How hot can ammo be safely stored?

[Gunny]

Most military ammunition is sealed where the bullet and brass meet and over the primer, which helps a lot on the humidity part. The way I understand it, powder starts to decay at a slow rate from the moment it's produced, vitals just outgas naturally and higher heat speeds up the outgassing. We did shoot up a lot of older powder in our 155mm howitzers, but it had been tested at specific intervals and was stored in bunkers with several feet of dirt covering them to keep the interiors cooler. That being said, I do have a pretty good stash of reloading powder stored in the house that I've had around for years and when I run across the need to use some of the old stuff, I always do the sniff test, but I've never discarded any and since I'm not a precision shooter, I can't see any difference in performance.
I don't think I'd take a chance if there was any possibility of the interior getting sustained temps of 100 degrees or more.

 

[Raspy]

I don't think I'd take a chance if there was any possibility of the interior getting sustained temps of 100 degrees or more.

Seems like 100 degrees is a very cautious number. Daytime temps can reach that regularly in lots of areas. I hope that isn't the practical high limit because I know I'll be over that.
As mentioned earlier, ammo temps in the sand box were way hotter.

 

[MossRoad]

Seems like 100 degrees is a very cautious number. Daytime temps can reach that regularly in lots of areas. I hope that isn't the practical high limit because I know I'll be over that.
As mentioned earlier, ammo temps in the sand box were way hotter.

Heck your body temp is 98.6.

 

[GaryM]

I've had a few of my hand loaded 9mm go through the washer and dryer. They were in a pants pocket and not noticed until they fell out and made noise in the dryer. So whatever the temp of an electric dryer running for 15 minutes or so will not set off CCI primers and Longshot powder.

Oh, they shot fine right afterwards too.

 

[Gunny]

Seems like 100 degrees is a very cautious number. Daytime temps can reach that regularly in lots of areas. I hope that isn't the practical high limit because I know I'll be over that.
As mentioned earlier, ammo temps in the sand box were way hotter.

Yessir, that was a typo, should have been 110 degrees sustained. And any differences in the ammo wouldn't be immediate, but long term as the conditions continue