Lots of shooters are curious as to what happens when a cartridge detonates outside a handgun; I found out.
I use a tumbler brass cleaner and dry the brass in the oven at 300F for 2-hours. Occasionally I will find a loaded cartridge lying among the brass before drying, but on rare occasion, afterwards. Yesterday I was drying several hundred rounds of .45ACP brass on a 9"x14" cookie sheet in the oven when I hurt a loud "pop" that sounded like a Lady Finger going off. Never heard that sound before in the house, so I instinctively knew what it was.
Upon checking the oven I saw 30-40 pieces of brass lying underneath the cookie sheet. The ruptured case was still on the cookie sheet with the 230gr lead RN bullet laying immediately in front of it, so there was no danger of it exiting the oven. The primer had backed out of the casing and I did not find it, so I am guessing it was the powder (Unique) that overheated and burned. The pressure generated by the burning powder caused the case to aggressively fail.
I'll have to do a better job of inspecting my brass before cleaning, and I will cut the heat to 275F.