Firearms and Ammunition

What are the three basic components of a firearm?

Barrel, ignition (hammer), and trigger.

The goals of firearm improvement include __________, __________, and __________.

Speed, Distance, Accuracy.

What type of firearm holds 6-8 bullets, can be single action or double action, rifled barrels, and is loaded manually?

Revolver

A shotgun has a __________ barrel and fires __________.

smooth, pellets

What are the components of a bullet used in handguns and rifles?

Casing, primer, propellant, projectile

A shotgun uses __________ for the diameter of the barrel; the lower the gauge, the __________ the diameter.

gauge, larger.

What is the primary component of black powder?

Charcoal, sulfur, and potassium nitrate

Smokeless powder (single-base) is mostly made of __________ and burns __________.

nitrocellulose, cleaner with little smoke

What differentiates smokeless powder (double-base) from single-base smokeless powder?

It contains nitroglycerin and burns faster and hotter

What is the composition of ammunition for a pistol?

Primer, cartridge case, gunpowder, bullet.

The class characteristics of bullets include __________, __________, __________, _________,_________, _________, _________, and _________.

caliber; manufacturer, composition, bullet shape, type of firing, direction of twist, degree of twist

What are the two types of tests for gunshot residue?

Presumptive and confirmatory

The Modified Griess Test tests for __________ and produces a __________ result.

nitrates; blue/black.

What does SEM stand for, and what is its primary use?

Scanning Electron Microscopy, it’s used to create high-resolution images of surfaces.

What is the main strength of Neutron Activation Analysis (NAA)?

Very accurate for detecting trace elements.

What is a comparison microscope used for in forensic analysis?

To compare two bullets or casings side by side.

What is a semi-automatic firearm?

A weapon that automatically reloads after each shot, firing one bullet per trigger pull, holds 10-15 rounds, and has extractor marks

What are shotguns primarily used for?

Hunting and sport shooting, firing a spread of pellets.

What differentiates rifles from other firearms?

A longer barrel and are designed for precise shooting, firing bullets individually.

What are the components of a bullet?

Casing, primer, propellant (gunpowder), and the projectile.

What are pellets in the context of shotguns?

Small spherical projectiles fired from a shotgun, designed to spread out upon firing.

What is the composition of ammunition?

Casing, primer, powder (gunpowder), and a projectile.

What are class characteristics of bullets?

Caliber, manufacturer, composition, round nose/ hollow point, center fire/ rim fire, direction fo twist, degree of twist.

What are individual characteristics of bullets?

Striation patterns

What are firearm class characteristics?

Type of gun, manufacturer, caliber, rifling present/absent, # lands & grooves, width of lands/grooves, firing pin impression appearance, extractor marks (semi & automatic), twist ratio

What are the components of a primer?

Lead styphnate, arium nitrate, antimony sulfide

What are propellants or gunpowders?

Black powder, single base, double base

How do tests for gunshot residue work?

They analyze the presence of lead, barium, and antimony to confirm gunshot discharge.

What is a positive control in testing?

A positive control ensures that the test is working properly by providing a sample known to produce a positive result.

What is a negative control in testing?

A negative control ensures that the test does not produce a false positive by using a sample known not to contain the target substance.

Why use controls in tests for gunshot residue?

Controls are used to validate the accuracy and reliability of the test results.

What patterns can be found in gunshot residue analysis?

Cone shape creates circular patterns when residue hits an object/person- wider the circle, the greater the distance between the shooter and target

What is a comparison microscope?

An instrument used in forensic analysis that allows two specimens to be viewed side by side for comparison.

How does a comparison microscope work?

It uses a dual optical system to allow simultaneous viewing of two samples, helping forensic experts in identifying matching characteristics.

What is a firearm?

A weapon capable of firing one or more projectiles, typically using the explosive force of gunpowder. Common types include handguns, rifles, and shotguns.

Firearm/bullet database

NIBIN