A toolmark that occurs in a semiautomatic pistol when there is a cartridge at the top of the magazine and the slide is retracted. The lug on the underside of the slide drags across the 12 o’clock position on the cartridge case leaving a striated mark. This mark cannot occur when a cartridge is manually inserted in the chamber and the slide is released or to the first cartridge when a loaded magazine is inserted in the firearm with the slide locked back.
1