What general rifling characteristics of a firearm can be determined from a fired bullet?
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In what ways can the caliber of a firearm be determined from a fired bullet?
Caliber is a term used to indicate the diameter of a bullet in hundredths of an inch so if an examiners finds the size of the bullet, they can determine the caliber of the firearm
What class characteristics of a firearm can be determined from an expended cartridge?
#NAME?
What markings on fired bullets are compared microscopically?
- the examiner searches the surface of one bullet for a distinctive pattern of parallel 'striations' and then rotates the other bullet slowly in an attempt to find a matching pattern
- skid marks are also compared
- slippage marks are also compared
What markings on fired cartridge are compared microscopically?
firing pin impressions and breechblock markings also called bolt-face signatures
What conclusions can a firearms examiner reach as result of a microscopic comparison of bullets or cartridges?
#NAME?
How is the range of fire estimated from a powder pattern?
requires that the firearms examiner test fire powder patterns at various ranges until he or she is able to reproduce the original pattern in size and density of gunshot residue deposition
- must use the same firearm and ammunition that was used in the ori
How can the range of fire be estimated from a shotgun pellet pattern?
- when a shotgun is fired, the pellet mass spreads lately. Thus, pellet patterns fired at different ranges have different sizes and different shot densities.
- the firearms examiner needs the original pellet pattern, the shotgun used to fire the pattern,
What are the three types of tool marks?
- compression tool marks - result when a tool is pressed into a softer material
- sliding tool marks - are created when a tool slides along a surface; such marks usually consist of a pattern of parallel striations
- cutting tool marks - a combo of compres
How should tool marks be processed at the scene of a crime?
one a tool mark is found, the crime scene technician must take are to prevent alteration of the mark. He or she must make sure that no one attempts to fit a suspect tool into a tool mark; to do so risks alteration of the mark and would vitiate the value o
What conclusions can a firearms examiner reach as result of a microscopic comparison of tool marks?
- Positive identification - the class characteristics are consistent and individual characteristics match
- Negative identification - the tool mark was not made by the submitted tool. The characteristics did not match
- Inconclusive -this means that the c
The energetic material in a single-base smokeless powder is ______; the energetic materials in double-base smokeless powders are _____ and _____
nitrocellulose
nitroglycerin
In a rifled gun barrel the raised areas are called _____, and the recessed areas are called _____
lands
grooves
Cut rifling methods are ____, ____,and _____
hook cutting, scrape cutting, and broaching
Barrels with polygonal rifling are made by ______
hammer forging
The two types of metallic cartridge priming systems are _____ and ______
rimfire cartridge and centerfire cartridge
Markings made on the bases of cartridges by breech blocks are also called _____
bolt face signatures
Three commonly used chemical methods for the visualization of powder patterns produced by ammunition having lead-based primers are ____, _____, and ______
The Griess Test, Maiti Test, and sodium rhodizonate test
______ reagent is used for visualization of powder patterns fired with ammunition containing lead-free primers
sodium rhodizonate
An irregular, blown entrance wound in the skull is termed a _____ defect.
stellate
The ring of bullet lubricant, gunpowder combustion products and metal from the bullet surface surrounding a gunshot wound is called ______
gray ring
_____, _____, and _____ have been used to make casts of tool marks
Negative moulage, low-melting metal allows, and silicone rubber