max ambient temperature for ammo

[nbirnbaum2]

Quick question how hot is it ok to expose ammo/shotgun shells to for 4 or 5 hours. Im thinking about going to visit a friend in the desert. Expect 130-140 degrees in the trunk

[Cactus_Tim]

Just a quick Google yielded this: Maximum storage temperature for ammo?

Desert warfare temps of 120 deg. seem to have no loss of performance.

IIRC, When I worked in aerospace engineering we did some tests that showed nitro-cellulose based propellants began to degrade at about 225-250f.
I don't recall how many cycles between that and -60f we subjected it to but it was unaffected by -60f to +160f cycles.

[billped]

If it gets to be 300+ you have a problem. No, not Kelvin. ☺

Mythbusters tested it and could get ammo to cook off until 450.

[barrage]

I don't know exactly what temperature is a problem, but I can tell you from experience that a lose round of .40 S&W that I wasn't aware had been put in the bag of junk mail I take with me to the desert to burn lasted about 5 minutes in a campfire with some well established coals before it cooked off and hit someone in the leg...

So, it's going to have to be pretty hot. Much hotter than any ambient temperature is ever going to get.

[pacrat]

Increased ambient temp can and does effect burn rate of powders. Some ammo loaded close to max, that is subjected to high temp [100 f and over] at time of firing is prone to over pressure signs.

Factory ammo not an issue safety wise. But will also sometimes show flattened primers, expanded heads, etc

JM2c

[BigPimping]

I would guess above 450 farenheit.

[jkody]

Never had an issue with my spare loaded mags I keep in the truck for my CCW gun.

[CandG]

I think moisture is the bigger issue. Keep it dry (with desiccant if necessary) and you should be good at all temps that are short of igniting the powder.