# What happens when a bullet discharges outside of a gun?
**URL:** https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745
**Category:** Factual Questions
**Created:** [April 23, 2014, 4:58am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745 "2014-04-23T04:58:49Z")
**Posts on this page:** 16
**Page:** 1
### Author:  [@obbn](https://boards.straightdope.com/u/obbn)
#### Post date: [April 23, 2014, 4:58am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/1 "2014-04-23T04:58:49Z")
Hello Everyone,
See thread title. My thought is that besides a loud sound, not much. Without the barrel and chamber the pressure from the gun powder will just expand everywhere. The bullet won’t travel but a few inches or feet. I would think that this would be true for a spontaneous discharge or if the round was thrown into a fire, but say you took a hammer and hit the primer side of the case. Would the hammer provide enough pressure on the casing to cause all of the force to push the bullet? My guess if that without a barrel to channel the energy it would be all sound and not much else.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [April 23, 2014, 5:06am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/2 "2014-04-23T05:06:38Z")
We used to shoot at 22’s with a BB gun.
I wouldn’t want to stand in front of one… Even if the bullet energy was only 1/10 of what it would be in a gun, it’s still dangerous.
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### Author:  [@the\_diego](https://boards.straightdope.com/u/the_diego)
#### Post date: [April 23, 2014, 5:10am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/3 "2014-04-23T05:10:21Z")
The various anecdotes in gun magazines of bullets exploding on their own seem to point out the following:
1. The slug doesn’t travel fast and far. But it’s still dangerous (treat it like a slow but heavy shrapnel)
2. The casing rarely ruptures. Worse is that it’ll split from the mouth. But it could fly whole and injure.
3. Main causes of explosions are storing and/or carrying loose bullets with hot objects, 9-volt batteries, or sharp objects that strike the primer.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [April 23, 2014, 10:34am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/4 "2014-04-23T10:34:24Z")
Was sitting around a campfire once, when a buddy of mine (stupidly) threw a 7.62 X 39 round into the fire. It simply went “pop” like a firecracker.
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### Author:  [@racer72](https://boards.straightdope.com/u/racer72)
#### Post date: [April 23, 2014, 11:34am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/5 "2014-04-23T11:34:00Z")
Mythbusters tried various versions of firing ammo without guns. In most cases, the shell, being lighter, is what went flying. The bullet itself didn’t travel very far.
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### Author:  [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)
#### Post date: [April 23, 2014, 12:00pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/6 "2014-04-23T12:00:13Z")
I tossed a stripper clip of 5.56 into a fire once. Okay, I was in a pissy mood. 10 bangs, but no one got perforated. But I don’t recommend you do this yourselves. It still was a bad idea.
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### Author:  [@MrKnowItAll](https://boards.straightdope.com/u/MrKnowItAll)
#### Post date: [April 23, 2014, 12:27pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/7 "2014-04-23T12:27:54Z")
> [@racer72](#):
>
> Mythbusters tried various versions of firing ammo without guns. In most cases, the shell, being lighter, is what went flying. The bullet itself didn’t travel very far.
It should be noted that in one experiment they put cartridges in an oven, and in the case of one high-caliber round it inflicted some serious damage to the metal interior wall of the oven door. So, the danger exists. Probably not enough to kill you unless it hit in just the right spot (say, upside your durn head), but enough to send you to the emergency room.
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### Author:  [@skypig](https://boards.straightdope.com/u/skypig)
#### Post date: [April 23, 2014, 1:07pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/8 "2014-04-23T13:07:13Z")
The powder burning will still produce pressure which will follow the path of least resistance.
Either the projectile will depart (significantly lower velocity, as the pressure escapes easily, without imparting much energy. The case will rupture (I’ve found cooked off rounds at the site of a WWII Air crash like this. Possibly the projectiles were crimped in pretty well during construction.). Or the primer will depart the scene.
Or a combination of all three.
It’s physically impossible for the projectile to gain anything like the velocity attained when fired from a barrel, the case supported by the chamber.
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### Author:  [@sweeteviljesus](https://boards.straightdope.com/u/sweeteviljesus)
#### Post date: [April 23, 2014, 3:12pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/9 "2014-04-23T15:12:39Z")
There are a bunch of YouTube videos about this (sorry, I don’t have a search for you). I saw one the other day where a guy set off a .50 BMG round (a big round used in heavy machine guns and extreme range sniper rifles) in a microwave. Result: the round exploded, blowing the door off. The bullet dented the back wall (at which it was pointed) and bounced out the door. The case ruptured.
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### Author:  [@jharvey963](https://boards.straightdope.com/u/jharvey963)
#### Post date: [April 23, 2014, 5:28pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/10 "2014-04-23T17:28:20Z")
I remember reading in an NRA publication (yeah, I question the veracity, too, but it would seem easy enough to duplicate) that if you put bullets in a fire and surround it with a cardboard box, that the bullets (or cases) wouldn’t puncture the cardboard box.
Of course, the caliber of the bullet matters…
J.
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### Author:  [@staballoy](https://boards.straightdope.com/u/staballoy)
#### Post date: [April 23, 2014, 5:37pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/11 "2014-04-23T17:37:04Z")
Quite a few years back, I knew 2 middle school age brothers who placed a bullet (type and caliber forgotten) in a vise, and hit the primer with a hammer. The bullet had enough steam to hit Bozo #1 in the tummy while the shell case hit Bozo #2 in the thigh. Bozos’ parents had to take both to the ER.
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### Author:  [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)
#### Post date: [April 23, 2014, 6:32pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/12 "2014-04-23T18:32:00Z")
When I was a little kid, I found a .22 long and started smashing it with an old iron. ( like for ironing clothes )
I started on the bullet end and slowly worked to the back. I had flattened it pretty good & when I finally hit the base, There was what seemed a good bang under the iron. I never found the bullet and the case had blown a hole in the side.
- had it pointing to the right in front of me so I instinctively knew to not point it at some one. ( me ) Natural born safety instructor I do believe.\*
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### Author:  [@dstarfire](https://boards.straightdope.com/u/dstarfire)
#### Post date: [April 23, 2014, 8:41pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/13 "2014-04-23T20:41:12Z")
Mythbusters have tested this. What happens is that the lighter casing gets blown away from the bullet (which has more mass, and, thus, higher inertia). They tested baking bullets in an oven and were only able to break the ovens glass when they put in a .50 cal bullet.
As for setting it off with a hammer, you’d some sort of protrusion on the head, since the primer is typically recessed a tiny bit from the back of the shell. A flat hammer would just hit the back of the shell and wouldn’t deform the primer enough to detonate it.
Throwing bullets in a campfire isn’t deadly, but it will likely result in painful bruises and cuts.
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### Author:  [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)
#### Post date: [April 23, 2014, 8:57pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/14 "2014-04-23T20:57:17Z")
> [@jharvey963](#):
>
> I remember reading in an NRA publication (yeah, I question the veracity, too, but it would seem easy enough to duplicate) that if you put bullets in a fire and surround it with a cardboard box, that the bullets (or cases) wouldn’t puncture the cardboard box.
>
> Of course, the caliber of the bullet matters…
Wouldn’t the cardboard burn up in the fire before the bullet got hot enought to explode?
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### Author:  [@Telperion](https://boards.straightdope.com/u/Telperion)
#### Post date: [April 23, 2014, 10:14pm UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/15 "2014-04-23T22:14:06Z")
> [@kunilou](#):
>
> Wouldn’t the cardboard burn up in the fire before the bullet got hot enought to explode?
You’re gonna need a bigger box.
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### Author:  [@Baal\_Houtham](https://boards.straightdope.com/u/Baal_Houtham)
#### Post date: [April 24, 2014, 12:53am UTC](https://boards.straightdope.com/t/what-happens-when-a-bullet-discharges-outside-of-a-gun/686745/16 "2014-04-24T00:53:53Z")
My high school art teacher had one slightly odd eye. His story was that as a boy he fired a BB gun at the rear of a bullet. The alignment was good, and the casing flew back and hit his face. :smack: I don’t knw the caliber or how the cartridge was secured.