FRNSC 411 EXAM 2 Graded A+ Verified 2024
3 ex of tools that make compression marks - ANSWER-hammers, pliers,
punches/chisels
3 ex of tools that make cutting marks - ANSWER-bolt cutters, wire cutters, shears/snips
3 ex of tools that make sliding marks - ANSWER-pry bars, screwdrivers, extrusion dies
6 common firearm actions (firing and reloading mechanisms) - ANSWER-1. revolver
2. semi-automatic
3. bolt action
4. lever action
5. pump
6. full-automatic
barrel blanks - ANSWER-solid bar of metal that is drilled, where a hole is drilled through
broach - ANSWER-a broach is a cutting tool featuring a series of progressively larger
teeth. as the broach is forced through a hole, each successive tooth cuts away a small
amount of material
bullet is usually jacketed with _______ but can be _____, coated in ________ -
ANSWER-copper, steel, nylon (Nyclad)
button rifling tool - ANSWER-creates the land and grooves in a barrel by pushing into
the barrel
the tool has little notches to make the lands and grooves
chamber - ANSWER-holds cartridge in place while firing
class characteristic - ANSWER-characteristics which are shared by a group of items
and are due to intentional choices made by the mannufacturer
compression tool mark - ANSWER-a harder item (Tool) is pressed perpendicularly into
a substrate, leaving an impression which is oriented as a mirror impression of the tool
surface
core of the bullet is - ANSWER-lead alloy, can be tin or tungsten (armor piercing AP)
Cutting toolmarks - ANSWER-generally exhibits characteristics of both compression
and striated toolmarks. typically the cutting edge first compresses the substrate
(producing a compression mark) then as the substrate yields/fractures, the cutting edge
slides along the newly formed edges, (producing a striated mark)
deterrent propellant - ANSWER-graphite glaze, centralite
, helps flatten out burn rate
difference between fully and semi automatic - ANSWER-fully: if you hold the trigger
down, it will continue to fire until it runs out of ammunition
semi automatic: reload automatically but do not fire automatically, you have to pull the
trigger for as much as you want to shoot
double base propellant - ANSWER-nitrocellulose and nitroglycerine
drill press - ANSWER-drill bit rotates
round holes, either 'blind' or 'through' holes (look at image)
examples of fire formed impressions/toolmarks - ANSWER-firing pin impression
breechface impression
firing pin aperture shear
ejector port mark
chamber mark
examples of non fireformed impressions/toolmarks - ANSWER-extractor impression
ejector mark
magazine mark
extrusion - ANSWER-a pliable solid material is forced through an opening under
pressure
the pliable solid assumes the shape of the opening as it passes through, allowing
material with complex shapes to be produced continuously
*think play dough fun factory/pasta machine
the tool that gives the shape is called a die
extrusion mark - ANSWER-due to build up at edge of opening of extrusion machine
it leaves longitudinal extrusion marks (striations)
factors affecting tool marks (impressions and striations) (8) - ANSWER-tool angel
longitudinal angle
substrate hardness
pressure
directionality
path
wear/weathering
alteration
flash suppressor propellant - ANSWER-potassium nitrate
four important notes about safety with guns - ANSWER-1. always point a firearm in a
safe direction
3 ex of tools that make compression marks - ANSWER-hammers, pliers,
punches/chisels
3 ex of tools that make cutting marks - ANSWER-bolt cutters, wire cutters, shears/snips
3 ex of tools that make sliding marks - ANSWER-pry bars, screwdrivers, extrusion dies
6 common firearm actions (firing and reloading mechanisms) - ANSWER-1. revolver
2. semi-automatic
3. bolt action
4. lever action
5. pump
6. full-automatic
barrel blanks - ANSWER-solid bar of metal that is drilled, where a hole is drilled through
broach - ANSWER-a broach is a cutting tool featuring a series of progressively larger
teeth. as the broach is forced through a hole, each successive tooth cuts away a small
amount of material
bullet is usually jacketed with _______ but can be _____, coated in ________ -
ANSWER-copper, steel, nylon (Nyclad)
button rifling tool - ANSWER-creates the land and grooves in a barrel by pushing into
the barrel
the tool has little notches to make the lands and grooves
chamber - ANSWER-holds cartridge in place while firing
class characteristic - ANSWER-characteristics which are shared by a group of items
and are due to intentional choices made by the mannufacturer
compression tool mark - ANSWER-a harder item (Tool) is pressed perpendicularly into
a substrate, leaving an impression which is oriented as a mirror impression of the tool
surface
core of the bullet is - ANSWER-lead alloy, can be tin or tungsten (armor piercing AP)
Cutting toolmarks - ANSWER-generally exhibits characteristics of both compression
and striated toolmarks. typically the cutting edge first compresses the substrate
(producing a compression mark) then as the substrate yields/fractures, the cutting edge
slides along the newly formed edges, (producing a striated mark)
deterrent propellant - ANSWER-graphite glaze, centralite
, helps flatten out burn rate
difference between fully and semi automatic - ANSWER-fully: if you hold the trigger
down, it will continue to fire until it runs out of ammunition
semi automatic: reload automatically but do not fire automatically, you have to pull the
trigger for as much as you want to shoot
double base propellant - ANSWER-nitrocellulose and nitroglycerine
drill press - ANSWER-drill bit rotates
round holes, either 'blind' or 'through' holes (look at image)
examples of fire formed impressions/toolmarks - ANSWER-firing pin impression
breechface impression
firing pin aperture shear
ejector port mark
chamber mark
examples of non fireformed impressions/toolmarks - ANSWER-extractor impression
ejector mark
magazine mark
extrusion - ANSWER-a pliable solid material is forced through an opening under
pressure
the pliable solid assumes the shape of the opening as it passes through, allowing
material with complex shapes to be produced continuously
*think play dough fun factory/pasta machine
the tool that gives the shape is called a die
extrusion mark - ANSWER-due to build up at edge of opening of extrusion machine
it leaves longitudinal extrusion marks (striations)
factors affecting tool marks (impressions and striations) (8) - ANSWER-tool angel
longitudinal angle
substrate hardness
pressure
directionality
path
wear/weathering
alteration
flash suppressor propellant - ANSWER-potassium nitrate
four important notes about safety with guns - ANSWER-1. always point a firearm in a
safe direction
