Ballistics Flashcards
How are shotguns classified?
By gauge
Gauge
The number of appropriately sized bullets that could be made from one pound of lead; the smaller the gauge, the bigger the bullet
Contents of a cartridge
Projectile
Propellant
Primer
Casing
Types of shotgun projectiles
Birdshot, buckshot, slug
Tool
A device or implement used to carry out a particular function
Firearm
A weapon from which a shot is discharged by gunpowder
Ballistics
The study of projectiles, trajectories, and the effect on the target
Firearms Identification
Methods to determine whether a bullet or cartridge was fired by a particular weapon
Barrel
Metal cylindrical part of a firearm through which the bullet travels
Muzzle
Discharging end of the barrel of a firearm
Chamber
Firearm compartment that holds the cartridge
What is the chamber of a rifle called?
The breech
What is the chamber of a revolver called?
The cylinder
Hammer/Striker
Part that hits the primer or firing pin or explodes the percussion cap, causing the gun to fire
Magazine/Cylinder
Detachable firearm component in which cartridges are held to be fed into the firing chamber
Types of firearms
Handguns, shotguns, and rifles
Handgun types
Revolver
Semi-automatic pistol
Shotgun types
Single shot
Pump action
Automatic
Rifle types
Single shots
Automatic
Three types of ballistics
Internal - travel within gun
External - gun to target
Terminal - wound ballistics
Casing materials
Steel
Brass
Aluminum
Nickle-coated brass
Caliber
Diameter of the bullet in either hundredths of an inch or mm or inside bore of the barrel
Why is the bullet actually slightly larger than the caliber?
So it fits snugly in the barrel, creates a seal, and doesn’t rattle around
Primer types
Center vs Rim
Berdan vs Boxer
Cartridge Identification
Manufacturer markings Markings by the process Extractor Breech Firing pin
Extractor
Hooks the cartridge and pulls it out to hit the ejector
Process markings
Firing pin marks Chamber marks Breech impressions Ejector Extractor
Gunpowder Identification
Granule shape (ball, flattened ball, flake, stick) Chemical composition
Methods of bullet identification
Metal composition
Caliber
Barrel Rifling
Common metal compositions
Copper
Zinc
Steel
Full Metal Jacket
Brass or copper coated; doesn’t fragment
Weight of a bullet is measured in…
grains
What type of bullet can penetrate armor
Steel centered bullets
Barrel rifling
Grooves cut into the barrel to spin the bullet, leaves marks on the bullet which can be used for identification (4/right, 6/right, 6/left, 16/right)
Types of bullet tracing (5)
Caliber, grains, and type Material it's made of Rifling pattern Distinguishing features Blood on the bullet
Preferred firearm for crime and why
Shotguns; no rifling and harder to trace
Greiss test
Tests for nitrates (unburned gunpowder) on clothing and suspect’s hand
Negatives of Greiss test
False negative - wash hands, gloves
Nitrates stop appearing after 48 inches
Higher velocity =
bigger impact
Air resistance is less effective in _____ altitudes
high
Physical ballistic evidence at the scene (4)
Wound entrance/exit
Final position of bullet
Environmental factors
Witness testimony
