Link to mod: https://mods.factorio.com/mod/unlimited-ammo

This mod sets value "consumption_modifier" to zero, to prevent ammo usage in weapons. (Yes it's cheaty. I like having to expand without having to deal with too much resource loss to incoming waves.)

When dropping bombs from the B-17 (other craft not tested, but most likely affected, since I'd assume you use a common code library), this causes the game to freeze and enter a memory leak loop, which does not seem to have an end - it'll last until either Factorio crashes/is closed or the PC crashes.