.50 cal KABOOM

Last month a man was seriously injured after a cartridge was fired out-of-battery in his BOHICA Arms AR-15 .510 DTC rifle upper. The .510 DTC is one of those .50 BMG equivalents designed for countries where the BMG is banned. Despite the name, it is .50 cal.

Firing pin almost penetrated stock/buffer tube
part of the case can be seen at the back of the receiver (next to the bolt).

One of the guys parents posted this at CalGuns forum …

Sunday a surgeon spent 2.5 hrs working to do hopefully the best work available to repair the damage. My Son, according to the surgeon had four broken bones and some ligament damage to his left hand, the one he was holding the gun with just in front of the chamber. If you notice the hole on the side of the I believe chamber is a vent, that’s where he received a good amount of schrapnel that broke his hand. The bolt lever was being pushed by his right hand/palm forward when the bullet discharged before the lever was locked into place. The result was a severe laceration to his palm but not as devastating as the damage to the left hand.

I met him with his mother and our daughter, his sister in recovery after his surgery he was quite depressed but glad no one else was hurt. His account of the event was the same Sunday night as the sedation wore off as on Monday evening when I visited him. No hammers, no channel locks, no tools no hang fire only hands.

We don’t know what exactly caused this unfortunate event to happen. I’ve been in contact with the mfg. on Monday and he seems quite concerned as I would be if I was producing an item like this. We will try to work together and determine what caused this event.

[ Many thanks to Marshall for the links. ]


There is thread at ARFCOM about the incident (Thanks to JH1990 for the link). One posters said …

I was not at the range when this happened but I spoke with the range staff last week and they pretty much explained exactly how this happened. The guy was using new reloads that weren’t exactly fitting well into his chamber. Dude was slamming the bolt handle with his palm trying to get the cases to lock in. The guy was also slamming the bolt forward full force from the rearmost position back and forth trying to ram the cases into chamber in an attempt to squeeze the rounds in so the bolt could close. Finally, on one of the attempts of him doing this, the possibly stuck firing pin rams into the primer and explodes the round when he slams the bolt forward (zero lug engagement hence the KB) and shooter puts himself into a world of hurt.

The firing pin may have been stuck because the bolt handle was overtourqued (apparently it warns about this in the manual).

Another theory is a hang fire situation where the round detonated as it was being ejected.

Others have suggested that a faulty or modified trigger group bypassed the safety system (which prevents the hammer striking the firing pin before the bolt is fully closed) and the force of slamming the bolt closed caused the hammer to fall detonating the round before the lugs where engaged.

This photo is interesting …

It seems the bolt was forced all the way rearwards and then bounced back.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • JH1990

    Anyone interested should read this thread. Lots of good theories and you can learn alot about the design. It did get locked cuz of some jackasses but still a good read.

    • JH1990, thanks for the link. I have updated the post.

  • SpudGun

    I’m not sure who is exactly to blame for this ‘ka-boomery’, as all of the evidence is anecdotal at this point.

    However, the number of FTF, FTE, AD, etc. that are posted on the various forums and blogs always seem to have the words ‘hand loads’ and ‘reloads’ in them. This could be construed as a pattern.

    Hopefully this incident will be investigated fully to find out the real cause.

  • Bolter

    My usual refrain: don’t use reloads. I know a lot of people think they are experts at this. Fine, shoot them yourself. Stay well away from me and other people on the line. Don’t buy these at a gun show or store and shoot them. You are playing with fire. You don’t know who made the ammo, you have no idea about quality control, and you have no recourse for liability if the round was manufactured negligently. Second, my grandfather used to say “Don’t force it.” Good advice for life. If it does not chamber easily, please don’t try to slam the bolt into battery. Thankfully the injuries weren’t more serious.

  • Shootin’ Buddy

    I feel sorry for Californians.

    No matter the state of your gun laws, one needs to eschew conversion firearms.

  • jdun1911

    Here is the summary of the cal thread via:

    1) gun blows up

    2) witnesses say they see shooter hammering furiously on rifle

    3) pictures of 3 hammers shown

    4) witnesses harassed/attacked and recant/revise the hammer part of their story

    5) older separate post in another thread about shooter hammering on rifle found

    6) possible picture of hammered bolt handle posted

    7) picture redacted or bandwidth possibly exceeded

    8) thread locked


    About ten years or so and I think I posted the story here once. A .50 single shot .50 cal rifle went KB!. The blot flew backward into the shooter chest then embedded its into the range wood cabin. IIRC he didn’t survive.

    If the Ace skeleton stock didn’t stop the firepin, he would have been dead. Someone was watch over this shooter. Very lucky indeed.

  • Aurelien

    Fun fact, the .510 DTC is french-developped and made.

    And the acronym DTC could be understood as the french meme meaning ‘dans ton cul’, roughly translating as ‘up yours’

    Isn’t that a cool name for rifle ammo ?

  • Lance

    Yeow dangerious. Always ceck your firearm before you shoot.

  • jdun1911

    It’s probably not the firearm fault but the ammo and/or user error.

    While I never reload .50 cal before I have a lot of years in reloading.

    Brass will expand in width and length when you shoot. You have to resize and trim the brass each time in order to reuse it. Resizing can take some effort depending on how big the brass size. For example it will be easy to resize a 9mm then a 300WM brass. Resizing a 50 cal brass might be an undertaking because it takes a lot of effort to push the .50 cal case into and out of the resizing die.

    Trimming brass case to the original length is a must. From my personal experience, most brass will stop to expand in length after the 4th or 5th reloads. I’ll still go through the trimming process tho to make sure it is in the proper length.

    It is possible that he doesn’t know how to reload or did not resize the .50 cal brass case properly.

  • Burst

    In summary:
    nothing can be made foolproof, as long as there are fools.

  • Whatever

    It looks like this rifle fired out of battery for some reason. From the last photo you can see a big dent on the edge of the bolt lug, like it was just being closed when the round went off. It’s hard to say more than that from the few pictures shown.

    Given that this rifle is a push feed and there’s no ramping on the bolt lugs to give a mechanical advantage when closing the bolt, could the user have gotten a little too aggressive in trying to get the bolt to close? The extractor has to move over the rim of the cartridge, something that might be tough to accomplish without whacking on it.

  • Frank

    It seems that a lot of gunk would have had to build up to cause that firing pin to get jammed forward against the spring pressure. My hypothesis is that he had a misfire (common- need stronger hammer spring and or heavier hammer). He didn’t do the standard 2min or 1min wait time. He then rotated the handle to extract and boom!!! This is actually more probable compared to stuck firing pin/slam fire. Misfire is common, I have a 36″ DTC edm 50 MK-II and I reload. Tried heavy hammer spring- it reduced frequency of misfires but not completely. I will make sure my bolt handle end does not restrict firing pin movement, and perhaps get a heavier hammer next. WOW, I’m making sure I wait the full 2min on misfires. I have always moved bolt forward gently- intuitive. If you reload, make sure your brass cycles nicely before proceeding. How do you make sure someone does the powder charges right if you have them made? I doubt that was the problem but can you imagine a 140% max compressed powder charge. Not sure what would break first, gun or shooters shoulder. Time to reload yourself..

  • Frank

    Its me again. Picture shows firing pin retracted. So spring appears to be doing its job. Good luck and good shooting gentlemen.

  • jules green

    How do I unstuck the bolt on a AR 50? I safeguarded it by taking the firing pin out and putting the bolt back in. I was out for a year , when I returned the bolt released somehow and is stucked,I cannot take the riffle apart, the bolt doesn’t go fully forward nor can it be pulled back out. Any advise?

  • frank

    Does it have a casing in it? If not then it sounds like your extractor parts came apart and is jamming up the rotating bolt. Spray lots of WD-40, make sure it is rotated fully before striking handle backward with mallet. Looks like you may have to force it…

  • Jesse Lofquist

    Can you put me in touch with the injured party of this post, I also have been injured by a Bohica and am trying to resolve the issue and help make sure no one else gets injured, Thank You Jesse

  • Frank

    I zoomed in and looked at the picture of the ammo and made two important observations. 1- a couple of the rounds look like the primers aren’t seated completely. 2- I notice a couple of rounds look like there may be a slight bulge at the top of the neck. All .510 DTC are hand loads; it’s a wild cat round. If the loader was crimping the rounds and did not have exactlly identical brass lengths, it is very easy to overcrimp that round making it difficult to chamber. Combine the two- primer not fully seated being pushed by the bolt face, overcrimped case fitting tight being slammed into battery? Deadly combo. Just a theory.