You watch too much TV
The way the ammo is stored has a lot to do with it. When our house burned down in 97, I had an unopened case of 22 lr in my bedroom closet. When the rounds cooked off, the up facing rounds shot like out of a firearm. The shell had no where to go because it had the weight of the rest of the case behind it. They had enough velocity to permeate the metal roof of the house. I had pictures at one time of the sunlight shining through all of the holes, but it has been misplaced after 15 years. One firefighter said he hadn't heard a firefight like that since Vietnam. Ammunition in metal mags turned the mags into twisted pieces of metal. The rounds were were most concerned about were loaded in revolvers and other firearms. We lost 32 firearms in the fire, I don't know how much ammo and about 15 lbs of black powder. The explosions were heard from up to 15 miles away. All five members of my family are competitive shooters, so it was a disaster loosing the ammo and guns.
Ammo? You guys have ammo? Where can I get some?
First the guns were the problem. Now the ammo will get you too.
^This comment piqued my interest. I don't store powder in my safe, but I'd like to know if this is true or not anyway.
I think our resident chemist, SA Friday, should chime in here because I am having a hard time believing a gun safe will explode like a 500lb bomb if it has black powder in it. It was used in mining many moons ago, but a safe bomb?
High explosives (HE) used for blasting and bombs burn (change from solid to gas) with such intense heat and high rate of speed that they actually produce shock waves that propagate through and exert pressure on, any surrounding materials. A much faster rate of speed than black powder. To the best of my knowledge, HE classification has a minimum burn rate cutoff of around 3300fps and black powder unconfined is around 1300fps. For a point of reference, DET cord detonates from 7,000-8,000 fps.
Unlike smokeless powder that needs to be confined to produce high pressures, Black powder burns basically at the same rate of speed in a confined space or not according to SAAMI, but it still doesn't detonate.
Either way, unless the safe is FULL of black powder, I have a hard time believing a typical amount of black powder would produce enough pressure in a gun safe to make it a bomb. But I've been wrong many times before...
I looked at a couple of safes that were basically the same save for the fire rating. When I took apart the liner of both I noticed that the one with a fire rating had standard drywall panels lining the inside of it. So there's your answer for a cheap fire locker for your ammo. Whatever you store it in just line it with drywall and that will help increase the amount of fire/heat it can take and hopefully buy you some more time before the fire dept arrives to start putting out the blaze. Obviously if it takes too long and the drywall fails and they start cooking off you're in the same boat but that extra time bought may make all the difference between saving your home and watching it burn to the ground over bureaucratic (i.e. no basis) rules.
Thanks, Jer. Just what I was looking for. & I hope the drywall never gets tested...
Leo