Bullets discharging from heat

[Mr.RoDiN]

At what temp would a a 9mm bullet discharge? We go out to the desert to shoot with my buddies. Sometimes it can get up to over 110 out there, during the summer. My concern is, sometimes our ammo cans get so hot, if placed under the sun, that I get scared of a bullet dischargin. Does anyone know the aproximate temprature where it can be dangerous?

[762cavalier]

don't Know what the exact temperature is but sunlight (even direct desert sunlight) will not get close enough to cook of any of the rounds. And if it were unless the round was in a tight confined space like the barrel of a gun then it will just pop the brass or push the bullet out. No bang with bullets flying like in the movies.

[ViPER395]

The sun even in a hot car will not cook off ammo.

Like 762 says, and I speak from experience, even if they did cook off, they wouldn't even exit your ammo can.

[DesertDawg]

My brother-in-law was a fire department engineer, and I'm pretty sure that he said that the temp would have to be more than 400 degrees for ammo to "cook off" (I don't recall the exact temp he said).

What I do know is that I've been shooting in the desert for 35+ years, and have yet to have any ammo "cook off" inside of a steel ammo can. The only ammo that has "cooked off" when I was in the desert were some rounds that some jerk had thrown into a fire pit.
I guess that it was partially my fault, for not removing the ash and charcoal before starting a campfire.

Bottom line: Heat is NOT good for ammo, which is why it is highly advised to store it in a cool, dry location. It would be better to slide those ammo cans under some shade, and open the lids so that the ammo is at the same temp as the air.

[westcoastr]

i can't find the reference but the 400 deg mark is what i remember - as said before, primers a powder are designed to not ignite on a fresh round in a blazing hot chamber

[Two Shots]

Found this info, don't know how exact it is.

In his book "Gunshot Wounds" Vincent Di Maio describes various experiments where ammunition was heated in ovens. He says that .22 long rifle cartridges detonate at an average of 275F, .38 Special at 290F and 12 gauge shotgun shells at 387F. The interesting thing about these furnace experiments was that in all instances the cartridge cases ruptured, but the primers did not detonate. In fact the primers were removed from some of the ruptured cases, reloaded into other brass and fired.

[Beelzy]

I would worry more about powder deterioration from the extreme heat.

Reloaders rule #1

Keep all powder stored in a cool dry place. Even when loaded in a cartridge.

[What Just Happened?]

Well, the primer is what supplies the heat for the gun powder to ignite and the primer does not require any heat to create that heat. The primer only needs to have its materials mixed (what happens when the primer is struck by a firing pin). Extreme heat may cause the stuff in the primer to flow together, but it seems that the gunpowder will ignite before you get primer flow.

I'm just amazed that the ignition of the gunpowder didn't render the primer useless.

[Bruce3]

i remember there was a mythbusters episode where they baked bullets in an oven, i think they concluded that a bullet that is not chambered in a gun can't cause serious harm.

[ViPER395]

22LR will break through the glass of a fireplace door. Trust me.

[brando]

The only time I've ever seen cook-offs was a burning HMMWV. Even in the brutal heat of the Middle East, I never saw a cookoff from just exposure to the environment.

[Rangerat]

Some powders are temperature sensitive. Some increase pressure with temperature and some decrease. My only concern would be if you are loading hot and you have a powder that increases pressure as temperature increases.

[Chaingun]

My guess is 451 deg

[ar15barrels]

22LR will break through the glass of a fireplace door. Trust me.

I wanna hear this story...

[ViPER395]

Roger that.

It was in the 80's. My parents had a fireplace with one of those glass doors. The ones that, like, have two long vertical panes on each side, and fold to the side so you can light a fire, add wood etc. So I guess there was one or a couple live 22s on the rug, or someplace, and of course, since everything that my mom considers trash goes into the fireplace, well, you know where those 22s ended up.

So some time later, and not the same day, we had a fire going. We often left our fire unattended with the glass doors shut when we were outside. My parents always kept me (and them) busy raking leaves, mowing, etc.

So upon our return to the house we find glass all over the hearth, and my great-grandma who lived with us said she heard a loud pop when she was in her room.

We found the case outside the fireplace.

Our guess was that when the fire's heat ignited the primer/powder, the lead stayed put in the fireplace and the shell is what broke the glass. It seems like it was really thin glass anyways. Not as thick as my wood stove glass by any means.

I wanna hear this story...