Centerfire ammo needs a strong precise hit to the primer to set it off, I think that's statistically unlikely for a loose object like a screw or a zipper to set that off.
Rimfire ammo has the primer inside the rim of the base. I suppose it could be possible for a heavy tumble against a sharp metal ridge in the drum being enough to discharge the round.
Is it the heat or the percussion that sets them off? In the drier they would be bouncing around in a metal container.
Centerfire ammo needs a strong precise hit to the primer to set it off, I think that's statistically unlikely for a loose object like a screw or a zipper to set that off.
Rimfire ammo has the primer inside the rim of the base. I suppose it could be possible for a heavy tumble against a sharp metal ridge in the drum being enough to discharge the round.
Thanks, as you can tell Im not super well informed about firearms in general