Forensic Ballistics Review Questions 1
1. In forensic ballistics, what is the term for the raised area between the grooves inside a firearm's barrel?
A. Caliber
B. Land
C. Rifling
D. Smoothbore
Answer: B
Lands are the raised portions between grooves inside a rifled barrel.
2. Which term refers to the internal diameter of a firearm's barrel, typically measured between opposing lands, or the diameter of the ammunition designed for it?
A. Caliber
B. Land
C. Rifling
D. Smoothbore
Answer: A
Caliber refers to the bore diameter (commonly measured between opposing lands) or the cartridge/bullet size.
3. During a forensic investigation, a ballistics expert examines a fired bullet and notices distinct impressions left by the raised ridges inside the gun barrel. What are these specific raised helical structures called?
A. Caliber
B. Land
C. Rifling
D. Smoothbore
Answer: B
The raised helical ridges that impress the bullet are called lands.
4. What is the name for the overall system of spiral grooves and ridges machined into the interior of a firearm barrel to impart a stabilizing spin on a bullet?
A. Caliber
B. Land
C. Rifling
D. Smoothbore
Answer: C
Rifling is the overall system of spiral lands and grooves that spins the bullet.
5. Which type of firearm design features a completely flat, ungrooved interior barrel surface that does not impart a spin on the projectile?
A. Caliber
B. Land
C. Rifling
D. Smoothbore
Answer: D
A smoothbore barrel lacks rifling and does not impart spin.
6. During a forensic examination of a fired cartridge case recovered from a crime scene, the ballistician observes a distinct toolmark on the rim or the groove of the casing. This mark is left when the mechanical claw of the firearm pulls the spent shell out of the breech chamber after firing. Which of the following marks is being described?
A. Firing Pin Mark
B. Extractor Mark
C. Ejector Mark
D. Shearing Mark
Answer: B
Extractor marks are produced when the extractor pulls the cartridge case from the chamber.
7. A suspect weapon is test-fired in a laboratory. Upon examining the base of the fired cartridge case, the examiner notes a deep indentation directly in the center of the primer cup, caused by the strike that ignited the priming mixture. What type of mark is this?
A. Firing Pin Mark
B. Extractor Mark
C. Ejector Mark
D. Shearing Mark
Answer: A
The indentation in the primer caused by the firing pin is a firing pin impression/mark.
8. In a homicide investigation, a spent cartridge case is found with a clear, localized scuff mark on the rear face of the head, typically located opposite the extractor mark. This mark is created when the cartridge is pushed forward and flipped out of the firearm's ejection port by a protruding metal component. This is known as a/an:
A. Firing Pin Mark
B. Extractor Mark
C. Ejector Mark
D. Shearing Mark
Answer: C
Ejector marks are made when the ejector strikes the case and expels it from the firearm.
9. While examining a cartridge case fired from a semi-automatic pistol, a forensic ballistics expert notices a shaved or striated mark on the primer. This happens when the firing pin protrudes from the breech face as the barrel drops down during the unlocking cycle, causing the metal to scrape. This specialized toolmark is called a:
A. Firing Pin Mark
B. Extractor Mark
C. Ejector Mark
D. Shearing Mark
Answer: D
Primer shearing marks are striated marks caused during unlocking as metal is scraped around the firing pin aperture.
10. Which of the following marks on a cartridge case is primarily produced by the rearward motion of the casing pushing against the ejector block or pin, effectively forcing the empty shell to spin out of the gun?
A. Firing Pin Mark
B. Extractor Mark
C. Ejector Mark
D. Shearing Mark
Answer: C
11. Which part of a cartridge contains the projectile?
A. Primer
B. Bullet
C. Powder
D. Rim
Answer: B. The bullet is the projectile that leaves the barrel and travels toward the target.
12. Which part of the ammunition ignites the propellant when struck by the firing pin?
A. Case
B. Bullet
C. Primer
D. Rim
Answer: C. The primer contains a shock-sensitive compound that ignites when struck by the firing pin, which in turn ignites the propellant.
13. What part of the cartridge holds all the other components together?
A. Case
B. Primer
C. Bullet
D. Powder
Answer: A. The case (or cartridge case) contains the primer, propellant, and bullet, holding them together as a complete cartridge.
14. Which component produces the expanding gases that propel the bullet?
A. Primer
B. Rim
C. Propellant powder
D. Bullet jacket
Answer: C. The burning propellant powder generates high-pressure gases that drive the bullet down the barrel.
15. In centerfire ammunition, the primer is located at the:
A. Tip of the bullet
B. Side of the case
C. Center of the base
D. Neck of the case
Answer: C. In centerfire cartridges, the primer is seated in the center of the cartridge base (head).
16. Which part of a cartridge travels through the barrel toward the target?
A. Case
B. Primer
C. Bullet
D. Powder
Answer: C. Only the bullet exits the barrel; the case remains in the firearm.
17. The groove near the base of a cartridge case is primarily used for:
A. Holding the primer
B. Bullet expansion
C. Extraction by the extractor
D. Igniting the powder
Answer: C. The extractor groove allows the firearm's extractor to grip and remove the spent cartridge case from the chamber.
18. The neck of a bottleneck cartridge case serves to:
A. Hold the bullet securely
B. Contain the primer
C. Catch the extractor
D. Increase recoil
Answer: A. The neck grips the bullet firmly to keep it properly seated before firing.
19. Which sequence correctly describes the firing process of a cartridge?
A. Powder → Primer → Bullet
B. Primer → Powder → Bullet
C. Bullet → Primer → Powder
D. Bullet → Powder → Primer
Answer: B. The firing pin strikes the primer, which ignites the powder, producing gases that propel the bullet.
20. Which part of the cartridge case supports the primer in centerfire ammunition?
A. Mouth
B. Neck
C. Head
D. Shoulder
Answer: C. The head of the cartridge case contains the primer pocket and provides support for the primer.
21. These are firearm characteristics determined by microscopic random imperfections produced during manufacture, wear, tear, rust, and abuse, which serve as the basis for positive identification:
A. Class characteristics
B. Accidental characteristics
C. Individual characteristics
D. Manufacturing specifications
Answer: C. Individual characteristics
Unlike class characteristics (e.g., caliber, number of lands and grooves), individual characteristics are random microscopic imperfections unique to a single firearm that allow examiners to positively identify a fired bullet or shell as having come from that specific weapon.
22. Microscopic fine parallel scratches etched onto the surface of a bullet as it passes through the rifled barrel of a gun are called:
A. Land impressions
B. Striations
C. Skid marks
D. Wipe marks
Answer: B. Striations
Striations (or striae) are microscopic tool marks/scratches produced inside the barrel during machining or through wear and tear. They transfer onto the bullet as individual characteristics.
23. Which tool or instrument is primarily used by forensic ballisticians to observe individual characteristics by comparing a evidence bullet alongside a test-fired bullet?
A. Stereoscopic Microscope
B. Comparison Microscope
C. Scanning Electron Microscope
D. Compound Microscope
Answer: B. Comparison Microscope
Explanation: Magnification to match striations and individual tool marks.
24. Which type of mark may be left on a cartridge case as it is stripped from the magazine and fed into the chamber of a firearm?
A. Firing pin impression
B. Extractor mark
C. Magazine lip mark
D. Breechface mark
Answer: C. Magazine lip mark
A magazine lip mark may be produced when the cartridge case contacts the lips of the magazine as the cartridge is stripped from the magazine and fed into the chamber. Such marks may provide useful microscopic characteristics in firearm examination.
25. Marks impressed upon the head/base of a cartridge case when the expanding gas forces the cartridge backward against the rear wall of the chamber are called:
A. Ejector marks
B. Extractor marks
C. Breechface marks
D. Firing pin impressions
Answer: C. Breechface marks
Explanation: Microscopic tool marks on the soft primer and base of the cartridge.
26. Striations found on the sides of a bullet caused by the lands and grooves of a worn or defective barrel are classified as what type of characteristic?
A. Individual characteristic
B. Class characteristic
C. Temporary characteristic
D. Chemical characteristic
Answer: A. Individual characteristic
While the broad dimensions of lands and grooves are class characteristics, the minute striations inside them caused by tool wear, erosion, or corrosion are individual characteristics.
27. What unique mark is left on the rim or groove of a fired cartridge case when the claw-like mechanism pulls it out of the chamber?
A. Ejector mark
B. Extractor mark
C. Chamber mark
D. Firing pin mark
Answer: B. Extractor mark
The extractor is the mechanism that hooks onto the rim/groove of the cartridge to withdraw it from the chamber after firing, leaving distinct individual tool marks.
28. Which of the following is considered a CLASS characteristic rather than an INDIVIDUAL characteristic of a firearm barrel?
A. Microscopic tool marks on the rifling land
B. Rust pitting inside the bore
C. Direction of twist (Right or Left)
D. Gouges caused by improper cleaning methods
Answer: C. Direction of twist (Right or Left)
Direction of twist, caliber, and the number/width of lands and grooves are determined before manufacture and are shared by all weapons of the same make and model (Class characteristics). The rest are individual imperfections.
29. A mark left on the head of a cartridge case when it is forcibly flipped out of the firearm's ejection port by a small metal projection is called a/an:
A. Extractor mark
B. Ejector mark
C. Shearing mark
D. Firing pin indent
Answer: B. Ejector mark
The ejector strikes the base or side of the fired cartridge case to kick it out of the weapon, leaving an individual contact mark.
30. Why are individual characteristics essential in forensic ballistics during court proceedings?
A. They identify the caliber and weapon type used in the crime.
B. They determine the distance from which the gun was fired.
C. They provide a basis for associating a fired bullet or cartridge case with a particular firearm.
D. They reveal the manufacturer and year of production of the gun.
Answer: C.
They provide a basis for associating a fired bullet or cartridge case with a particular firearm.
Individual characteristics are unique like fingerprints; they provide the scientific basis for an expert witness to testify that a specific bullet or shell was fired from one specific gun.
Forensic Report Writing and Laboratory Safety Review Questions 1
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