What does the term "striations" refer to in firearms examination?

The term "striations" refers specifically to the scratches or fine lines that are created on a bullet as it travels through the barrel of a firearm. These striations are a result of the unique features of the barrel, particularly the lands and grooves that impart distinctive markings on the bullet. Each firearm has a particular pattern of rifling, and when a bullet is fired, it engages with these lands and grooves, leaving behind characteristic scratches that can be matched to a specific gun.

This information is crucial in firearms examination because striations help forensic experts link a bullet recovered from a crime scene back to a specific weapon, aiding in criminal investigations. By comparing the striations on the bullet with those produced by suspect firearms, investigators can determine the likelihood that a particular gun was used in the crime.

The other options pertain to different aspects of firearms analysis. Indentations from the firing pin relate to the imprint left on the primer of a cartridge, which is a separate area of study. Residue left on a bullet after firing generally refers to firearm discharge residues but does not specifically describe the visual marks left on the bullet's surface. The shape of the bullet's tip concerns its design and performance characteristics rather than the unique markings created during its travel