I watched some video (after watching a movie with the fire setting off the ammo and the bullets “shooting” all over the place) about what really happens with ammo during a fire.
It just does a lot of popping but no velocity. It was some fire department doing training. Then another one was a demonstration. The wooden building mock-up contained the small explosions as the rounds popped off.
But yes - the kitchen would probably need some work done on it. The small explosions would probably be enough to blow the door open.
I would think that without the barrel to enclose the gas pressure and direct the bullet in a single direction for a few critical microseconds, the bullets would just explode without becoming ballistic projectiles. But I don’t know, I’ve never set a bunch of them on fire and waited. It’s not that I’m not stupid enough, I just never got around to it.
That sounds like the video SAAMI made when evaluating the risk to firefighters in the event of a fire in an ammunition warehouse.
https://saami.org/publications-advisories/sporting-ammunition-and-the-firefighter/
About the Results
The video shows that sporting ammunition outside a firearm:
1. is unlikely to ignite under extreme conditions of impact,
2. will not propagate in a chain reaction from one cartridge or shell to another,
3. does not mass explode, and
4. may be controlled by fire fighters using water and wearing standard
structural fire fighter protective clothing and self-contained breathing apparatus.
You would think that the lighter cartridge cases would fly while the much heavier bullet would remain relatively stationary, given Newtons Laws.
I can tell you that an M79 grenade will explode twice in a fire. First the propellant charge and then later the grenade itself. My old neighbors actually did this. Found an M79 grenade in the Utah desert and then put it in their campfire. They lived.