Dallas PD car burns up. AR-15's ammo cooks off.

[surprise_i'm_armed]

http://www.wfaa.com/sharedcontent/dws/w ... 961b1.html" onclick="window.open(this.href);return false;

The above link contains a text story and a short video.

A 2004 Dodge Intrepid, Dallas PD cruiser, caught fire and the officers didn't have time to remove their
AR-15 from the trunk.

The ammo cooked off and luckily no one was hit by the result.

Dallas PD switched to Dodge Intrepids as part of their fleet after an officer was rear-ended in his Crown
Victoria while sitting on a US 75 construction site, and was burned to death.

Dallas PD has had a very questionable record with regards to maintaining their vehicles and making sure that
the oldest cars are used up first. The repair garage for DPD was examined some time ago by the Dallas Morning
News for its lack of promptness in repairing police vehicles in order to keep a minimum # of cars available for patrols.

Not that maintenance seems to be at fault at this incident. Just FYI.

SIA

[joe817]

Yes, it seems as though Dallas is having its problems with its patrol cars.

KXAS(the NBC affiliate in Ft.Worth) says even though the catalytic converter started the fire, the 200 or so rounds of ammo for their AR-15 in the trunk, cooked off and the resulting explosion kept firefighters at bay:

"Ammunition Explodes as Dallas Police Cruiser Burns"

Full story: http://www.nbcdfw.com/news/local/Ammuni ... rns--.html" onclick="window.open(this.href);return false;

[particle]

Out of curiosity, what usually happens to ammunition when it burns in a fire? Does the brass casing explode? Does the bullet fly out of the casing just like if it were in a gun? Does the brass fly backwards, and the bullet fly forward? Does the bullet have enough energy to actually pose a serious threat if you're struck by it (assuming it makes it through the metal surrounding the trunk)?

When I was a kid, I taped an arrow to the back of a shotgun shell and shot the contraption at a wooden crate (guess I'd seen too many episodes of Duke's of Hazzard, and Rambo). The shell exploded, but the massive, gaping hole in the wood was simply not to be. So, I upped the risk (in hopes of greater reward), and taped a .270 rifle round to the arrow. I cowered behind a tree, leaned over and fired my (15 lb. draw) ancient weapon at the crate, then quickly ducked back behind the tree. Well, needless to say, that was the first and last time I tried that. Shrapnel (and a 30" wooden toothpick) came flying straight back at me... Had I not been standing behind the tree, I would have been having a really bad day... That being said, the bullets were forced against the wood with insufficient force to penetrate, but enough to send the arrow and casing backwards. Under normal circumstances, you're simply dealing with a cardboard box and maybe a little plastic, or a metal magazine putting equal resistance on either end of the round of ammunition.

So, what usually happens when ammunition explodes like what happened in the Dallas PD car?

[Bart]

So, what usually happens when ammunition explodes like what happened in the Dallas PD car?

For bullets that aren't chambered, the bullet and brass separate when the gunpowder burns/explodes. The brass may split or burst depending on pressure. The pieces spread apart according to the laws of physics, so the (lighter) brass goes faster and further than the (heavier) bullets. It can put out an eye.

[A-R]

The Discovery Channel show "Mythbusters" has tested the heated exploding ammo phenomenon a few times. If unchambered, the brass and bullet separate and it's the brass that moves fastest and is most dangerous (though likely not lethal). But if a round is chambered, it's the same effect as pulling the trigger - bullet sent hurtling down the rifled barrel (very lethal, of course).

My question is, would an auto-feeding weapon such as the AR-15 actually cycle and load a new round that could then also be fired down the barrel? Probably not likely as once one bullet "explodes" they would all explode fairly quickly. But it could be possible if the chambered round explodes first, cycles the action, loads another round that then also explodes, repeat ... Perhaps the round in the chamber is more exposed to excess heat (as the receiver itself heats up, possibly faster than the magazine ... especially if it's a composit P-MAG?????).

[USA1]

good thinkin , that should be on the show

i would like to see that put to the test

[surprise_i'm_armed]

austinrealtor:

Does an AR-15 have a thumb-type safety? If so, and if the safety was engaged,
it seems that possibly the round in the pipe would hurtle down the barrel, but the
rest of the rounds in the magazine would not cycle.

Sound logical?

SIA

[FlynJay]

austinrealtor:

Does an AR-15 have a thumb-type safety? If so, and if the safety was engaged,
it seems that possibly the round in the pipe would hurtle down the barrel, but the
rest of the rounds in the magazine would not cycle.

Sound logical?

SIA

Not really, the safety only prevents the trigger mechanism from dropping the hammer. so the bolt would cycle. But if the barrel is hot enough to cook off a round, I would bet the case would be stuck in the chamber.

[Liberty]

austinrealtor:

Does an AR-15 have a thumb-type safety? If so, and if the safety was engaged,
it seems that possibly the round in the pipe would hurtle down the barrel, but the
rest of the rounds in the magazine would not cycle.

Sound logical?

SIA

Not really, the safety only prevents the trigger mechanism from dropping the hammer. so the bolt would cycle. But if the barrel is hot enough to cook off a round, I would bet the case would be stuck in the chamber.

A fire would likely cook off the rounds in the magazine before the barrel and chamber got hot enough to bake off.

[MoJo]

What's more dangerous in a fire than ammunition is your common 4th of July fireworks. They are made with blackpowder that is an explosive rather than a propellant. I have seen the results of fires both in ammo storage and fireworks stands. Give me the ammo any day! Providing of course there's no artillery ammo involved.