Module 5 Intro to Firearms from Dr. Henwood

TYPES OF FIREARMS gen types

Revolvers, Pistols, Rifles, Shotguns, 

Revolvers: Designed to be gripped with…..

one hand

Revolvers: Breech-loading, rotating cylinder resulting in….

multiple chambers

Pistols: Designed to be gripped with….

one hand

Pistols (2 char.)

Integral chamber ■ Automatic (semi or full)

Pistols: _____ per trigger pull

Single-shot

Rifles: Designed to be…

shoulder fired

Rifles: Fires a…..

single projectile through a rifled barrel

Rifles: Categorized by…

firing mechanism

Rifles: Categorized by firing mechanism:

bolt, semi-automatic, pump action, lever action, etc

Shotguns: Designed to be…

shoulder fired

Shotguns: Fires _____ projectiles through a _____

single or multiple, smooth barrel

Shotguns: Shells with multiple projectiles

(shot)

Shotguns: Shells with single projectiles

(slugs)

Shotguns: Categorized by…

action/firing mechanism

Shotguns: Categorized by action/firing mechanism:

break action, semi-automatic, pump action, lever action, etc.

Major Components of Firearms

stock/pistol grip, action, barrel

Why is there rifled barrels?

So the bullet shoots straight

Calibre ■ Commonly known as…

the “size” of ammunition fired through a firearm.

Calibre: Distance between…

opposing land regions (original bore diameter before rifling)

Bullet anatomy: Most modern cartridges have similar …

basic design and component parts

Ammunition Anatomy (4 pts)

Primer – Propellant – Cartridge Case – Projectile(s)

Ammunition Anatomy:

bullet

Ammunition Nomenclature: 7.62 × 39mm : what do those numbers mean?

Nominal bullet diameter (calibre) x case length *unit of measure

Headstamps ■ Usually contains production information such as: (5)

Manufacturer – Plant – Calibre – Year of manufacture – Additional information- ex. NATO

Cartridge Case Shape (2)

straight, necked (bottle necked)

Types of Bullets: 4 gen ones to know

Jacketed hollow point (JHP), lead round nose (LRN), Full metal jacket (FMJ), Jacketed soft point 

What kind of bullet is this ?

Jacketed Hollow Point (JHP) 

What kind of bullet is this ?

Lead round nose  (LRN)

What kind of bullet is this ?

Full metal Jacket (FMJ)

What kind of bullet is this ?

Jacketed soft point (JSP)

Shotgun Ammunition: ________ held within the case

Multiple projectiles

Shotgun Ammunition: Case holds projectiles until ________ wad propels them….

exiting the barrel, outward during flight

Shotgun Ammunition: Used when….

multiple impacts may be required to increase hit likelihood

Shotgun Ammunition: Examples of when it might be used? (2)

Hunting, drones/UAV takedown

Shotgun Ammunition Nomenclature: Gauge

(diameter of the barrel)

Shotgun Ammunition Nomenclature: Gauge (diameter of the barrel) – Common sizes include… (4)

10, 12, 16, and 20 gauge

Shotgun Ammunition Nomenclature: Shell length

(chamber length- very important)

Shotgun Ammunition Nomenclature: Shell length (chamber length- very important) – Typically….. (3)

2 ¾ inches, 3 inches or 3 ½ inches

Shotgun Ammunition Nomenclature: Types of Shot

Birdshot, Buckshot, Slugs

Shotgun Ammunition Nomenclature: Shot Size

Size of individual pellets - #4, #7.5, etc

Forensic Ballistic evidence: Characteristics

Class, subclass, Individual

Forensic Ballistic evidence: Characteristics: class

General and/or measurable features of a specimen which indicate a restricted group source. They result from design factors and are therefore determined prior to manufacture. – Calibre, number of lands/grooves, twist direction.

Forensic Ballistic evidence: Characteristics: Individual:

Marks or features produced by the random imperfections or irregularities of tool surfaces. These characteristics can be used to individually associate a tool to a toolmark. – May be produced during manufacture, by wear through use or by wear through abuse

As the bullet is forced down the barrel of the firearm, the marks from the…..

rifling in the hard steel are imparted into the softer material of the bullet.

Bullets: These striations are compared using….

microscopy to determine if the bullet(s) collected from a crime scene/victim passed through the same barrel that was tested in the forensic lab.