Thanks for the illustration of the point and so sorry for your loss.
First hand experience is also the best to learn from. Time heals all wounds... But yeah, it still stings. I had some classic old powders, bullets hand polished by my grandpa in 1981, lots of his notes, etc.
This particular fire was in a well insulated metal building. The fire inspector said the temps were in excess of 2000°F.
Unloaded primers do go off in a fire. The FD was there already and we told em to let it burn. There was no saving anything. As the fire moved westward, it exploded one of the oxy-acetylene torch tanks, then about 15k primers went off in about 3 seconds. It sounded like no other bundle of black cat firecrackers on earth.
Nearby, I had about 40 pounds of powder inside a mini-fridge. None of it exploded like a bomb, but instead just burned. That corner of the shop was actually the "least" damaged. Though that's not saying much. When we told the FD about the powder and ammo, they were only concerned about it being black powder. I had only one pound of BP and they were not worried. They just stayed a bit farther back.
The unloaded projectile stockpile ended as a puddle of lead full of hollow copper cones, in the bottom of a toolbox.
In one of my pictures above im holding a copper jacket from a 44mag. The lead all melted out.
One last point I realized, and would like to make is that without a barrel or a bolt behind the cartridge, half the energy will be released in a rearward direction. This means low velocity. In addition to this, the bullet has no barrel to spin or guide it, resulting in instant keyholing. Again lowering velocity. The casing itself will also expand, and possibly rupture, again lowering velocity, or even rendering the cartridge inert.