Ballistics Flashcards
Explain why ballistic science is important?
Firearms were used in:
69% of the US murders
40% of robberies
21.6% of aggravated assaults
Handguns can be held and fired with ______. They are divided into ___ categories. Name them
one hand 3 revolvers semiautomatic pistols machine pistols
- Handguns
Revolvers have a _____ to hold bullets and short _____.
One pull of the trigger = ___ shot.
Shell casting remains in the ______ after firing.
cylinder cartridges
1
cylinder
- Handguns
Semiautomatic pistols have a ____ or a ____.
Each shot = __ shot.
empty shells are automatically _____.
magazine or clip
1
removed
- Handguns
Machine pistols, automatic. It fires ______ (as long as ______).
___ similar to semiautomatic pistols.
repeatedly
there is ammunition
clip
Rifles often use a ____ or a sliding ___ to eject the spent cartridge. They can be ___ or _____.
lever blot
automatic or semiautomatic
Shotguns don’t fire ____, but _____ filled with groups of ___. Those spread out in ____ pattern and the shot spread about an inch for each ___ feet of travel.
bullets shells pellets circular 3
Shotguns have no ___ in the barrel, so no ____ marks.
grroves
identifying
Intact bullets are ____ found, so bullets often considered _______.
rarely
trace evidence
How can we find the manufacturer of the gun?
chemical and physical composition of the bullet. powder in the bullets.
What information can be found with a recovered bullet?
1- a type of gun
2- trace evidence: paint, fibers
3- DNA flesh and blood.
What are the 3 limits of ballistic science when it comes to recovered bullets?
1- severely deformed
2- too small
3- damaged during recovery
____ bullets are soft, deform and fragment as they reach the target and they cause ____ damage.
Lead
tissue
Lead ___ bullets are different than Lead bullets because they are mixed with ____ and ____. They deform and fragment (more/less) than lead bullets.
Also, they have (more/less) penetrability.
alloy
tin antimony
less
more
Semijacketed bullets have a thin layer of ____ on the side.
They ____ and fragment upon impact.
brass
expand
Fully jacketed bullets are ____ covered with brass. They have a ___ penetrating power. They can penetrate body armour which is why they are called ______. Their jacket is made of ___, ____ and other synthetics.
completely
greater
cop killer
Teflon, nylon
How do we calculate the calibre of a gun?
How do we calculate the gauge of a gun?
1- measurement of the internal diameter of the barrel. in inches or mm
2- number of balls that can fit in the barrel diameter - inverse relation.
The shell casing is the part of the bullet that ________.
It retains marks such as:
impression left by the ______ (centre-fire or rim-fire)
_____ pattern
_________
_____ or ejector marks.
remains after the powder explodes and the bullet is gone. firing pin breechblock headstamps extractor
The rifling pattern helps link a ____ to a _____.
bullet
gun/gun type
Spiral grooves are inside the _____ and make the bullet ____. They make the shot more _____ and create marking that can be used in forensic.
barrel
spin
precise
depending on the manufaturer:
the____ of the grooves, the _____ of the lands, the direction (______/_______), and the ____ of the twist.
depth
width
clockwise/counterclock
degree
What are the three things that can link the bullet to a gun (simply with the rifling pattern)?
1- lands and grooves
2- twists
3- striations
What are the 3 limits of rifling patterns?
1- silencer
2- rifling patterns vary from barrel to barrel
3- when using a gun a lot, the grooves and the lands wear down.
What are the four steps to individualizing striations?
1- obtain intact bullet
2- compare the lab fired bullet + crime scene bullet
3- see if there is a match with a comparison microscope
4- identify or not the perpetrator
How many striations (consecutive) are necessary to have a match?
3
What is a gunshot residue and when is it used?
powder that explodes when the shot is fired.
When no gun, no bullets, no shell casing.
Where can GSR be found? 8
shooters hand arm clothing face hair walls furniture victims clothing
____ and ____ can change the pattern or lessen the spread of the GSR cloud.
wind and rain
GSR are visible on ______ clothing, but needs further testing on _____.
light-colored
dark
Firing distance can be estimated when GSR is found on the ____ of a victim. Only if there was no _____ in between.
wound
clothing
Firing distance can also be estimated if a pattern of GSR is found on the ______. The farther the distance, the ____ the spread. After a certain distance, ____ residue is found.
clothing
wider
no
People who get shot rarely die ______. Also, they will probably die of _____ or _____.
immediatly
exsanguination
infection
The character of the shot depends on: 4
1- distance between shooter and victim
2- caliber and velocity f the bullet
3- angle at which the bullet enters the body
4- whether the bullet remains or exits the body
When the bullet hits the victim, it creates an ____ wound and sometimes an ____ wound.
entry
exit
the bullet often (remains in/exits)____ the victim.
determining the entry and exit wound in crucial in _____.
remains in
reconstructing the crime scene.
Exit wounds are typically ____ because it gets ____ inside the body and ____ its ways out of the tissues.
larger
derformed
tears
____ bullets are easily deformed and create more damage as the bullet tries to exit the body.
softer
If the victim wears ___ clothing or is standing ___ a wall, the skin is ___ likely to tear. And the exit wound can look like _____.
tight
against
less
an entry wound
A shotgun creates ___ entry wounds, creating a ___ pattern which can help determine the ___ between the victim and the shooter.
multiple
shot
distance
Muzzle 2 feet or more creates:
Muzzle 6 inches to 2 feet creates: because?
muzzle less than 6 inches creates:
muzzle pressed against victim:
buising in a halo around the hole
speckles, gunpowder
area charring around the hole
ripping around the whole
