will ammo explode in fire


January 21, 2003, 07:42 PM
I was at the range tonight and the guy running it told me that ammo such as pistol and rifle would not explode if you threw it in fire. He said it would just sort of fizzel. Will ammo explode if it is in a fire?

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January 21, 2003, 07:59 PM

Ammunition is dangerous when held in a chamber and fired under high pressure down a barrel. This causes the velocity & destruction.

Loose cartridges will cook off & pop their bullets somewhat like a boiling pot popping it's lid. Perhaps not pleasant but far from overtly dangerous.

Gunpowder and modern 'propellants' are just that, they burn fast & generate gasses. They are not explosive.

Bullets need to be fired within a constricted space (like a gun) to be dangerous.

January 21, 2003, 08:15 PM
I know that .22 rimfire will pop with pretty good velocity in a 55 gallon metal trash barrel when subjected to fire. It takes about 5 minutes before they start to pop.

Kahr carrier
January 21, 2003, 10:22 PM

January 21, 2003, 10:29 PM
I've observed 5x56 cook off and move the case (and shrapnel) at a pretty good clip.

The bullet stays; the case moves.

January 21, 2003, 11:23 PM
I work as a firefighter and have been in a number of fires where live ammo was cooking off. The first time, I was concerned, but everyone told me to ignore it. A friend of mine was hit in the chest with a bullet from a cooked off round at a fire. It didn't even hurt.
They don't just fizzle. There is a report, and the bullet does fly though the air assuming that it was sitting out in the open. But the bullet has very little velocity and I have never heard of anyone being injured as a result. Of course I have to add the disclaimer that this doesn't mean you should do it on purpose to see what happens. It doesn't mean that the next time you get drunk around the campfire at hunting camp that you tempt fate. You may be the one guy in a thousand that does get hurt through some freak turn of events.

January 22, 2003, 12:08 AM
One of my friends is a volunteer fireman. They have holes in the side of one of there fire trucks from exploding bullets. I think someone parked the truck a wee bit too close to the burning house.

January 22, 2003, 12:16 AM
If ammunition cooking off in a fire put a hole in a fire truck, then the ammo was almost certainly chambered in a firearm (or in a revolver's cylinder) when it cooked off rather than just being in boxes or loose. (If the round is chambered, you get a thermally induced gunshot rather than just a firecracker.)

American Rifleman actually tried cooking off various types of ammunition and wrote up an article on it a few years back. IIRC, none of the fragments would penetrate a fireman's coat (they tested it), but the primers were going fast enough to cause eye injury if you weren't wearing goggles or a mask, and I'm sure the fragments would sting if they hit bare skin. The yield strength of the unsupported (i.e., unchambered) case is too low to develop significant pressure; it just vents.


January 22, 2003, 12:16 AM
Back when I was a voluntee fireman I was at a house-trailer fire where some ammo was cooking off. The Agressive Department boys had used their fancy new circular saw to cut a large hole in the side of this trailer in order to put the wet stuff on the hot stuff. As they peeled the metal down I got too good a look at some pretty impressive fireworks.

Nothing hit me or anyone else, and it might not have hurt if it had, but what I saw made me think that I didn't want to be doing interior work next to any ammo. Everyone with a good view through the hole on that fire did a pretty good job of disappearing quickly.

Bartholomew Roberts
January 22, 2003, 11:49 AM
WARNING: Lots of things mentioned below are relatively dangerous practices that I wouldn't advise now and I am glad I didn't learn a harder lesson. Impressionable young minds beware.

Well, it turns out I've done some experimentation on this issue myself in my younger/bolder/not so smart days.

I was sitting over at a friend's house drinking beer and cleaning guns after a day of shooting. He asked me to pass a box of ammo that was sitting on the coffee table and as I did, I moved it over the lit candle on the table. He reprimanded me for this as he felt there was a danger of the round cooking off from this. I maintained that at no time had I placed us in any danger. I stated my belief that the powder ignited at way too high a temperature for us to be at risk from a mere flame.

Being the carefree rocket scientists we were, we decided to put this to the test by pulling the bullet from a .22 and dumping the propellant into the candle to see what would happen - no safety goggles, no thoughts about dumping propellant into a fire on the coffee table... just an intense scientific curiousity ;)

Well, we dump the propellant into the candle and.... nothing. Absolutely nothing happens. Both of us being kind of entertained by rapid combustion, we were a bit disappointed. We expanded our hypothesis a bit... obviously the powder burns at a really high temperature and is stable; but what about the primers? Could passing them over a candle represent some danger?

We took the empty .22 casing and some needle nose pliers and throwing caution to the wind, stuck the casing over the candle flame (the same one we had just dumped all the propellant in). Well, after about 2 minutes we were both surprised and frustrated and how difficult it was to make these things go... BANG! The primer finally detonated - not sure whether it made the powder go or not; but it blew candle and hot wax onto the ceiling and all over the living room (as well as the coffee table and assorted frou-frou stuff).

From upstairs we hear his wife asking "<name deleted for posterity's sake>, what was that?" to which my quick thinking friend replied in his best soothing voice "Nothing honey!"

All eyes and ears accounted for, brass case intact in this case; however the mere proof that I am still alive and relatively uninjured should not be taken as evidence that all of my methodology is safe or even sound :D

January 22, 2003, 01:06 PM
My son's friend, a fireman, entered a burning barn where a loaded 22 rifle was located. Heat caused the rifle to fire. The bullitt hit him in the chest. He got full honors, draped fire engine, bag pipes and all!!


January 22, 2003, 01:28 PM
I confess, in my youth I've dumped a handful of .22lr in the campfire to watch the uninitiated scatter.

The pop. Occasionally the would blow chunks of wood or coals out. Nothing or no one was ever injured in any of my pranks.

I don't do this anymore though. Murphy is bound to catch up to me sooner or later. A hot case poping out of the fire could cause serious eye damage. But I'm relatively certain penetration of a bullet into human flesh is highly unlikely unless chambered. But lets don't risk it anyway.

January 23, 2003, 12:14 AM
Simple physics...the case is going to move away from the bullet because the case weighs less. Assuming, of course, that the powder actually "explodes". As lots of folks have noted, fizzles are much more common.

And my own experiments decades ago confirm the fact. :o

January 23, 2003, 02:05 AM
Thank you for starting this thread, michiganfan!!

My friend and I wondered the same thing, but I felt stupid for asking it. Now, I don't have to go through with actual experimentation!! :D

January 23, 2003, 07:55 AM
"Simple physics"

This is all assuming that the loaded round of ammo was lying out somewhere like on a table with no obstructions to influence the path of the projectile. . However think about how your ammunition is stored. Usually one end or the other is going to hit something right away like a shelf, or the box it is in. One reason why ammo in a fire isnt' a concern is not only because it is going off at very low velocity, but what are the odds of it having a clear path to you ?

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