QuestionThe inner surface of the barrel of a gun

leaves its markings on a bullet passing through it. These markings are peculiar to each gun. Would these markings be considered class characteristics or individual characteristics?

AnswerBoth. The lands, grooves and twists are

class evidence while the microscopic striations are considered individual evidence.

QuestionWhat is the purpose of rifling, or impressing

the inner surface of a barrel of a gun with spiral grooves?

AnswerThe grooves serve to guide a fired bullet

through the barrel, imparting a rapid spin to insure accuracy and optimum distance.

QuestionThe surfaces of the original bore

remaining between the grooves are called __________.

AnswerLands

QuestionThe diameter of the gun barrel,

measured between opposite lands, is known as _____.

Answercaliber

QuestionTrue or False?Once a manufacturer chooses a rifling

process, the class characteristics of the weapon’s barrel will remain consistent, each will have the same number of lands and grooves, with the same approximate width and direction of twist.

AnswerTrue

QuestionTrue or False?No two rifled barrels, even those

manufactured in succession, will have identical striation markings.

AnswerTrue

QuestionThe single most important tool to a

firearms examiner is the ____________.

AnswerComparison Microscope

QuestionUnlike rifled firearms, a shotgun has a____________ barrel.

Answersmooth

QuestionThe diameter of the shotgun barrel is

expressed by the term _________. The ________ this number is, the _________ the barrel’s diameter.

AnswersGaugeHighersmaller

QuestionThe shape of the _______________will be

impressed into the relatively soft metal of the primer on the cartridge case.

AnswerFiring pin

QuestionThe cartridge case, in its rearward

thrust, is impressed with the surface markings of the _________________.

Answersbreechblock

QuestionWhat do you call the rear part of a firearm

barrel?

AnswerThe Breechblock

QuestionThe interior of a firearm barrel.

AnswerBore

QuestionThe cut or low-lying portions between the

lands in a rifled bore.

AnswerGrooves

QuestionThe spiral grooves formed in the bore of a

firearm barrel that impart spin to the projectile when it is fired.

AnswerRifling

QuestionFactors such as barrel length, caliber, type of

ammunition, and type and condition of the weapon fired influence the amount of gunpowder residue deposited on a target. True or False?

AnswerTrue

QuestionDistinctive markings that may appear on

the shell as a result of metal to metal contact can be caused by the _____________which is the mechanism in a firearm that throws the cartridge or fired case from the firearm.

AnswerEjector

QuestionDistinctive markings that may appear on

the shell as a result of metal to metal contact can be caused by the __________which is the mechanism in a firearm by which a cartridge of a fired case is withdrawn from the firing chamber.

AnswerExtractor

QuestionDistinctive markings that may appear on

the shell as a result of metal to metal contact can be caused by the __________which is the mechanism that in a firearm holds the bullets.

AnswerMagazine or clip

QuestionThese are fine lines found in the interior

of the barrel. They are impressed into the metal as the negatives of minute imperfections found on the rifling cutter’s surface, or they are produced by minute chips of steel pushed against the barrel’s inner surface by a moving broach cutter.

AnswerStriations

Questions

During the initial phase of comparison between an evidence bullet and a test-fired bullet, what characteristics are often looked at first?

AnswerClass characteristics such as grooves, lands

and twists.

QuestionNot only must the lands and ___________ of

the test and evidence bullet have identical widths, but the ____________________ striations on each must coincide.

AnswerGrooves,Longitudinal

QuestionThe NIBIN was eliminated the need for

forensic ballistic specialists. True or False?

AnswerFalse - the ultimate decision for making a

final bullet comparison will be determined by the forensic examiner through traditional microscopic methods.

QuestionThis network produces database files

frombullets and cartridge casings retrieved

fromcrime scenes or test fires from retrieved

firearms, often linking a specific weapon to multiple crimes.

AnswerThe National Integrated Ballistics

InformationNetwork, NIBIN

QuestionA star-shaped (stellate) tear pattern

around the bullet hole entrance, surrounded by a rim of a smokeless deposit of vaporous lead usually indicates a weapon discharge of ________________ from the target.

AnswerOf less than one inch

QuestionA halo of vaporous lead (smoke)

deposited around a bullet hole is normally indicative of a discharge of ______________or less.

Answer12 to 18 inches

QuestionThe presence of scattered specks of

unburned and partially burned powder grains without any accompanying soot is normally indicative of a discharge observed at distances ________________.

Answerup to 25 inches (and occasionally as far

as 36 inches).

QuestionDischarges that occur more than three

feet from the target will usually not deposit any powder residues, and the only visual indication is a dark ring around the hole, known as a __________________.

AnswerBullet wipe

QuestionWhat is the test used to detect gunpowder

residues that are not visible?

AnswerGreiss Test

QuestionRestoration of serial numbers is possible

through ____________________because the metal crystals in the stamped zone are placed under a permanent strain that extends a short distance beneath the original numbers.

chemical etching

QuestionWhen shoe and tire marks are impressed

into soft earth at a crime scene, their preservation is best accomplished by ___________ and _______________.

AnswerPhotography and casting

QuestionA sufficient number of _________________or

the uniqueness of such points will support a finding that both the questioned and test impressions originated from one and only one source.

Answerpoints of comparison

QuestionThe scene investigator should attempt to

fit the suspect tool into the tool mark in order to make sure the correct tool is being sent to the crime lab.

AnswerFalse, Any contact between the tool and

the marked surface may alter the mark and will, at the least, raise serious questions about the integrity of the evidence.

QuestionA _________________is considered to be any

impression, cut, gouge, or abrasion caused by a tool coming into contact with another object.

Answertool mark

QuestionA careful examination of the impression

can reveal important class characteristics, such as the _______________________________ of the tool.

Answer

the size and shape

QuestionIt is the presence of any minute

imperfections on a tool that imparts _______________to that tool.

Answerindividuality

QuestionA forensic _________________may conclude that

a bite mark was made by a particular individual if a sufficient number of points of similarity between test and suspect marks are present.

Answerodontologist

QuestionName a projectile that is not expected to

show any evidential marks or impressions.

AnswerA shotgun pellet

QuestionTrue or False?In collecting and packaging firearms

evidence at a crime scene, an investigator must mark a fired bullet on its base for identification.

AnswerTrue

QuestionTrue or False?In collecting and packaging firearms

evidence at a crime scene, an investigator must avoid inserting a stick or pencil into the barrel of a weapon.

AnswerTrue

QuestionTrue or False?In collecting and packaging firearms

evidence at a crime scene, an investigator must mark an empty bullet on its base for identification.

AnswerFalse

QUESTIONTrue or False?In collecting and packaging firearms

evidence at a crime scene, an investigator must unload a weapon before shipping it to the crime laboratory.

AnswerTrue

QuestionIdentify the two elements detected on the

hands of an individual who has recently fired a bullet are:

AnswerBarium and Antimony