Exploding ammo

Factual Questions
#1

I have a couple questions about the “explosiveness” of normal handgun/rifle ammunition.

  1. If you were to shoot into an open crate of ammo, would it explode? And what would this explosion be like? One big explosion, or lots of little bangs?

  2. Are crates of ammunition ever stored in a way that protects them from this?

  3. Could you use a fully loaded clip in an explosive manner? For example, could you throw a fully loaded clip onto the ground and then shoot it to make it explode like a weak grenade?

  4. Does fire have the effect on ammunition that is normally shown in the movies? Or is a substantial amount of heat required to ignite a bullet?

#2

Modern gunpowder (smokeless powder) is a propellant, not an explosive. It does not detonate like nitroglycerin, it burns rapidly (deflagrates). The primers in cartridges contain a small amount of a shock-sensitive explosive. This ignites the main charge of smokeless powder when it is struck by the firing pin.

Shooting at a box of ammunition is unlikely to do anything interesting. Even if the bullet hit the primer on a cartridge. The powder would just ignite and burst the brass casing at a relatively low pressure. The case fragments and bullet would not have significant kinetic energy. A chain reaction is highly unlikely.

Don’t believe anything you see in the movies. These are the people that put a charge of black powder and a can of gasoline in every car that has a fender bender on screen.

#3

1) No. It’s possible one or more of the cartridges that your bullet strikes will ignite, but it won’t be a “chain reaction” sort of thing. Without being constrained in a chamber and barrel, a cartridge going off is actually considerably less powerful than when properly fired.

2) Not specifically, no. Commercial ammo is typically packed in carboard boxes, contining a seperator of some kind to hold individual catrtridges in an orderly fashion. No armor, no damage resistance apart from genral shipping packing.

Military ammo is somewhat better protected, but typically just against handling and transport damage, moisture and dirt/grit, and preloaded into stripper clips, belts, or magazines.

3) No. Chances are you won’t even get one cartridge to “go off”, and you’ll have ruined the magazine and it’s contents. If a cartridge did manage to “go off”, it would be slightly more powerful than a firecracker, but the bullet would probably not exit the body of the magazine.

4) Depends on which movie. Typcially, a centrfire cartridge tossed into a fire will simply reach an ignition temperature, go “pop” and throw the bullet perhaps two or three feet.

Again, if the cartridge is not constrained by a chamber and barrel, and the internal pressure is not allowed to rise as it wants (the powder burns faster the greater the pressure- little or no pressure, as if burning it in an open pile, and it burns relatively slowly, as in seconds, not milli or microseconds.) The pressure simply reaches the point the bullet is pushed out, the pressure drops, and the rest of the powder just burns away.

It’s not smart to put ammo in a fire, but it’s not “Darwin Award” dangerous either.

#4

Wow thanks, I had no idea bullets worked that way (although it makes perfect sense).

I seem to remember a movie/tv show where they take a large quantity of bullets, extract the powder, and make a small bomb out of it. Is this possible? (And bonus if anyone can remember what that show was…)

#5

What mks57 said.

I have been near some jackass that tossed a hand full of .22’s into a camp fire. It took about one minute for them to start to pop. They seemed to have about the amount of energy as if they were thrown by hand.

The only thing that I have noticed where TV and real life, as far as guns go, is the ricochet, especially when fired at water - this is not a good thing to. Oh yeah, toilet tanks are kinda TV like, TV’s don’t do anything good at all.

#6

And what Doc Nickel said too.

It is possible to use the powder to make a pipe bomb - I will not go in to it because it is illegal and not permitted to be discussed here.

#7

[QUOTE=Doc Nickel
Again, if the cartridge is not constrained by a chamber and barrel, and the internal pressure is not allowed to rise as it wants (the powder burns faster the greater the pressure- little or no pressure, as if burning it in an open pile, and it burns relatively slowly, as in seconds, not milli or microseconds.) The pressure simply reaches the point the bullet is pushed out, the pressure drops, and the rest of the powder just burns away.

It’s not smart to put ammo in a fire, but it’s not “Darwin Award” dangerous either.[/QUOTE]

The show Mythbusters did a segment where they made bullets “fire” by using them in place of fuses in a car. While ordinary currents did pretty much nothing, turning up the juice made the bullets explode with enough velocity to do damage to a manikin, through part of the car.

It was a pretty surprising result, a bullet fired without a chamber can still acheive enough velocity to do damage over short distances. So don’t try to make a bullet push out of its case, you might just win that Darwin Award after all.