How hot does ammo have to be to cook off? I want to a firearm in the car but am worried about 100 degree heat where car temps can be in the 140's. Oh, and will heat damage a 1911 at all?

car heat isn't going to cook it off.  I keep firearms in all of my vehicles all the time.

Quoted: car heat isn't going to cook it off.  I keep firearms in all of my vehicles all the time.

So do I.  I also keep a few loaded 1911 mags a box of .38 Special FMJ and two boxes of .45 acp Cor-bon.  I have been doing this for years here in AZ where it is not abnormal for summer temperatures to hover around 117 to 120 degrees in the shade.

I've even gone to my truck and my gun was so hot it could not be comfortably held in my bare hand.

No cook offs.

I figured as much but wanted to be sure. Thanks.

About 10 years ago, we had a dentist wreck his car on a major highway in our fire district. Car caught fire with him in it. He was already dead from the accident.  When we rolled up, we started hearing gun fire. Everyone on the engine company hit the deck. SHP drew their guns and dove behind their cars.

After about 5 or 6 rounds, it was over.  Turns out the guy had an AR in the back seat with a loaded mag and a round in the chamber. First round cooked off from the heat of the fire. Semi-auto AR wonderful gun that it is reloaded and fired a couple more rounds until the recoil turned the rifle around in the seat and part of the spring from the melted seat caught the bolt on its way back.  I guess it would have fired the whole mag if that hadn't happened.

I don't think you will have to worry about cookoff just from weather conditions.  

I can tell you this, if ammo does not "cook off" here in Phoenix in the summer, it never will. I store a loaded 45 or 9mm in my car every day. Sometimes the temperature in Phoenix will reach 118 degrees. I have never heard of ammo discharging here so I doubt anyone else has to worry about it.

Ammo in all of my vehicles for 20+ years (NO, not the same ammo! ), frequent triple-digit-days here in the Summer, never a problem...


Down here, you do have to worry rust on your weapons, mags, etc.  (high humidity) - frequent cleaning (if not rotation) is SOP.

In a vehicle tactics class we had loose ammo cook off in a car.  In all fairness the car was on fire at the time and had been rolling for a good 5 minutes before we heared the first pop.

Seriously, if ammo doesn't cook off in your gun after you fired a 50 round string in under a minute, how's it gonna cook off in even the hottest of cars (that are not engulfed in flame)?

Our Troops in Iraq don't have any problems with rounds exploding due to heat, tanks don't have A/C.