Firearms
Examination
Examination
What is the purpose of a trigger pull test?
To determine the amount of force needed to release the trigger.
What instrument allows examiners to compare two bullets side-by-side?
Comparison microscope.
What does GSR stand for?
Gunshot Residue.
What conclusion can be made if class characteristics and striations match?
The bullet/casing may have been fired from the suspect firearm.
Name one type of external safety mechanism found on firearms.
Cross-bolt safety/ Pivot safety / Slide (Tang) safety.
What are the microscopic scratches on bullets called?
Striations.
Where is GSR commonly found on a suspected shooter?
On the hands and clothing.
What does a headstamp help identify?
Manufacturer, caliber, gauge, or cartridge information.
What is the primary purpose of firearm safety mechanisms?
To prevent accidental discharge.
State TWO class characteristics used in a bullet comparison.
Any two:
What is the most common method used to restore an obliterated serial number?
Chemical etching.
What two systems are commonly used to recover test-fired bullets?
Water tank and cotton recovery box.
What problem may occur if a firearm has a very light trigger pull?
Accidental discharge (hair trigger).
Why are test-fired bullets produced by examiners?
To compare them with evidence bullets recovered from a crime scene.
Which reagent is commonly used during serial number restoration?
Fry's Reagent.
What is the function of the transfer bar safety?
It transfers energy from the hammer to the firing pin and helps prevent accidental firing.
Name THREE cartridge case markings that can be used for firearm identification.
Any three:
Can GSR analysis identify the exact firearm used in a shooting?
No. It can indicate that a person may have fired or handled a firearm but cannot identify the exact firearm