9mm ZQI Ammunition Out Of Battery Firing (kB)!

An unfortunate poster over at AR15.com had a dramatic out of battery firing with his 9mm AR pistol this week. While it’s not clear that the ammunition is to blame, it certainly is a possibility. Regardless, this is probably the worst out-of-battery firing I have seen in a while:

Took the newest build out today for some fun. I had 100 rounds of fiocchi down the pipe already, and put another 100 right on everything I was pointing at.

Then I swithced to the ZQ stuff I bought a few months back when walmart had it on sale.
first round.

The culprit.

After cleaning out the brass dust, it seems like the gun is ok.

It started as such a good trip..


For whatever reason, I’ve found that out-of-battery firings with pistol-caliber carbines (which – technically speaking – this was not) are not that uncommon. I’ve seen a good number of them happen in person – in one case as a repeatable malfunction that happened to a weapon I owned (naturally, it quickly got sent back to the manufacturer). However, I’ve never seen an out-of-battery firing with a rifle-caliber carbine (though that doesn’t mean they don’t happen!).

Fortunately, in this case, nobody was hurt, and the gun survived, too.
Stay safe, folks.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


  • Tim Pearce

    Personal Experience: Timney triggers do not like the recoil impulse of a blowback upper. I had my disconnector’s set screw loosen up fast when using blowback uppers — which every pistol cartridge AR-15 upper I’ve seen is, though I’ve heard there are individual gunsmiths that make gas-operated PCC uppers. I quickly packed up and headed home when it happened, each time, but one time the 10mm case that it had fired was swollen out on all sides. It had fired out of battery, and the case had *just barely* held the pressure. I eventually got rid of those uppers.

  • echelon

    This is why I find myself gravitating only towards designs that were designed around a specific cartridge

    • SM

      Are you suggesting that things work best when used the way they were originally intended?

    • sianmink

      That’s why I only use Colt 1911’s chambered in .38 ACP.

      • echelon


    • Christian Hedegaard-Schou

      Please help me understand why another “9mm-specific” blowback design would be any safer than a 9mm AR?

      • echelon

        Because other “bastardized” or “frankengun” solutions sometimes have design shortcomings that are sometimes hard to spot at first glance or they are easy to dismiss or overlook.

        In all of these new switch barrel, multi cal designs the tests are basically coming back and the data is telling us that these “one gun to rule them all” designs that can be whatever we want them to be are coming up short.

        In short the AR platform was not designed with the 9mm cartridge in mind. So sure, some engineer or designer might be able to just slam a blowback action and all the necessary components into an AR design, but that doesn’t mean it’s going to really be any good or hold up better than a design that was built from the get go as a 9mm blowback design.

        It’s all about priorities and design tradeoffs that must be made.

        • Christian Hedegaard-Schou

          You didn’t answer the question.

          • echelon

            I did. You just apparently don’t like or accept my answer.

  • DIBs

    Once upon a time i had a PPSH blow up on me out of battery and turn my left arm and parts of my face into a smoking bloody mess. F?$k that gun forever. Thank God I was wearing eye pro. It took some time for my medic to pull all the pieces of brass and steel with forceps. Plus the powder was literally still burning in my skin for a few seconds. No more Russki PCCs for this guy.

  • justin

    an ar-15 in 9mm bolt mechanically can NOT fire out of battery, that kb is due to excessive energy from the propellent gases/bullet acting against an unlocked bolt. this rearward movement of the bolt and buffer are quiet slow compared to relatively low mass of the bullet and gas. the formula for this is moment of inertia (Mass1 x Velocity1 = Mass2 x Velocity2). if the cartridge’s momentum is very high then the bolt/buffer receiving the equal and opposite force (newtons laws) will also have high momentum. what that means is that the bolt must move faster because bolt/buffer’s mass is not changed. there is a point where the mass of the bolt and buffer as well as the weight of the spring limit how much energy you can fire. a cartridge that is too powerful will extracted/push out of the chamber while the pressure still too high for the brass to withstand. if this is not hot ammo then its most likely overcharged with powder. also you can add mass to the buffer and/or add weight to the action spring to fire +P or +P+ more reliably.

    • anon

      “an ar-15 in 9mm bolt mechanically can NOT fire out of battery”


      • justin

        sorry typo, “an ar-15, in 9mm, mechanically cannot fire out of battery”. as in the hammer cannot strike the firing pin if the bolt is not fully seated in the forward position. the bolt has a ledge below the firing pin that blocks the hammer

        • Paladin

          Just because the hammer can’t strike the firing pin doesn’t mean that the bolt is mechanically incapable of causing an OOB detonation. If the firing pin channel is sufficiently fouled it may hold the firing pin forward, as happens with some frequency with the SKS.

          In a gas-operated AR15 on the other hand (unlike the straight blowback 9mm) the bolt/BCG expands and collapses as the bolt moves in and out of battery, which renders it mechanically impossible for the firing pin to contact the primer until the bolt is fully in battery, barring highly improbable scenarios.

    • Christian Hedegaard-Schou

      Sure it can, and does. All you need is some gunk to keep the firing pin in the forward position and you can get an OOB slam-fire.

      • justin

        the article does not mention it slamfiring, that is why i did not address it. if you look at the 5th and 6th pictures you can see a bolt and firing pin respectively.

        the bolt has a raised ridge on the lower portion of the breech face that holds the rim of the cartridge away from the firing pin if it should become stuck forward. this only reduces the likelihood of a premature detonation of the primer. this ensures that a strike can only happen in the last 1-2 millimeters of travel as the chamber stops the cartridge from moving forward anymore. this is similar on open bolt submachine guns like uzi’s, etc… this potentially exposed portion of the case is thicker to accommodate higher residual pressures while extraction occurs.

        the firing pin/spring can be seen to apparently be clean and free from gunk, although stuck firing pins can happen, it seems as though it was not the case here.

        a slam fire likely would not produce a kb due to the safety features described above. however there are no safety features to accommodate overcharged ammo in a blowback firearm.

      • jamesone

        9mm Ar pistols have a decently heavy spring with the firing pin. It is not likely to get a slam fire from a firearm that has a spring loaded firing pin.

    • Giolli Joker


      BTW, he seems to say that this happened on the first round of that brand… it’s quite safe to assume that it was in a newly inserted magazine, so it was chambered manually or by releasing the bolt. He doesn’t imply that the gun slam fired, so its highly unlikely that we’re dealing with out of battery discharge.

  • Mark_KTO

    That primer is not merely dented, but really, most sincerely dented. Kaboom is what is supposed to happen when the primer is smacked. How is that the ammo’s fault?

    • sauerquint

      That primer is the first thing I noticed. That can’t possibly be considered an ammo related failure.

  • WFA

    Good analysis by Justin.
    So would a rotating bolt design with gas tube (as used SIG MPX) allow a wider range of ammo to be used, assuming the gas port design was sized accordingly and allow the use of a relatively light weight component assembly?
    Is this the reason SIG chose to use this complex system over a simpler blowback operation?

    • justin

      basically, yes… that design could allow for over the beach, barrel full of water, conditions and still function, or overcharged ammo, without a kb, could! however, on gas operated guns the port size, bolt mass, spring weight, and port position, bolt travel, hammer spring weight, hammer mass, etc… all have their own “tolerances”

      i.e. an ak, has way more bolt carrier travel then what it needs to operate. that allows for a greater time for the next round to move up in the magazine and allows for weaker springs as they age, it allows for higher carrier speed for stripping the next cartridge as it has more time to accelerate from the trunion to the cartridge rim, it allows the action spring to absorb more force before the carrier slams into the rear trunion, and allows for an aging spring. etc…

      so, if sig added additional “tolerances” then potentially it could more reliable than blowback firearms.

      however pistol cartridges are short and a locked rotating bolt adds length to the distance the cartridge must travel from the magazine to the chamber, due to the bolt and barrel locking surfaces being placed between the chamber and magazine, this can reduce reliability, especially with hollow points, but sig may have introduced a fix to that as well.

  • Lance

    Looks liek he was using Pakistani 9mm imports thats the reason for that KABOOM!. Stay with US and NATO ammo makes for a better chance of a long weapons life.

    • the ammo addict

      ZQI is not made in Pakistan, it is made by MKE in Turkey. Turkey has been a NATO member since 1952. MKE makes NATO-spec ammo for the Turkish military and sells the same ammo here in the U.S. under the ZQI brand.

      • Greg Thompson

        The 9mm ZQI has been good ammo for me so far

  • Joe

    Possible soft primer with firing pin bounce?

    • the ammo addict

      That is a valid concern with 9mm ARs, but the ZQI 9mm is made to NATO specs and has a fairly hard primer. I suspect that either the bolt was slightly out of battery, but still close enough to fire the round. The owner didn’t mention if this was a slam fire, but I doubt that it was since it was on the first round of a fresh magazine – a slam fire in that instance would be very much worth mentioning.

  • DiBs

    Something else to note for those who believe rifles in their original designs are superiorly safe: I have personally seen AK47’s and RPK’s fire out of battery(and somehow survive). I’ve fired an RPK (Iraq manufacture, I think) that fired out of battery regularly, leaving the front half of the brass in the chamber each time. It was a collossal PITA to use. I’ve also used an AK47 that doubled ( more like quintupled) frequently due to wear and it too would fire out of battery at times. But still, that PPSH can goto hell, even though I harbor no bad feelings for other Soviet weapons.

  • Geoff a well known Skeptic

    I don’t understand the “AR pistol” purpose or “philosophy of use.” And a 9mm of that size, is silly compared to a SWaMPy 9. Geoff Who is skeptical.

    • Mark_KTO

      IMO, it’s purpose is to sell units and its “philosophy of use” is to satisfy wannabeism.

  • FedUpTxn

    I fired some ZQI ammo in 7.62×51 that had much more recoil and flash out of the muzzle of my FN FAL. Several experienced shooters all noticed the difference in ammo. I really question QC at ZQI’s facility, as this certainly appeared hotter than comparable ammo.

    • Greg Thompson

      The 9mm ZQI has been good ammo for me so far. The pressure is somewhere between standard and +P but not equal to either. It’s 9mm NATO

  • toms

    ZQI is terrible ammunition. Has some of the worst tolerance controls and SD ever. I had two cases of .308 and 5.56 from a couple years ago. It was horrible ammo. Failures to chamber. weak and alternatly hot rounds put it at the bottom of the pile for use in desperation. Ammo related I suspect.

    • superflex


  • spotr

    Perhaps it was not out of battery when the round was fired.

    It may have been a previous round barrel blockage issue causing extreme backpressure as the 2 rounds left the barrel much slower than one round would have. The bolt would have moved backwards faster exposing the now unsupported weak sides of the brass case to high pressure.

    • Wouldn’t you expect to see a bulged barrel, then?

      • spotr

        It’s possible.
        Most 9mm AR barrels are much thicker than 9mm pistol barrels and may be able to take a lot of pressure before any stress failure (bulge) forms.

  • Seth Hill

    Looking at the first image and the second image, it seems to me (I am not an expert by any means) that the round (first round in a new magazine) started to chamber or partially chambered (as evident in the first image and reinforced by the second image), notice that the “neck” of the case is intact which I would think would not be the case in an out-of-battery discharge. Having read over the above text and the forum thread a couple times, I am not convinced this is an out-of-battery issue, technically speaking, as the round partially chambered. There is no clear indication from the poster as to when it went boom, I am leaning towards when he pulled the trigger.

    Here is how I think, based on the images, what happened: Inserted mag with ZQ ammo, released bolt, round stripped from mag and round partially chambered, trigger pulled and round goes boom. I am wondering if the round, or even the lot that this round came from, was out of tolerance for a 9MM? I’d be curious if he used a micrometer (which he states he doesn’t have) on the other rounds what they came out as compared to other brands such as the Fiocchi?

  • Kivaari

    That is not an AR15 PISTOL. It has a carbine tube, that accepts an adjustable stock. It is a SBR, and I would not be surprised if the ATF knocks on his door. It is probably a good idea to swap out the carbine tube for a pistol tube, just to be safe and in compliance.

    • jamesone

      You can build a pistol with a carbine buffer tube. Its legal always has been, but don’t be caught with a loose stock laying about near by.

      • Kivaari

        That’s the thing that could bite you, knowing how difficult the ATF can be. Individual agents can really take a hard stance. I would not do it, just because the agents will conclude that if you have a stock on one rifle it will make its way to the pistol. That said, having a legal pistol and a carbine, is just two pins away from swapping them around. I am tempted to buy a SIG pistol and doing the ATF Form 1, but I don’t like the wait and probably wont live long enough more to have fun with it. I had 7 NFA weapons at one time. I regret selling them.

        • jamesone

          E-file form 1 make a trust to do it and shave the wait down to a month. Also don’t have extra parts around and you can’t convert it. If it’s already on a firearm (another ar) you have no intent to mfg as it is already on another firearm.