Now I know for sure that I'm not going to be able to get the ammo if i initiate the bunker's self-destruct, but does the ammo in the footlocker respawn even when I've killed all the BoS members one at a time?
I actually wondered this myself, so I tested it.
The answer is: No. Once I had finished killing off the BOS, the ammo crate didn't respawn. Thats really how it should be though, the free ammo crate is sort of an exploit as it is.