Double charged

Yesterday I invited people to guess what this was:


chiefjabboby, using some rather flowerily language, got it right. Drew Rinella was more straight forward with a more complete, and correct, answer.

Below, on the left, is a normal primer which has been fired. The primer above is in the middle below. Most of what is left of the case is on the right. The rest of the case is stuck in the chamber of my STI DVC Limited (chambered in .40 S&W).IMG_0795AllCropped

I strongly suspect I got a double charge in one of my reloads. I didn’t think it was possible. It’s true, as I told myself when I started using this load, that a double charge would not allow the bullet to be fully seated. But I didn’t actually try it.The bullet compresses the double charge and the powder pushes the bullet part way out. But it’s only about 0.040 over the usual overall length (OAL). So, it’s quite possible I overlooked this during my final inspection.

The magazine was blown out of the gun and forcibly disassembled. This was essentially all I could find of the pieces. Note the spring is all crooked. What doesn’t show up is that the feed lips are quite a bit wider than a normal magazine.


There was some damage to the gun. I had to hammer it to get the slide open and the ripped apart shell casing out. I suspect the slide is beyond repair. The ejector pins were sheared off but it’s possible they were broken before the incident. The extractor was loose in the slide and the metal below the head of the extractor was pushed down and slightly torn:


I was not hurt but there were strange smoke patterns on my hands where gases came out of all the gaps between the slide, frame, and grip:


My face got peppered with tiny bits of something and stun for a few minutes but it did not break the skin. I had a slightly shadow on my face around my safety glasses giving me a bit of a raccoon appearance.

I disassembled the gun to examine everything carefully. Here is what a mostly disassembled STI DVI Limited looks like:


I plan to reassemble it and ship it off to STI to see if they can repair it. And before I use any more of  that ammo I’m going measure the OAL on every cartridge (I think I can use a case gauge). I have a backup gun which I used at a USPSA match today. And I expect I will be using is for a quite a while. STI is notoriously slow in turn around time and I may have to buy a brand new gun. And the last time I checked the wait times were quite long for new guns.

I put about 45,000 rounds through it. This is more than the approximately 40,000 rounds I got out of my STI Eagle 5.1 before it had a serious failure and became my backup gun.

It’s probably time for me to buy another gun regardless of whether the DVC Limited can be repaired or not. Heavy sigh…


37 thoughts on “Double charged

  1. Glad you are OK.

    I was wondering:
    Is 0.040″ difference in OAL going to be a reliable enough differentiator?
    Would the weight difference of a double charge make a better “tell”?

    Maybe both?

    Dis-assembling ALL that batch of ammo would be a pain, but I would probably go that way, and try to re-use the components.

    • I suspect that weight would not be a great indicator of a double charge considering the usual variability in weight of pistol bullets and cases. The total could swing a full charge weight in either direction.

    • I think I have about 3000 rounds I would have to disassemble.

      The variation in the mixed brass weight will hide the 5.5 grain delta in powder weight.

      The OAL varies no more than about +/- 0.002″.

  2. I was born in the mid ’80s and have only been reloading for 3 years. Bwahahahahahahahahahahahaha!

  3. I weigh all my carry ammo, but it’s all from the same box, usually. Variation runs 2 grains or less. Powder charge would be around 5 grains or a little more.

  4. I’m basically a novice, so apply salt to this, but… I have a case gauge, which does a nice job checking case diameter, and case length (to the shoulder) but I don’t think it does much for OAL. I could examine it more closely, but the fact that it has a bullet-size bore all the way through suggests that an overly long cartridge wouldn’t be caught that way.
    Maybe other gauges are build differently. It certainly would be possible to build a gauge that checks all the dimensions on the SAAMI drawing, including length. That would be harder to build, I think.
    Another consideration is that the max OAL isn’t necessarily the max for your particular load, if your bullets are shorter than the max length bullet. I think what you need is to check the nominal OAL for the bullet you have. A micrometer set to the max you expect, acting as a “go” gauge, would be a quick method.

    • You are correct about typical case gauges. I was going to temporarily (probably with tape) attach a washer or some other disk of the proper thickness to the bullet end of the gauge such that an over charged cartridge would not fully seat into the gauge. But I like your idea better.


  5. I had this happen in a custom .45 acp 1911. Peened the frame and slide a bit, ruined the magazine which was ejected, broke the grips into pieces, and made my hands feel like they’d been hit with a baseball bat. Shipped the gun off to the builder and he had it back to me in three weeks good as new. I’m lots more careful these days.

    HTH, sv

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  8. Rather than fretting over the long ETC for the STI, why don’t you switch to a class that allows use of an ordinary EDC gun you already have?

  9. Factories used to weigh every round. I’ve seen a picture of what we manufacturing engineers call a “dial” machine, i.e. a turntable. This one had about 100 beam balances of some sort on it, automatically loaded and unloaded. (Yeah, that was Korean War Era, but I’m that old.) I dunno if they still do that, but at that point in time it was considered an essential quality control step.

    Doing 3000 rounds would be tedious on any sort of scale that we would own, but I once did more than that for a .22 rimfire study, so it can be done.

    • If all the brass was the same weight I would consider weighing it. But it’s from a variety of manufacturers. I would have to sort by headstamp then weigh it. I think measuring the length with a go/no-go gauge will be faster.

  10. I remember reading about how IPSC shooters in the late 70’s early 80’s pushing .38 Super to very high pressures trying to a Major power factor.

    I think it was Mas Ayoob who writing about why a lot the top shooters grew beards to hide “Super face” from when their guns suffered an incident like this.

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  12. Happy to see you’re around to tell us your story. It can and eventually happen to most of us reloaders. This does give me something to think on.
    I had this happen with my 270 once. They weren’t my reloads but some unknown source. A friend of mine gave me a couple of rnds to test that his brother reloaded. It wasn’t a pleasant experience. Blew the bolt past my right eye and shocked my right arm into numbness. Was thankful it didn,t rip off part of my right cheek or worse kill me. The Lord watched over me that day.
    This is why if I don’t know who loaded it I don’t shoot it.
    My rule of thumb, I trust only my reloads.

    • I think the proper term for other peoples reloads should be: reloading components.

      Surprises can be fun under certain conditions. Ammo should have no connection with this.

  13. I reload 9mm. and a double charge puts powder all over the bench. Basically can’t do it.

  14. Do you NOT weigh each reloaded round? I mean Really, anyone who reloads and has such a lock of attention to detail, needs to learn how do do it right…..

    • Hate to break it to you but with many pistol loads the weight of powder is not statistically significant compared to variation in the other components. Had a single double charge I caught years back loading 45. Weighed the round along with the 100 before it. There was no measurable difference in Mass that could have identified another double loaded round in the proceeding run. I threw out the entire batch just in case.

  15. What reloading equipment do you use? Are you verifying your powder drop say every 20 or 30 rounds? Is the brass that you’re using to reload picked up off of an action range? Who’s to say that that brass wasn’t used up before you even reloaded it. Try double charging the brass and see if the powder doesn’t spill over the top. Don’t just assume it was a double charge. An under charge is just as bad. Did you load on major or minor PF? Just my 2 cents.

    • I verify the powder drop at the start of every reloading session.

      My reloads are low to mid-range in pressure so old brass shouldn’t be an issue.

      I do double charge a sample when I work up a load to see if it would still have room for a bullet (read this post carefully, I already mentioned this).

      I doubt it was an under charge because there was no swelling of the barrel.

      I load both minor and major. This was from major PF load supply.

      • I had this happen. Hurt like hell. Like catching a baseball batt.
        I quit picking up range brass. There no telling the condition of the brass. I buy it from indoor ranges although it claims once fired. What I’m trying to say is it don’t trust any brass that you have.

        • This didn’t hurt my hands even the slightest. Just put some soot on them.

          I pick up my own brass and buy used brass (supposedly once fired).

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  17. I had the same thing happen with my Glock 40. Apparently the glock does not have a fully supported breach and causes a stress on the case. after a few reloads it is to weak to support the pressure. luckly i was loading coated lead @ 1080fps unfortunately still destroyed the gun….

  18. Re serious pressure: I remember reading in discussions about propellants, or perhaps about explosives, that detonation depends on the explosive being confined. And that if it’s confined more effectively the detonation power goes up.
    So that would suggest the effect of a double charge isn’t just that you have 2x the energy. Instead, the fact that it’s more confined (jammed into the cartridge rather than loosely packed) encourages detonation instead of the proper fast combustion you want.

    • I’m not sure the energy is more than 2X (laws of chemistry and thermodynamics come into play). But the burn rate, and ultimately detonation velocities, will increase. This increases the peak pressures and will increase the damage.

      • Yes, my wording was sloppy but that’s what I intended. You have 2x the energy, but that’s not the whole story. The burn rate is higher so the peak pressure is increased by much more than 2x.
        Come to think of it, in a lot of physical effects it’s peak power that matters, not total energy. The total energy in a lightning strike is not all that large, it’s the peak power that is an issue. The moderate total energy is why lightning rods don’t (usually) evaporate.

        • It’s possible there is increased energy. With the higher pressures the combustion products could change. For example, perhaps there is more complete combustion of the carbon (less CO and more CO2). So don’t rule out increased energy but I agree the dominate contribution will be the increased peak pressure.

  19. Joe, I had the same thing happen to me with my STI edge. I generally use range brass. Not so much damage to the gun, but I will go back and recheck this after reading your detailed post. Thanks for that, by the way.
    I initially suspected a double charge, but am very conscientious about things like that too. So I also wondered about two other possibilities:
    1. That particular piece of brass had been fired in a Glock with it’s unsupported case head, maybe more tha once, allowing the head to shear near the base. The relatively clean, and straight separation at the head suggested this. But would a case head separation account for the other damage to the gun?
    2. A hairline crack in the case mouth that eliminated a tight crimp, and allowed the bullet to be jammed deeply into the case during the feeding cycle?
    Any thoughts would be appreciated.

    • In my situation I dismissed the weak brass hypothesis because of the extreme overpressure signs on the primer. But I didn’t consider option 2: the bullet being seated far too deep.

      I don’t think option 2 is likely. I use a powder charge of 5.5 grains of CFE Pistol with an OAL of 1.132″. The minimum charge is 5.4 grains with a OAL of 1.125″ (Hornady gives this for a Hornady XTP bullet instead of the Montana Gold JHP I am using). And the maximum charge is 6.0 grains. So, I’m using something that is barely over the minimum. Even with a OAL much shorter I don’t think it would cause that much pressure. I am also inclined to believe I am much more likely to catch a damaged piece of brass than a double charge.

      There is another reason for the double charge hypothesis having more weight (no pun intended) with me. I’ve been using very cheap, supposedly once fired, brass. As I reported last year I have problems with the brass from this supplier, Palmetto State Armory. Frequently, the primers fail to come out of the brass whole and break off in the primer pocket. The brass is cheap enough that even losing two or three percent (I haven’t actually counted the number cases I have to throw away like this but I suspect it could be as high as five out of every hundred) it’s still a good deal. But it does disrupt the reloading process. I remove the bad piece of brass, rotate the shellplate to the next position, put in a new piece of brass, and cycle the press as normal. If I forgot to the rotate the shellplate I would get a double charge. If it was a double charge, this is the mostly likely reason it happened.

      I have decided to stop getting my brass from Palmetto State Armory. I searched for another supplier and found one that sells used brass for essentially the same price and I ordered 2,000 rounds as a sample to see if the quality is better.

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