1
What are the 4 parts of a firearm?
Hammer, firing pin, cartridge, barrel
What are the 4 parts of a cartridge?
Projectile, propellant, primer, case
Where is the primer located?
At the base of the cartridge
What are the 2 types of firearms?
Long guns and handguns
How is the caliber of a firearm measured?
In hundredths/thousandths of an inch or millimeters
The primer consists of which 3 elements?
Lead, barium, antimony
What kind of rifling does a shotgun have?
No rifling
Where are test bullets fired into and why?
Water tank; prevents damage to the bullet
What does smokeless powder consist of?
Nitrocellulose or Nitrocellulose and Nitroglycerin
What does a rifling pattern of a firearm contain?
Striations
Name at least 3 class characteristics of bullets
Caliber
Type
Manufacturer
# of lands/grooves
Width between lands/grooves
Twist pattern
What is GSR and name at least 3 places you can test for GSR
Gunshot residue; Hands, face, shirt, pants, floor
What is used to test for the presence of nitrates and what color does a positive result give?
Modified Griess Test, orange
What kind of microscope is used to examine the individual characteristics of a bullet?
Comparison microscope
Name 4 class characteristics of a cartridge case?
Manufacturer
Shape
Caliber
Compositions
What is used to test for the presence of lead and what color does a positive result give?
Sodium Rhodizonate, pink
Name 4 individual characteristics of a cartridge case?
Firing pin impression
Breech face marks
Extractor marks
Ejector marks
Name 2 characteristics of entry holes?
Smaller and cleaner compared to exit holes
Name 2 types of tools used to determine the path of the bullet
Lasers and trajectory rods
What kind of microscope is used as a confirmatory test for GSR?
Scanning electron microscope (SEM)
How is an extractor mark different than an ejector mark?
Extractor removes the empty cartridge from the chamber while the ejector removes the empty cartridge from the firearm
What are the raised portions in the barrel called and what are the indentations called?
Lands and grooves
What is NIBIN and what does it stand for?
Database for bullets and cartridge cases; National integrated ballistic identification system
What substances can give a false positive result when testing for nitrates and lead?
Fertilizer
Paint
Fireworks
Household cleaners
How is rifling produced and why is it important for a firearm to have?
Produced from a solid steel bar hollowed out by drilling; imparts a spinning motion to the bullet making it more stable and more accurate