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I was minding my own business at the Range at Austin yesterday, sending lead downrange while testing out a red dot sight. The Primary Arms SLx RS-10 is an impressive optic (especially for its price) with lots going for it…but more on that later.

I was squeezing off a few shots at 10 yards when the pistol jammed.

Did that surprise me? Yes it did. I had mounted the RS-10 on a damn-near bulletproof FN 509 Midsize Tactical pistol. It’s the platform I use for all pistol red dot testing because FN’s MRD mounting system lets me easily mount virtually anything that goes on a pistol. It’s the best mounting system there is.

Then there’s the fact that the 509 Tactical has been a generally great gun in all its many forms. This particular one has nearly 2000 round through it with nary a hiccup…until yesterday when it wouldn’t go back into battery. And the slide was jammed tighter than Jerry Nadler’s pants after a dinner with labor lobbyists.

The pistol wasn’t the problem. This round was.

That’s an Armscor 147gr. round that I mindlessly loaded into a magazine along with scores of others. I’ve shot literally thousands of rounds of Armscor ammo over the years and never had so much as a hard primer. They’ve been very reliable.

But as you can see, this one is, uh, a problem. A slice of the bullet appears to have sheared off when it was loaded into the case, leaving that extra sliver of copper on the outside of the round.

That additional diameter obviously made it too wide to fully load into the chamber, causing the jam. It clearly wouldn’t go into battery and I couldn’t rack the pistol or remove the slide. The gunsmith at the range worked on it for about 10 minutes to gently back it out.

This is not a criticism of Armscor. The gunsmith who helped me said he’d seen the same thing in some Winchester ammo a few years back.

When you crank out tens of thousands of rounds a day, you’re going to get the occasional bad one. It’s inevitable. And it’s not that hard for one to slip through the QC process.

That’ll teach me to slow down a little and pay closer attention to what I’m stuffing into the Maglula. You might want to do the same.



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  1. were you loading in the dark? seems kinda hard to miss…
    and dan, this jenniffe above me here, are they unblockable? seems like a hovering spambot to be the first post.

  2. When loading a Glock 32 mag a few years ago, I noticed the bullet in one of the cartridges had been inserted upside down. I couldn’t fathom how that could happen. This was off-the-shelf American made ammo from a reputable manufacturer.

    • I *always* check ammo when loading mags. The most common issue I find is the bullet seating in 9mm. Sometimes (maybe one in every 100 rds with most brands) they’re pushed down too far and the edge of the case appears to be compromised.

      I also feel the edge of the case with my thumb. Depending upon the manufacturer, some lots are produced with their loading equipment a little out of whack, and the cases aren’t properly coined. The resultant sharp edge can prevent smooth delivery of the cartridge into battery if the angle of the gun’s ramp isn’t accommodating. If it’s not coined, I set that box aside for one of my Glocks that’ll eat up anything I toss into it no problem.

  3. ive found a brand new out of the box federal 5.56 55 fmj round with the primer missing
    ive found the same type of round made by winchester seated so deep in the case i couldnt believe powder wasnt falling out
    ive found 5.56 remington rounds with a primer in the pocket the bullet seated to the correct depth but with the tip canted off to the side like a millimeter or two
    since then
    i pretty much go through all my defensive ammo
    -pistol and rifle-
    with a fine tooth comb
    i first line them up on their side facing away from me to check for missing primers
    then i place them vertically on a flat surface and compare them all to each other looking for any flaws or inconsistencies

  4. Working the counter one day at a local indoor range a shooter came out of the range and reported that his gun was jammed. Went to the firing lane he was assigned and sure enough, couldn’t get the slide to come out of battery. Customer reported that the sound was a light pop when he pressed the trigger. Secured the firearm and took it to the shop area. Using a padded vice and a mallet we were able to get the slide to unlock and a full cartridge was ejected. Looking at the primer the firing pin pierced the primer and all that went off was the primer. The torn primer locked the firing pin which caused the lockup. Took a bullet puller and there was still powder in the the case and NO FLASH HOLE! When the primer went off their was no room for the pressure to release so it took the path of least resistance and blew out the strike face of the primer. Factory boxed ammo.

    • had that happen to me one morning as I was aiming at a deer…heard a little pop and the gun didn’t fire..when I attempted to eject it…[out the top..model 94]…the cartridge separated..and the powder hit me in the face as it spun backwards…..swear I saw that deer stick his tongue out at me before he slowly trotted away!…….

  5. I do my best to check all the ammo before I load a magazine. Sorry Dan I’ll never buy Armscor 223 ever again. Had several misfires in a box. I’ve heard folks having problems with 9mm but not mine. And my buddy bought the 200 38 4″revolver that broke. Trying to save $ 🙄.

    • had that problem with national sub-sonic…would eject the empty but leave the bullet in the chamber or worse yet part way up the barrel…sobering stuff!

  6. I got a Hornady Critical Defense with the primer installed upside down. I thought that was pretty strange getting past inspection. Hornady asked for a picture and the serial number on the box. Got another box out of it.

  7. I have a good name brand .38 round on my curiosity shelf that had the edge of the case roll in on itself as the bullet was placed. The big wrinkle will not allow it to be chambered, but I did see it or feel it before attempting to load. Also, a buddy had a .380 round that the primer self-ejected allowing the powder to drain.

  8. I’ve found a few defective rounds over the years. I thought they were hard to miss. I’m looking at them as I load the weapon/magazine. In addition, just tactile should expose defects. That’s how I usually find them.

  9. I haven’t had any bad rounds from stuff bought after the covid nonsense but I figure it’s only a matter of time.

  10. As a teen back in the late 1980’s I was shooting my dad’s Savage 99 .308 and heard a click instead of a boom. When he removed the round the primer was seated sideways & crushed flat! Never seen that before or since. It was the Hansen Ctg Co brand made in Yugoslavia. Shot quite a bit of that stuff. Can’t believe it didn’t go off at the factory when primed.

  11. I was shooting around 5000-10,000 rounds a year for about 10 years, or 7500 a year average. 50% was 9mm, 25% 22LR & 22WMR and the rest, 380, 40, 45, 38, 357, 327, and occasionally 45LC, 454, and 460; all handgun shooting. Had some 22 rounds with the bullet cocked in the casing, had some 22 rounds with only a primer; I watched the bullet bounce off the paper target!, it only dented it! Luckily it didn’t get stuck in the barrel! Had some 9 that wouldn’t fire, even after 2 or 3 attempts They were all Winchester branded products sadly. Once I had a 9mm round similar to this one, but I caught it before I loaded it. As I recall it was a Magtech brand.

  12. Get a Hornady or other brand SAAMI chamber gage/checker. Other wise known as the plunk test. However, Federal GMM 308 ammo of recent years will not go in my match chambers but it will plunk in the SAAMI gage. There is a burr on the exterior mouth of the cartridge. You can feel it with your thumbnail. The ultimate chamber check is your chamber. Ive asked my rifle smith several times to make me chamber checker using his match reamer but he’s too paranoid and wont do it.

  13. It is just good common sense to examine your ammo as you load your mag. But being imperfect beings, we sometimes make mistakes. Thankfully, I have not made one like that.

  14. I experienced the same thing with handloads in an early model Sig P220 .45 acp using the sharp shouldered H&G No. 68 truncated bullet. So what caused this? The Sig P220 in .45 acp was actually a reverse engineered 9mm model and the Sig Engineer thought he could get away with the empty fired case rubbing over the top round in the magazine during the ejection/loading cycle. As the slide reciprocates the fired case is being blown out of the chamber (the extractor does not extract an empty case when fired that is a myth, its blown out, more on this below). The rearward moving fired case catches or presses on the top round of the magazine on its way out of the chamber. The empty case ploughs a trench through a cast bullet with a sharp shoulder and when it hits the case mouth it peels the case mouth back like a banana. The now mangled top round in the magazine then is jammed into the chamber by the forward moving slide and naturally the round does not seat into the chamber but jams part way into the chamber.

    Although Sig could not have cared less about cast bullet handloads and like most companies will tell you it voids the warranty or the company liability with handloaded ammo what Sig did not know was the P220 can also jam with factory jacketed loaded ammo as well because of the fired case pressing down on the top round in the magazine. Sig then was forced to put an “interrupter” on newer made guns that presses down on the top round of the magazine.

    One must also be aware of “rim lock” when loading the rimmed .32 acp case. Getting the rim of a lower loaded round in front of the upper round will lock up the gun in the firing sequence.

    Loosely seated bullets can often be pushed down into the case during seating, often called “bullet setback”. This will often compress the powder charge in some cartridges causing a catastrophic detonation blowing the pistol to smithereens. Early in the ill conceived 40 S&W cartridge production the factories were loading the heavy weight 180 grain bullets with hot charges, leaving no airspace in the cartridge. Ammo companies should have known better! Bullet setback during the loading cycle cause 3 catastrophic explosions in 3 brand new handguns, a Browning High Power, a Glock and a Ruger (discontinued “P” model). This was reported on the back pages (on purpose) in Combat Handguns Magazine many years ago.

    I have also seen factory “bent rounds” and “dented rounds” jam up a gun in the feeding cycle.

    And as I mentioned above if you think the extractor extracts a fired round try removing the extractor on a P38 and then shoot it. It will function flawlessly

    • Please Clarify:

      1) I believe .32 Rim Lock will NOT occur if using FMJ rounds. Only the shorter Hollow Points
      will have enough extra space to give rim lock. Correct or not ?

      2) As to the bullet setback, I was under the impression that LEAVING an airspace would be
      the problem.
      So, a muzzle loader with the projectile not rammed down onto the charge
      would turn the firearm into a bomb instead of launching the bullet, due to the air space
      between the charge and the bullet.
      You say no airspace would be a problem.
      Please comment, as I would like to understand.

      • To Kevin
        In answer to your first question. It all depends which model and make of .32acp we are speaking of. Just out of curiosity I randomly pulled four .32 acp pistols out of my collection, a Mauser Hsc, A Walther PP, an Ortgies, and an FN 1922. Although it would be very difficult to do there was just barely enough room in all 3 pistols to slip a rim behind the lower round in the magazine but I must say it would be very unlikely to happen with fjm rounds as compared to the shorter 60 grain ammo. One must remember that a slight tipping of the 2 loaded rounds when loading in the magazine makes even more room for this to happen. And then there is the variation in rim thickness and diameter between brands of ammo.

        As far as muzzle loaders you are trying to compare apples to oranges as black powder and smokeless powder are two entirely different propellants. Smokeless powder is designed to burn at a controlled rate so that the much more powerful smokeless powder does not detonate (as long as its not compressed).

        I admit I know little about black powder and muzzle loaders but I do know that more than one loading manuel warns handloaders that when loading smokeless powder pressures can skyrocket when you have a compressed powder charge which of course can cause a detonation.

        I will now give you an actual occurrence of that happening. Fortunately it actually happened in a 9mm machine gun which was a much more robust a weapon than any pistol. I gave some handloads to a friend of mine and his machine gun had a steep feed ramp. In the loading cycle the round caught on the feed ramp shoving the bullet down into the case but it did enter the chamber. The result was a detonation that blew the cartridge case up like a grenade but luckily did not seem to have damaged the weapon. Bits of shattered brass could have seriously injured the shooter but the machine gun was well enough designed that it prevented most of the debris from flying out into the shooters face.

      • To Kevin

        Update and second test run with different ammo.

        I first tested with a very old box of Winchester Western ammo marked 71 grain fjm bullet. The second test was with a new box of Norma 73 grain fjm. Strangely enough even though the Norma bullet was heavier it was much shorter in overall length making it more likely that rim lock might occur.

        • remember having a round “mushroom” in my Sten…took it back to the guy who sold it to me…he looked it over …muttered something about “headspace” and slapped it in a drill press for a few moments…then handed it back to me saying “try it now”….oddly enough it never did that again!….

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  16. I purchased 500 rounds of American Eagle 357sig in 2015, first 50 rounds worked fine. The start of the next 50, first round went POP, (huh? squib? Yep squib.) pounded it out the front of the barrel, go back check all the rounds in the box, reload the mag, POP, (No way!??, Yep squib) pound the second one out (whats the chances’?) Third round. POP, go get the bullet puller, after 22 rounds and NO POWDER was pissed. Federal was amazing after I contacted them. Sent all the remaining rounds back. They sent me 500 new to replace the original and 250 for the inconvenience.


    • walking to a deer stand in the dark…loading the gun as you enter the woods…it can happen

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