CFC Firearms, Ballistics & Tool Mark Examination Flashcards

What does the term 'rifling' refer to in the context of firearm evidence?

Answer: Spiral grooves cut inside a barrel that impart spin to a bullet

Rifling consists of helical grooves machined into a firearm barrel that cause the bullet to spin, improving accuracy and leaving unique striations on fired bullets.

In ballistics examination, 'lands and grooves' on a recovered bullet are used to:

Answer: Link the bullet to a specific firearm barrel

Land and groove impressions on a bullet are produced by the rifling of a specific barrel and can be microscopically compared to test-fire bullets from a suspect weapon.

Which technique do firearm examiners use to compare striations on two bullets under simultaneous magnification?

Answer: Comparison microscopy

The comparison microscope allows an examiner to view two bullets or cartridge cases side by side simultaneously, enabling direct striation alignment comparison.

Gunshot residue (GSR) analysis is used to detect the presence of which elements commonly found in primer residue?

Answer: Lead, barium, and antimony

Traditional GSR analysis (via SEM-EDX) identifies characteristic particles containing lead, barium, and antimony originating from primer ignition.

A fired cartridge case found at a crime scene can be linked to a specific firearm through marks left by the:

Answer: Firing pin, breechface, and ejector

The firing pin impression, breechface marks, and ejector/extractor marks on a cartridge case are compared microscopically to test-fired cases from the suspect weapon.

What is the term for the unique microscopic surface characteristics on a tool that are transferred to the material it contacts, used in tool mark analysis?

Answer: Individual characteristics

Individual characteristics are random, microscopic imperfections on a tool's surface that uniquely distinguish it from all other tools of the same class.