Large quantities of black powder ammunition in fire

There are all sorts of YouTube videos demonstrating the safety of modern smokeless powder ammunition in fire, impact and crushing accidents, but what about black powder ammo? If you had say, a .50 BMG ammo can full of .50-70 Government, black powder-filled cartridges and you had a house fire, would there be a risk of an explosion? My local volunteer firemen are a pretty good bunch of guys and I wouldn’t want anything bad to happen to them. Thanks. Bill.

A single ammo can of 50-70 is no big deal.

Edit to add:

BP and SP cartridges inside of a 50cal ammo can will act the same. The can should contain all of the projectiles.

Bulk powders, Federal limits on BP are more restrictive. It’s 2-3x allowable limit for smokeless over BP.

Smokeless powder, with nothing to contain pressure, will simply burn, and pretty slowly at that relative to …
Black powder which goes up extremely fast in a bit flash of smoke and fire.

Edit2: I read this years ago
"During my very long EOD career I have burned about two billion rounds of small arms ammunition. When burned in an open pit, the bullets and fragments of the case seldom travel more than about 15 feet when the round goes off.

Small arms ammo does not mass detonate when burned in a can or otherwise. When burned in an ammo can, the can gets dented from the bullets and that is it. When linked ammo is burned in a military ammo can one can see where every bullet made a dent or small hole in the side of the can. Never saw a bullet penetrate the can or blow the can open."

BP and progressive burning propellants when burned in open uncontained pits and NOT contained within a vessel or container that is capable of containing and causing an increase in pressure are relatively benign. Hot and rapid burn!! But, This will be a low pressure deflagration. Only a few smokeless powders are capable of achieving a DETONATION burn rate. and that depends on ignition source and shape and strength of the containment vessel and other factors. Propellants burn, unless the burn rate can be made to go super, super sonic, 1000 meters /second or greater, and create a shock wave within the compound(achieving detonation) The material will burn itself out(slowly compared to high explosive compounds). Seal and pack BP in a substantial container you have a problem. Powder magazines for home storage are wood lined or all wood and well vented. At the shop I work at we have a 2 ton smokeless magazine that is designed to rupture at very low pressure. Our BP magazine is limited to 100 # and is also well vented and designed to rupture at very low pressure. A house full of natural gas that ignites may only achieve 100 PSI but the volume and low strength of the container(house) will create a significant amount of damage but not the shattering , fragmentation of a high explosive detonation. I store all my reloading powders outside now in a locked shed. Containers of Gas and other solvents are far more volatile than ammo and reloading components

Hi Jesse, It’s an interesting video, but every single cartridge in it was a smokeless powder cartridge. My hypothetical scenario involves a .metal ammo can completely filled with large caliber (.50-70,) black powder cartridges in close contact with each other. Will black powder cartridges chain detonate in a confined space in a fire? Historically, many arsenals and black powder ammunition factories have exploded. During the Civil War, an explosion here in Pittsburgh killed hundreds of women and child workers who were hand filling and tying paper cartridges. Even today, a third world fireworks factory blows up somewhere every few months. This could make a good homemade “Mythbusters” style video if someone lived in a desert out in the middle of nowhere.

I talked to another EOD guy and he said no, you don’t need to worry about a can of black powder rounds.

“The main takeaway on the ammo is that there is no mass detonation or fragmentation on small arms, whether it is in a can out outside. I’ve got a .50 can from a fire that is bulged and dented, a couple of small tears. No real difference from the materials in the SAAMI video. BP does not detonate, and the burning rate would be reduced by the cartridge cases, so while it might contribute to a fire in large enough quantities of 45-70 I would still expect any explosive threat to be minimal.”

A mythbusters type video would be fantastic!

Fireworks factories also have flash powder, which is MUCH worse and treated as such by the BATFE, and we know how safe 3rd world factories are :) Static is #1 concern with flash (and other explosives). Large strong barrels of black powder do have a large amount of stored energy. 50-70 cartridges, not so much.

pressure is relieved so quickly when the cartridge case ruptures , The case being loose and unsupported. The cartridge case itself is lighter than the projectile and more often than not the projectile will remain near the point where the ignition took place and the case and primer are a few yards away. I have picked primers out of flesh on a couple of Marines that were right next to a fire (mine and an AMtrak)that belted MG ammo was burned. The cans/containers for bulk powders are designed to rupture at low pressure. there is a significant difference between Deflagration and detonation. Unless the cartridges, BP or smokeless are contained in a tight fitting container such as a firearm chamber, they will “pop” and burn. A firearm with loaded chambers in a fire will send the round out just like it had been fired normally. Mythbusters did do an experiment with various gases attempting to propagate a detonation…