After I finish shooting I usually burn any left over boxes, target paper etc. So, I light the two "empty" silver bear boxes with the paper stuffed in them and just stand there. To my surprise there is a loud bang. I guess I did not free the shell up from the paper but instead put it and the paper into the fire. Here are some pictures. I guess the primer went off and set the cartridge off. Glad nothing hit me. So, if anybody tells you a cartridge will not go off in a fire that is patently not true. They can and will explode if that primer goes off. Another lesson in being careful.