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ammunition in a fire question

Discussion in 'General Gun Discussions' started by TOTC, Jul 10, 2009.

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  1. TOTC

    TOTC Member

    Jun 1, 2009
    St Charles County MO
    What happens when rounds cook off in a fire? I vaguely remember that not being a rifled barrel, they would not carry near the energy were they in a rifled barrel. I could be wrong, but I vaguely remember something about firemen's bunker gear would stop the slug from penetrating.
  2. General Geoff

    General Geoff Member

    Nov 28, 2006
    Allentown, Pennsylvania
    The slug wouldn't go very far. The cartridge casing is what would become the faster projectile due to inequity of mass (the projectile is typically heavier, thus the brass moves away from the explosion faster than the projectile).
  3. Tommygunn

    Tommygunn Member

    Jun 14, 2006
    Morgan County, Alabama
    From what I've heard, they pop off relatively harmlessly. The thing is, it's really the brass casing that flies off, as it's less massive than the solid lead bullet.
    Still, if the rounds are in a tight confined space, it might cause undesirable effects.
    But to REALLY take off, the round needs to be properly chambered in a firearm and the expanding gasses need to push the bullet down the barrel at designed velocities.
  4. RyanM

    RyanM Member

    Jan 4, 2005
    As above. I've also heard that sometimes the primers can fly out of the cups at very high speed, due to their light weight. And very thin-walled, tightly crimped rounds like .22 LR, can explode into fragments.
  5. SASS#23149

    SASS#23149 Member

    Jan 1, 2003
    the rifled barrel has nothiing to do with it,the chamber prssure build up is what gives it the oomph.
    The brass is held captive in the chamber,the pressure spikes FAST and the bullet is forced out the front end,barrel or no barrel.
  6. rcmodel

    rcmodel Member in memoriam

    Sep 17, 2007
    Eastern KS
    Here are photo's of some testing I did to answer the same question in my mind.

    Rounds were placed inside a loose 1" aluminum thin-wall tube for guidance, and set off into galvanized furnace duct sheet-metal.

    Test set-up:


    Impact, side one: The aluminum Blaser .357 case head completely penetrated the sheet-metal. The RF cases and some of the primers nearly did too.

    Impact, side two:


    Recovered rounds:
    The .223 round blew out the primer and all the powder burned out through the flash hole without the case exploding, or dislodging the bullet.


    Note: The thin-wall aluminum guidance tube was not even dented.
    Ammo loaded in magazines would almost certainly be fully contained inside the mags.

    In no case did any of the bullets have enough velocity or energy to hurt you.
    The other components are a whole different story!

    Primers & rim-fire cases are most dangerous, followed by pistol round case fragments.

    I think you would be in much more danger from exploding aerosol cans, paint thinner, lawn mower gas, and gas-grill propane tanks in the garage.

    Only a round actually chambered in a firearm would have enough velocity to hurt you when wearing FD bunker gear.
    It will have the full power of the firearm, just as if it had been fired normally. That's why it's not wise to store loaded firearm's leaned in a corner, or a drawer pointed at chest level!!

    IMHO: All ammo should be stored in GI steel ammo cans.
    They will 100% contain ammo fragments in a house fire, while safely releasing the pressure.
    That's what they are designed to do!

    Last edited: Jul 10, 2009
  7. Polar Express

    Polar Express Member

    Jan 27, 2009
    Soviet of Washington
    I remember a post about this a while back. Here's my take:

    I'm a profesional fireman, so it's my job to go in and put the fire out. A couple years ago, we went to a house fire where we heard the "pop, pop, pop" of live rounds exploding from inside the house - (lots of them). It was a one story house, on top of a daylighted basement, and the fire was in the main, entry level. While the unchambered rounds just pop off, and have very little energy, (our structureal firefighting 'bunking gear' would likely provide plenty of protection from any potential schrapnel) in my mind, the largest concern is different: Are there any chambered autoloading firearms in the fire room? If enough heat reaches through the chamber wall, to light off the round in the chamber, well, then you have a very dangerous condition, as our gear will NOT provide protection from a bullet traveling out the muzzle with normal velocity. When a round goes off when in the chamber, it behaves just like the trigger was pulled, so, in addition to sending a bullet down the bbl at normal velocity, it could also cycle another round into the chamber. Odds are, if the heat got hot enough to light off the chambered round, any rounds in the magazine would have already exploded, but you never know. While this is a lot of theory, during the overhaul (mop-up), we did in fact find a loaded and chambered "AK-style" - (SKS, AK, MAK90, it was all chared up and hard to tell exactly) with a full mag attached.

    So, if you hear a lot of rounds exploding, keep it in mind that there may be more to that situation that what you are hearing! And... get on the radio and let the incidend comander and dispatch know right away!

  8. Nate1778

    Nate1778 Member

    May 4, 2009
    Louisville Ky
  9. CoRoMo

    CoRoMo Member

    Sep 21, 2007
    Californicated Colorado
    rcmodel's experiment is very interesting. I've seen it before and the information he gathered is golden.


    Here is a video of Mythbusters cooking off cartridges in an oven. Like has been posted, the lighter materials (shell casing) are traveling faster.
  10. TooTaxed

    TooTaxed Member

    Dec 31, 2002
    Columbus, Georgia
    I once ran a test similar to RCMODEL's...but used a hotplate covered by a common cardboard box. Nothing penetrated the box, though one primer and a few small pieces of torn brass stuck in it. There weren't even any dents from the bullets.

    The reason I did my test was that I doubted a newspaper report about a supposed gun shot accident resulting from a cartridge accidently tossed in a fire. I so notified the police...:evil:
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