Storing ammo, security cabinet or fire safe ?


January 6, 2006, 06:28 PM
Hi folks ! I've been browsing this forum for awhile and this seems to be a nice place. I'd like your opinions on safely storing ammo. I had been keeping mine in a medium size fire safe but I was told by someone on another forum that in the event of a fire the ammo would actually explode inside the safe.

I can understand the contents might "cook off" in a series of small bangs as bullets and casings seperate but, explode in one big kaboom? :what:

I thought the thicker steel of the fire safe would make for a better choice.

Your opinions please.

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January 6, 2006, 06:40 PM
A safe is overkil in any event. If your going to drop the dollars on a thick steel walled safe then using it as ammo storage is underutilizing its intrinsic value.

By a cabinet that locks and store your ammo there. There are several good cabinets out there that serve the purpose well.

The explode part is most like from storing powder. If you have powder to store then never store it in a container that holds pressure. Most powder storage cabinets have pressure relief valves built in. The reason is that as pressure increases the burn rates increase and it is a viscous cycle that ends in a kaboom. If the gasses of combustion can vent then it is just a deflagration not a detonation.

Ammo would probably have the same tendencies if stored in a sealed vessel and the pressure allowed to rise significantly. However, gunsafes usually have a fire seal that expands with heat. The rise in pressure would most likely blow past that seal way before the safe could overpressure enough to sympathetically detonate the safes entire ammo contents.


January 6, 2006, 07:10 PM
i store my ammo in green 'case-gard' boxes in the garage, on a shelf.
i am far more concerned about the gas cans for the snowblower and lawnmower than i am about a few thousand rounds of ammo...

January 6, 2006, 07:56 PM
Most of mine is in cardboard boxes and rubber bins. A great deal of it is under the bed. I ran out of room in the closet after 40 years. Oh, and there're ammo cans piled up here and there.

I keep the guns locked up, not the ammo. I can't imagine a smash-and-grabber running off down the street with cases of ammo on each shoulder. I wonder if I'd miss one or two cases of ammo?

"Is anything missing?" Duh, I dunno.


P.S. - Come to think of it, the gun stores I've been in leave theirs out on the shelf at night.

January 6, 2006, 08:08 PM
Ammo cooking off in a tightly sealed container is sort of like a super sized pipe bomb.

So you do not want super strong containers that will hold in a lot of pressure.

Ammo cans from the military bend and flex as pressure builds and they lose their seal with the lid gasket, so pressure is vented long before any sort of "bomb" pressure would be reached.

Most safes have holes in them for golden rods or to bolt the safe to the floor or even the door may not be that well sealed.

Some of the super serious safes that are actually rated for jewelry stores and what not can seal up super tight and these are not good for ammo storage.

This is all info I have learned form volunteer firefighters on this and other boards when ammo storage comes up to be discussed.

Overall the only ammo I keep in an actual safe is some loaded magazines for guns kept in that safe. This is not enough ammo to pressurize the whole safe and my safe has holes in it anyway and the door does not seal that tightly either.

The cabinet preacherman uses for ammo storage is similar to some smaller lockers I have for ammo storage. It is thin metal and will easily flex if there is more pressure than the door gaps can allow to escape. Having the ammo in a light metal container helps contain cooking off ammo that has bullets and brass popping around a bit like firecrackers.

These days I store enough ammo around I stack it in cases and don't worry about it since ammo cooking off is not that big a deal in my opinion.

January 6, 2006, 10:56 PM
Biere, great answer!

The main thing to remember about smokeless propellants is that they burn - they don't explode. Thus, if you keep them in containers that will vent the gas build-up, there should be no explosion hazard. I use Army surplus ammo cans because they're designed to do just that - vent gases in the event of a fire, so that the gas doesn't build up in them to explosive pressures.

(IMPORTANT WARNING: The above statement does not apply to blackpowder. That's a true explosive, and needs much more careful storage (preferably out of the house altogether!). It's often against local fire regulations to store more than a minimal quantity on-site.)

I built an ammo storage locker out of a steel office cupboard, with reinforced shelving inside it. This holds my ammo, which is either in factory packaging, or in .50-caliber ammo cans. In the event of a fire, neither the cupboard or the cans will be an explosion hazard. The process of building the locker was described in this thread (, and I've attached a picture below to illustrate it.

A fire safe might be counter-productive. It won't stop the ammo inside getting very hot, which might heat some of the primers to detonation level. This would rapidly and drastically increase pressures, as a chain reaction is not unlikely - and a fire safe is NOT designed to release pressure quickly! I'm not saying the entire safe would explode, but there's an increased risk of pressure rupture with such a "container" if it's full of ammo. I'd prefer to use the safe for (unloaded) firearms, and put the ammo somewhere else.

M2 Carbine
January 6, 2006, 11:46 PM
About ten years ago my gun shop burned to the ground. About 23,000 rounds of ammo, cans of gun powder, thousands of primers and most everything else gun related that you can think of. It was very interesting.

All things considered, IMO the best way to store ammo is in mitilary 50 cal ammo cans.

Even when some of the ammo cooks off it doesn't blow up the rest of the ammo in the can.
This can was full of 9mm and was about 15 feet from the fire. About a box exploded blowing a fist size hole in the can but I later shot the rest of the ammo.

January 7, 2006, 12:20 AM
Thanks a lot guys ! I'm going with the security cabinet for my ammo. The fire safe I have is an older one I bought from Staples office supply. I had previously used it for document storage but that stuff is all off site in a safety deposit box now. It's not a "Super Strong" safe but I'm not gonna take chances.

Besides the cabinet holds about ten times as much :D . Now I'm gonna fill it up ! I dont have as much as Preacherman (Nice cabinet BTW !) I saw the empty pics when I was looking for information on this subject.

Thanks again ! Dennis

January 7, 2006, 01:20 AM
Another vote for mil ammo cans. I bought many many of them over the years and store pretty much exclusively in them. I especially like it being modular so I can move and sort by cans and not cases or small boxes. Also they are fairly water resistant as a plus...

Highland Ranger
January 7, 2006, 09:59 AM
If the fire safe is a document safe, remember that those things have water impregnated in the insulation. Good for papers in a fire, bad for guns and ammo . . . .

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