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33 terms

Chapter 17-18

VHCC
STUDY
PLAY
Firearms Identification
A discipline mainly concerneed with determining wheterh a bullet or cartridge was fired by a particular weapon; it is not to be confused with ballistics, which is the study of a projectile in motion
Grooves
The cut or low-lying portions between the lands in a rifled bore
Rifling
The Spiral grooves formed in the bore of a firearm barrel that impart spin to the prjectile when it is fired
Bore
the interior of a firearm barrel
Lands
The raised portion between the grooves in a rifled bore
Caliber
The diameter of the bore of a rifled firearm; the caliber is usually expressed in hundreadths of an inch or millimeters
Gauge
Size designation of a shotgun, originally the number of lead balls with the same diameter as the barrel that would make a pound.
Extracter
The mechanism in a firearm by which a cartridge of a fired case is withdrawn from the chamber.
Ejector
The Mechanism in a firearm that throws the cartridge or fired case from the firearm.
Distance Determination
The Process of determining the distance between the firearm and a target, usually based on the distribution of powder patterns or the spread of a shot pattern.
Choke
An interior construction placed at or near the muzzle end of a shotguns barrel to control shot dispersion.
Greiss Test
A chemical test used to develop patterns of gunpowder residues around bullet holes.
land
The ___ is the original part of the bore left after rifling grooves are formed.
comparison microscope
The single most important instrument for comparing bullets is the ________
False
If bullets were fired in succession from the same weapon, all the individual characteristics would always be identical
smooth
A shotgun has a_____barrel
False
Shotgun pellets can be individualized to a single weapon
NIBN
The automated firearms search system developed by FBI and ATF as a unified system incorporated both DRUGFIRE and IBIS technologies available in prior years is known as
tool mark
A ______is any impression caused by a tool coming into contact with another object
striations
Tool marks compare only when a sufficient number of ______ match between the evidence and test markings.
a photograph and liquid silicone cast
Objects bearing tool marks should be submitted intact to the crime lab or a ____________________ _______________
lifting sheets or a electrostatic lifting device
An imprint may be lifted using
photography and casting.
Shoe and tire marks impressed into soft earth at a crime scene are best preserved by
individual characteristics
wear pattern can impart ___________ __________to a shoe
Exemplar
An authentic sample used for comparision purposes, such as handwriting.
natural variations
Normal deviations found between repeated specimens of an individuals handwriting or any printing device.
Erasure
The removal of writing, typewriting, or printing from a document; it is normally accomplished by either chemical means or an abrasive instrument.
Infrared Luminescence
A property exhibited by some dyes that emit infrared light when exposed to blue-green light.
Obliteration
The blotting out or smearing over of writing or printing to make the original unreadable.
Charred Document
Any document that has become darkened and brittle through exposure to fire or excessive heat.
Indented Writings
Impressions left on papers positioned under a piece of paper that has been written on.
Duration, Balance, Wording, Pronouns, Placements, Social Intro, emotions, omissions, time, connections, editing,
Handwriting Analysis
Red and Blue Fibers, Watermark on right, color shifting ink, security thread, microprint.
What to look for on the Dollar Bills