CFC CFC Firearms, Ballistics & Tool Mark Examination 2 — Questions and Answers
Question 1: In a shooting incident reconstruction, 'trajectory analysis' is used to determine:
- The chemical composition of the bullet
- The path the bullet traveled and the relative position of shooter and victim (Correct answer)
- Whether the firearm was legally registered
- The caliber of the weapon used
Correct answer: The path the bullet traveled and the relative position of shooter and victim
Trajectory analysis uses bullet holes, rod or laser alignment, and wound track data to reconstruct the bullet's path and infer the shooter's approximate location.
Question 2: Which characteristic of a bullet wound indicates that it is an exit wound rather than an entry wound?
- Circular, punched-out margin with abrasion ring
- Larger, irregular, and stellate margin without an abrasion collar (Correct answer)
- Presence of soot and stippling around the wound
- Small round defect with inverted edges
Correct answer: Larger, irregular, and stellate margin without an abrasion collar
Exit wounds are typically larger and more irregular than entry wounds because the bullet destabilizes and pushes tissue outward, leaving a ragged, stellate margin without an abrasion collar.
Question 3: Which type of evidence is a 'fired projectile' classified as in forensic ballistics?
- Class evidence only
- Individualized physical evidence (Correct answer)
- Pattern evidence
- Trace evidence only
Correct answer: Individualized physical evidence
A fired projectile bearing land and groove striations can be individualized to a specific firearm barrel, making it individualized physical evidence.
Question 4: Serial number restoration on a firearm from which the serial number has been ground off uses which forensic technique?
- Infrared spectroscopy
- Chemical etching or magnetic particle inspection exploiting subsurface metal stress (Correct answer)
- X-ray diffraction
- Ultraviolet fluorescence only
Correct answer: Chemical etching or magnetic particle inspection exploiting subsurface metal stress
Grinding compresses but does not fully erase the altered crystal structure beneath; acid etching or magnetic inspection reveals these subsurface stress patterns, restoring the number.
Question 5: The National Integrated Ballistic Information Network (NIBIN) is a database that allows law enforcement to link crimes by comparing:
- DNA profiles from gun handles
- Digital images of fired cartridge case marks (Correct answer)
- Fingerprints on ammunition
- Ballistic trajectory calculations
Correct answer: Digital images of fired cartridge case marks
NIBIN stores and compares digital images of breechface, firing pin, and ejector marks from fired cartridge cases to link shootings to a common weapon across jurisdictions.
Question 6: A forensic consultant is asked to determine the distance from which a shot was fired. The primary evidence used is:
- The caliber of the recovered bullet
- The pattern and density of soot, stippling, and powder residue around the entry wound (Correct answer)
- The victim's toxicology report
- The type of firearm recovered
Correct answer: The pattern and density of soot, stippling, and powder residue around the entry wound
Shot distance is estimated by examining the pattern of soot (contact/close range), stippling (intermediate range), and absence of both (distant range) around the entry wound.
CFC CFC Firearms, Ballistics & Tool Mark Examination 2
In a shooting incident reconstruction, 'trajectory analysis' is used to determine: