiresome on the gun as magnums.

  13. The one item that I did not see on the previous comments involves the trial after a self-defense shooting. I only carry factory standard ammunition in my XDm. Never hand loads and never +P. The prosecutor will have a field day with you if you shoot someone with that sort of ammo. “Mr Smith can you explain to the jury just why you felt is was necessary to use such massive killing power in your weapon?”

    • I carry Winchester Ranger 127gr +p+ 9mm in my Glock 19.

      “I’m using what the cops use” should be good enough.

      • Viscerally, I’d like to agree with you but most of the literature that I’ve read, and my formal training at Frontsight reinforces my post.

        • Odd, my formal training at Front Sight said find out what ammo your local PDs are using and use that.

        • Mike, unless Mr. Smith chooses to take the stand (a massive mistake most of the time), the prosecutor isn’t going to be able to ask him anything. 5th Amendment and all that.

          Will a corrupt prosecutor (pardon my redundancy) try to exploit the use of any particular ammo to discredit a self-defense shooter? The answer is “yes, of course.” The only way to avoid such underhanded tactics is for a man to shoot .22 shorts.

      • Which department is this? Mine uses standard pressure Winchester Ranger for 9mm, .40, and .45

        Not criticizing, just curious. I don’t have information for all the different local agencies, but I’m not aware of one in the general Seattle area that issues +P as standard.

    • “If I’d wanted massive killing power, I’d have brought a .308 rifle, not a handgun.”

    • Really?

      My revolver started life as a 357Magnum, peak muzzle energy up near 800ft/lbs.

      It is now a 9mm. It can easily shoot the wildest 9mm+P+ out there, which top out at around 500ft/lbs.

      So let’s say I use those. 500 versus what I used to shoot, 800. I’m completely bat%$# crazy? Really?

      Take another good example: in 1986 there was a failure to stop in a serious confrontation the FBI had with two murderous lunatics. The failure was blamed on a standard pressure 9mm early in the fight that might otherwise have stopped the bad guy who went on to do most of the killing. That led the FBI to try out the 10mm before settling on the 40S&W which lays down between 500 and 550ft/lb of energy – maybe 600 with the very best loads.

      That has also now become the dominant standard in police circles.

      BUT, we now have 9mm loads that come borderline close to the 40 – between 450 and 500ft/lbs of energy. Now that’s just a tad under what modern law enforcement normally considers workable.

      Again: how does using that class of load make me a nutcase?

      These attempts by prosecutors to turn on people over gun and/or ammo choices can in fact backfire on ’em. Attempts of this sort can be turned around and used to show that the SOBs are desperate – BECAUSE THEY DON’T OTHERWISE HAVE A CASE.

      • Remember, in a civil wrongful death suit, they don’t need to overcome “reasonable doubt.” All they need is a standard of “preponderance of evidence,” and they’ll throw in everything and the kitchen sink, because they’re trying to meet the standard of “preponderance” of “evidence” that you intended to shoot someone “to kill” and so forth.

        In a criminal trial, +P or handloads shouldn’t make a difference. If you had reasonable fear which allowed you to shoot a .22, you could shoot them with a Four Bore and still be on firm legal ground.

        • Some lawyers used to try to pose this as being “intent to kill” when cops used to carry FMJ, but now most LEO’s carry HP’s as well, so it’s not the issue it was when I was younger.

      • The FBI Miami shootout and North Hollywood shootout were definitely hard lessons learned.

        The infuriating part about the conclusions from the AARs is that they both should have started discussions about what long guns for field agents to use during arrests or for police officers to carry in their cruisers.

        In either case, the relatively common CAR15 or XM177 (Colt Commando) would have been a defining game changer for both scenarios. Easy to obtain, with a bunch of different loads that can be more ideal for urban warfare.

        Instead the FBI sought the “overpowered to use effectively” 10mm and the 40 which basically performs very similar to 9mm and 45. Talk about reinventing the wheel.

        Then police agencies started flocking to 45 and 40 as if they would have penetrated the kevlar body armor of the North Hollywood shooters better. /rolls eyes/. Fortunately, police agencies caught on and started issuing AR15s or surplus M16s.

  14. Every pistol, even of the same or similar make, is just a little different.
    For instance, I have a stock Browning Hi-Power that loves +P loads.
    I reload 147gr rounds near +P (1170fps) and the pistol functions
    flawlessly. If I put in standard 124gr loads, the recoil feels sharper.
    I have an XD that reacts similarly. Though it doesn’t really like +P
    loads, it does like 124gr loaded slighly faster at 1130fps.
    Conversely, I had a 686 that hated .357mag. If I loaded down or
    put in .38 special it was a tack driver.

    In short the ammo used (especially defensive rds) should be
    tailored to the gun and you.

  15. Oddly enough my Sigma shoots most accurately with +P level loads. It’s not a precision target weapon but it’s tightest groups are with +P loads. I only shot a couple of boxes of the +P thru it when it was new and I was testing different types of ammo in it. For economies sake I save the +P stuff for self defense loads. Same with my .38s. I have a few boxes of the old Chicago/FBI load that I cling too for SHTF situations.

  16. Great article! Quick follow-up question. Say you have a .357 magnum revolver, which necessarily will also fire .38 special. Is it a reasonable assumption that .38 +P can be used with safety in such a wheel gun?

    • I looked up the SAAMI specs and found these numbers:
      38 Special… 17,000 psi max
      38 Special +p… 20,000 psi max
      357 Magnum… 35,000 psi max

      So the 38 Special +P is a mere snack for a 357 Mag.

    • It’s a reasonable assumption that .38 +P can be used with safety
      in a MODERN wheel gun. But there are caveats. If you put
      .38+Ps in a 357 cylinder you may get more fowling and build
      up around the cylinder head. That’s been my experience anyway.
      Also, my definition of modern is within 50years. In older
      firearms you can run into two main issues: 1) the metallurgy
      wasn’t as advanced son there’s an increase chance of structural
      failure and 2) you have to address the advancements in powders.
      These two issues are why you generally see warnings to never
      use current ammo in old pistols, especially those made before
      1900. The .357 wasn’t made until the 1950’s so you’re probably
      fine. But if you had an older revolver, say a .38 from 1920 or
      a Peacemaker from the 1880s, and were looking at using +P or
      even reloading you’d need to do a lot of research.

  18. I’ve spent the last year evaluating the costs/benefits of +P and +P+ 9mm ammunition and have come to the conclusion that you really do not need it.

    you are given increased muzzle flash, increased slide cycle speed which equals more wear and tear, more recoil which means inferior controllability, all for a extra 50-100 ft/lbs. You’re essentially “40-izing” the 9mm.

    To me it is not worth it. I just use the Winchester ranger 147 gr bonded JHP and stick to anything 124 grains and above for defense.

    • I read an article once that said that some police forces had dropped from 147 gr to 124 for two reasons: less over penetration, and faster follow up shots with greater accuracy. What the lighter bullet loses in mass it makes up for in velocity (for standard loadings).

      • from a evidence standpoint, lighter bullets are more adversely affected by clothing, bone, etc; things that basically cause a lack of penetration. That is why I dont agree with anything lighter than 124 grain, although this is what corbon seems to do.

        From my experience the heavier grained 9mm shoots slower with more of a push kind of like a 45 ACP versus a quicker snap.

        Its purely subjective. My viewpoint is merely a opinion and, more specifically, is non scientific at best.

      • Odd. I know recoil is subjective, but I always thought the heavy bullet subsonic 9mm loads, like the typical 147s, had softer recoil and less muzzle rise than the 115s or 124s, especially if the latter were +P or +P+. Lots of competitors seem to feel the same–people who shoot steel plates for prize money seem to favor handloads with heavy bullets and modest charges of slower-burning powders, and it makes a difference they say they can measure in their split times.

        In the .40, likewise the heavy bullet 180gr loads are soft shooting for me, but the 165s and 155s feel snappy, with more muzzle rise. But in the .45, it’s 185gr and 200gr bullets that feel soft-shooting for me and the heavy 230gr ones that seem to have more recoil.

  19. One thing to bear in mind is that +P loads can be safe in some guns without any notable shortening of life. E.g., if you have a 357 magnum, you may load 38 +P as a compromise round. Still going to be fine. And some guns are designed specifically as safe with +P 9mm.

    My understanding as well is that with 38 spl guns +P and +P+ were both developed for police use, after numerous complaints about 38 spl sucking at stopping bad guys. 38 +P was the FBI load for a while, and police guns after 1972 were generally designed with it in mind.

    • It’s true. There are American Rifleman articles from 1946-47 in which they talk about how American commercial 9mm ammo is weak stuff compared to the German milspec ammo, and guys who brought home a war trophy Luger in their duffle bags constantly complained about how American commercial ammo wouldn’t cycle them. There were articles about how many coils to clip off the recoil springs so that they’d run on the ammo non-handloaders had available to them.

      And yes, German wartime 9x19mm ammo was some pretty ferocious stuff. Specs varied but the Lugers were set up to run with a 124gr (eight gram) FMJ roundnose bullet cooking along at 1200+ ft/sec from the 4″ barrel versions, which ran around 40,000-42,000 PSI. There was a wartime substitute standard loading using a 90gr roundnose bullet in a lacquered steel cartridge case, that had a sintered soft iron core, loaded to 1400-1500 ft/sec, faster from SMGs. American commercial ammo at the time was usually a 115gr FMJ roundnose at 1050-1100 ft/sec and loaded to maybe 25,000-28,000 PSI, so as not to blow up Grandpa’s war trophy Italian Glisenti.

  20. In the olden days we were issued .38+p for our .357 revolvers. After a few years of lobbying the powers that be we got 357 ammo. So +p was a work around to give folks a little more power in the face of political considerations.

    9mm sub ammo was famous for being high pressure and not for handgun use, although Ruger famously plugged a barrel of a P85 and fired a round, replaced the extractor and continued on. I wouldnt worry about +p+ in that weapon, although i wouldnt use it in a p38 and def not in a p08

    Am much more worried about unlabeled or hand loaded ammo then properly labeled +p+ used sparingly in a modern weapon in good condition.

  21. Since +P cartridges are typically only 10% above the normal pressure of a cartridge they will work in any properly maintained gun (the proof round is still a much higher pressure),…

    Exactly..

    but they will wear it out sooner and increase the chances that the gun will suffer a “structural failure.”

    What?! No!! All modern guns can handle a steady diet of +P ammo. There is no appreciable increase of wear–it’s only a 10% increase in pressure after all and still equivalent to the pressures of most modern cartridges.

    Which is code for “blow up in your hand.” So the common advice is to not use +P as range / practice ammo.

    This is simply misleading and you miss an opportunity to state the major MAJOR point that +P should never be used in “older” guns. If a person thinks that their gun dates to a time if inferior metallurgy, than assume that it does and keep to standard pressure loads.

    As far as whether or not +P is useful, I think that it certainly does have a place especially in the case of shorter barrels. Remember, “+P” is simply trying to bring older cartridges into the “normal” pressure range of more modern loads.

    • There are exceptions. I noted that the 45LC+P loads jump you to as much as 33k PSI. Standard is…well, it’s either 14k (SAAMI) or 20k (as everybody knows you can use that in almost all modern 45LC guns except for the open-top conversions and some break-opens such as the Schofield replicas).

      Anyways. 33k is way more than 10% over 20k, let alone 14.

  22. +P, +P+, and pistol caliber hollow points = more money out of your wallet for little or no gain.

    Shoot your target more than once, and save money in the end.

  23. I can’t afford Zombie ammo, so I painted the tips of my available ammo flourescent green. I don’t know if this will cause any additional wear and tear on my gun even though it is not specifically marked as +Z on the barrel.

  24. Foghorn. Whoever you are, you are amazing. I am an older guy who has been shooting for many years but never knew much about the technical stuff. I have learned more this year since starting to read your blogs and I really appreciate your work technically and general philosophy. Thanks

    • Its pretty difficult to go wrong with the Ranger-T series. Contrary to popular belief, the ‘T’ series is not the Black Talons of yesteryear. It is actually a more advanced/better performing design.

      I personally would not have opted for the +P+ as 42000 CUP is significant and I don’t feel the extra flash provides any corresponding benefit. A well-built solid platform should handle it, but you’ll want to research for yourself.

      My de facto stance is ‘heavier is better’. When given a choice, I prefer 147gr in 9, 180gr in 40 (when I still had 40 pistols), and 230gr in 45. The exception is DPX, where 45/185gr is brilliant… no heavier available as its the equivalent of 230 in jacketed lead.

      • You are correct, though we should also note that Winchester has three different duty loads available for those who like the Ranger-T bullet.

        A standard pressure 147gr bullet loaded to about 950 ft/sec.

        A 124gr bullet loaded to 1200 ft/sec and rated at +P pressures.

        A 127gr bullet loaded to 1250 ft/sec and rated at +P+ pressures.

        All three are in widespread police service in the US and the last one, the 127, is the most popular of the three. But all seem to be very good performers, if you can get them. I am writing this during the runup to the 2020 elections in the US. If anyone reads this in the future, we are having a bit of a gun and ammo panic right now. A lot more people want guns and ammo just now than did a year ago, it seems, and there’s not enough to go around.

        You are lucky right now to find Russian steel case 9mm ammo available for sale, and that at five times the price of a year ago, much less your favorite hollowpoints. And, you know, over the course of the 20th Century, a whole lot of people were killed with 9mm FMJ bullets. It’s not best in class, it’s not ideal for every application, but it beats the heck out of harsh language.

    • Personally, I stick with “regular” winchester ranger loadings and stay away from +P and +P+.

      I used to be a strong believer in obtaining every advantage i could obtain in my handgun, although I was really wrapped around the axle in squeezing out that extra 100 ft/lbs of energy.

      Throughout last year, I found out that overpressure cartridges increase muzzle flash, slide cycling, and recoil (which affects controllability) for just a extra hundred ft/pounds or so of kinetic energy that *might (or not in most instances) improve penetration and expansion.

      To me, the advantages did not outweigh the disadvantages so i stopped carrying them in my self defense handgun.

      Im not going to say you made a mistake or that you were ripped off: they are excellent self defense cartridges. Youll just “40-ize” your 9mm. 😉

      • I would stay away from +p in the lightweight platforms like the ‘Skittle popper’ pf9 and the like. There are some pretty good loads that give you optimum penetration and good expansion without having to deal with the effects of brutal recoil. I agree with you that, if your just shooting +p out of your regular nine, might as well go .40 cuz the gun is beefed up for it a little bit (like the G22 vs G17) and you can pop in a conversion barrel and plink with 9mm.

    • Keep them ! I carry 31 of those babies when I walk out my door in my Glock 19. For me the Winchester 127 +P+ is the straightest shooting ammo for that gun, also a funny thing about that ammo is its value has gone up since I got a small stock of them, when I got them it cost me a few cents under $30 per 50 rounds now I see 2 boxes of them (100 rounds) go for $100 sometimes more !

  26. Simple safety rule: only use the ammo designed for your weapon. If your weapon lists ‘+P’, then you can use regular or ‘+P’. If not, then only use regular ammo. Not that hard of a rule…

    One point, I thought ‘+P’ was about 20% more pressure and ‘+P+’ was about 40% more pressure.

    Could it be that ‘+P’ started out out higher and has come back down to 10% more pressure?

  27. Is it true that there is +P+ 9x19mm out there that was designed specifically for sub-machine guns? That’s what I always thought it was, either some wild hand loaded shit like Buffalo Bore or subgun ammo. I don’t think I’ve ever seen +P+ in anything other than 9×19 and even that was just online.

    • Most European military 9mm ammo, at least during the Cold War, was loaded much hotter than American commercial 9mm ammo. Sometimes people selling military surplus 9mm ammunition in the US will describe it as “submachinegun ammo” but it certainly saw a lot of use in handguns also–breaking some of them (British “2Z” spec 9mm SMG ammo, originally intended for use in Sten and Sterling open-bolt SMGs, was screaming hot stuff, infamous for cracking frames and slides on Browning Hi-Powers–and Austrian “Hirtenberger” 9mm SMG ammo was hotter still, Israeli “black tip” SMG ammo is also extremely hot, as is Swedish Sak Ptr M39/b 9mm SMG ammo, as was Czech export ammo). And yes, most of it was loaded to significantly higher pressures–sometimes reaching the 40,000-42,000 PSI range–than American commercial 9mm ammo, which is on paper limited to 35,000 PSI and as a general rule loaded to under 30,000.

  28. Small nit about “proof loads” and “proofing:”

    In the US, we have no formal “proofing” process as they have in the UK or Europe. In the UK, there are very stringent specifications of proofing, proofing requirements (provisional and final) on barrels and chambers, requirements for when guns need to be re-proofed after modifications, etc.

    In the US, we lack all of that. So we just fire “hot” loads through the gun.

    But (and here’s the nit): These testing loads are NOT the “worst case.” Far from it.

    A worst case load (as an example) would be filling a .45 Colt case with a very fast burning pistol powder – say, oh, Bullseye. I don’t know of any modern firearm that would withstand a case full of this powder with a 300gr pill on top. The pressures would be through the roof – and that would be a “worst case” combination.

    Take another, even worse, “worse case:” Take a .45-70 case. Fill it with Red Dot (or similar) powder. Put a 535gr pill on it. Shove it into a Trapdoor. Fire. Right there is perhaps the ultimate “worst case.”

    In England, at the Birmingham Proof House, they favor increasing pressures by loading heavier projectiles or shot loads on top of standard powder loads for lighter bullets. They’re looking for changing dimensions on the barrels, or bulges, as well as case failure. If they see none with their standard proof loads, the proof marks are struck onto the barrels and the gun is done. The pressures aren’t “worst case” – but they’re significantly elevated over the common “maximum average pressure” CIP spec for the cartridges involved. In the UK, since 1813, it has been an offense to sell any firearm that has failed to obtain a proofing from a proof house upon new manufacture or modification that requires re-proofing by law.

    In the US, we have no requirement of firearms proofing or testing before a gun is sold. Without proofing standards, we have SAAMI recommendations but guns that are heavily over-built because they’re only recommendations. There’s no proof house to test a gun (or a load) before it goes out to the public. The closest thing we have to a proof house is the private lab, H.P. White:

    http://www.hpwhite.com/

    • Ruger proofs their firearms in-house with ammunition loaded to at least 50% over SAAMI max pressure specs. This means that, for example, each Redhawk in .454 Casull, for which SAAMI max pressure is 60,000 PSI, is tested with proof load ammo developing at least 90,000 PSI pressure, on each chamber in the cylinder.

      And yes, this requires the Redhawks in .454 to have cylinders made of a special grade of stainless steel and subjected to a special heat treatment, making them much stronger than the Redhawks in other calibers.

  30. I shoot +p all the time in my rugers and glocks, absolutely no issues with failures, excessive wear or any other other issues. +p is only a tad(5–15%) pressures above SAAMI. You can shoot +p all day and night in quality firearms that are taken care of. I have access to tons of +p 9mm and I shoot 2-3 times a week hundreds of rounds per handgun per day all year long and I have noticed no ill effects of any kind from +p ammo. At least in 9mm. My target ammo is most people’s defensive ammo so my guns rarely see underpowered target fmj.

    Don’t be afraid of a little pressure.

  31. Important thing to note:

    There are only a handful of cartridges that have a +P version designated by SAAMI. Any other cartridge that is marked +P by the manufacturer is by definition an overloaded cartridge.

    These cartridges are:
    .45 ACP — 23,000 psi vs 21,000
    9mm Luger — 38,500 psi vs 35,000
    .38 S&W Special — 20,000 psi vs 17,000 (note the standard pressure was LOWERED in 1972)
    .38 Auto (aka .38 Super) 36,500 vs 26,500 psi
    .257 Roberts 58,000 psi vs 54,000

    Any other cartridge marked +P is an intentional overload, and/or marketing gimick. Unless the manufacturer published actual test data the pressure could be almost anything.

  32. Why not just use a .40? Fifteen instead of seventeen rounds on tap is a small loss in ammo for getting the other advantages the cartridge gives.

  33. I have a question. So I purchased a sig P250. Absolutely love this gun. My question is: the manual clearly states not to use +P rounds and I intend do not use them. However, I did buy a box of Fiocchi XTP 145 grin rounds for it. The box does not state if the round is a +p, After doing some a little research on other forums, some folks stated it might as well be a +p round. With that said. Is it safe too use it as a defense round and not have this gun blow up in my hand after the first 5 rounds? if I hand too use it as such?

  34. With all due respect, Randall’s original question makes me wonder how people can buy handguns without being required to take a firearms training and safety course from a certified NRA instructor.

    • @spidero:

      With all due respect, it’s called the Second Amendment.

      You should read it. Short, sweet, to the point, and worth your time.

      I find myself reading it again and again….. 🙂

      • I don’t have a problem with the Second Amendment. Basic gun safety training, including proper ammo usage, just makes sense – preferably before you buy a gun!

        • You specifically asked, “makes me wonder how people can buy handguns without being required to take a firearms training and safety course”, and I specifically answered that question.

          DO NOT PRETEND to support the 2A (as written) when you clearly DO NOT.

          • RKBA: The best way to preserve 2A is to read the NRA Guide to the Basics of Pistol Shooting, Chapter 1, Basic Firearm Safety.

            • Spidero,

              While I am an avid proponent if safe firearm use and continued education, I find your suggestion that simply reading NRA literature somehow preserves the 2A.

              The only tried and true method of preserving the 2A is to refresh the tree of liberty with the blood of tyrants and patriots.

              • RKBA,

                My point was and is:

                1. Safe firearm use helps preserve 2A.
                2. Unsafe firearm use jeopardizes 2A.

                Aloha!

    • With all due respect, I wonder what makes you think I didn’t have any firearms training before I bought my firearms? I’ve actually been through two safety training classes, in addition to the required CHP class, not to mention supervising several Boy Scout shooting sports weekends, not to mention copious amounts of reading and research on firearms, training, and the Second Amendment and the plethora of federal and state laws under to which I am bound.

      With all due respect, I went well above and beyond any “requirement”, the only one really being a human being, and one lucky enough to live in this great country whose founders realized the necessity of protecting a natural right in our Constitution (it’s in my state Constitution, as well).

      That doesn’t mean that I’m an expert on the nuances amongst the various ammo types. So I asked here, as a furtherance of my education.

      Spidero, wi\th all due respect, how about keeping your ill-conceived, naive judgements to yourself until you know the whole story. (The lack of a question mark there was on purpose.)

      • Randall: My comment was not meant to be personal. I’m glad you asked your question and Foghorn did a great job of explaining it. I didn’t know what all the cartridge nomenclature meant either before I took the NRA Pistol Safety class that is required before you can obtain a handgun permit in my state. Aloha!

  36. After 1,650 rounds of Underwood 230 grain +p through my Kimber tle II and 2,220 rounds of Underwood 124 grain GD +p+ through my M&P 9mm CORE 5″ there is zero visible wear, performance or accuracy loss compared to the exact and similar handguns shot with standard loads near same round count. MOST handgun brands like S&W, Glock and HK test their best sellers with repeated over max rounds and there has only been a couple catastrophic failures after many thousands of rounds in hundreds of different handguns. All failures were in handguns with pencil type barrels meant for light loads.
    Handloaders test the limits all the time with no issues. The only handguns I’d be careful with using +p or +p+ loads is pocket pistols. Any full-size semi can handle many thousands of rounds of +p+ shooting. The extra wear and tear is myth and truth, yes parts more so the barrel or any part taking the direct abuse of the extra power will wear out quicker but not ridiculously quicker.

    “it should work fine once or twice in your gun. But prolonged usage will wear out your gun faster than +P” Not true. Please don’t state something as fact when it’s myth.+p and +p+ wear out parts at the same rate, the only great differences in wear would be on brass. The difference between standard and +p/+p+ is 10% less life. Hardly an issue for most folks especially when most are replacing barrels in their semi’s on a regular basis. Revolvers? Forget about it! I’ve loaded such hot loads in my S&W revolvers from .38 to .500 and I’ve never had a failure or issue.

    “I’m of the opinion that “stopping power” is a myth.” This verifies you don’t know much about ballistics.

    • http://tech.firstpost.com/watch-videos/9mm-vs-45-vs-rifle-a-drs-view-of-gunshot-wounds-graphic-photos-_tku8YI68-JA.htm
      lars i suggest you watch this vid and allso read the comments from doctors ,paramedics etc about handgun balaistics and stopping power.you might learn something.handgun stopping power is bs pretty much.balistics only really matter when you get to rifle balistics.the few more fps you get from +p etc doesen’t really do anything significant.it is bs

    • Visible being the key word, keep shooting that Underwood garbage and you’ll break your gun. As a handloader I would stop way before what Underwood loads his ammo to as would 99 percent of reloaders, but since it comes in a shiny package from a company the uninformed or naive think it’s safe. Underwood doesn’t even have pressure testing equipment, they use standard components available to anyone, they just load way beyond what any loading books would ever recommend.

  37. I use +p in my carbine and get an extra 300fps easy in performance. Since my pistol is also chambered 9mm, occasionally they wind up running through that as well. NEVER a problem. Cannot speak to +p+.

    Stopping and killing power are subjective views until one places a round within the 12×18 inch biomass we refer to as the torso, and then even the lowly .22 can claim success.

  39. I Appreciate You Writing this Information.I am going to heed your Advice and stay away from any of the +P Ammo I have a Browning Hi-Power that I like a lot and do not want to mess it up.

  40. Might there be an advantage using +P or +P+ for pistol caliber carbines and the distance?
    All the ballistic gelatin test I’ve seen are for pistols and 10 foot range.

  41. I lived next door to a guy for years who was a high ranking civilian working in the DOD for a branch of the military. He was in charge of ordering equipment for a base in the south notorious for training and supplying SF. Not giving details because I liked the guy a lot… had some great stories but the day he told me about the +p+ for assassins and a CO or a 2* (cant remember what he said bc of how fast he talked) halting the ordering of shotguns for breaching doorways in afghanistan because he’d rather breach with a HP round from a abraham’s I knew he had some good shit to talk about.

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