Lecture 1: Fire Analysis Flashcards
What is Forensic Science
application of science to law
what is science
the systematic organization of information on a topic
to be accepted in court evidence has to be:
testable and validated through founded science theories
NAS 2009 Report
stated that forensic science is questionable and lacks peer reviewed papers
SWG is:
scientific working groups that provided standards is doesnt exist now
NIST & OSAC
it is the modern equivalent of SWG that is funded by the government proving standards and resources for the forensics community
OSAC process
1 Terminology
2 Validation standards
3 Quality Standards
4 Collection & Storage
5 Notes Reports and Testimony Standards
Ballistics
study of an objects flight study of firearms
hand gun
one handed gun (ie revolver, semiautomatic)
Why is it important to keep up with firearm news
It can help you identify new weapons and modifying weapons trends
revolvers
revolving cylinder, swings out to load & unload, cocks hammer as it revolves
semi-automatic
magazine with spring loaded bullets, one bullet per trigger
squib round
where the bullet gets stuck within the barrel and could possibly explode
single action
hammer is cocked each time
double action
the gun will cock itself
rilfes
one bullet per trigger, expel cartridge, reload, cock
why do squib rounds happen
there might not have been enough gun powder in homemade bullets
bolt action rifles uses _____ to cock and unload
a lever
semi-automatic rifle
when firing expels cartridge
automatic
machine gun
shot gun
smooth barrel, can fire shots or slugs
what is choke
when the end of the barrel gets smaller to get less range
diameter is gauge which is measured by
number of lead ball that will amount to the weight of 1 lead ball that is the diameter of the gun
what is rifling
spiraling on the inside of the barrel it is a class characteristics
Broach rifling is
a large steel rod with spaced cutting rings which is inserted into the barrel and slowly turned
button rifling
steel plug forced in barrel at a high pressure and polishes at the same time
hammer rifling
bigger barrel with steel mandrel in the barrel then the barrel is hammered into the mandrel
what is seen in hammer rifling
polygonal rifling
what is bore diameter
it is the diameter between the lands
what is caliber
is the approximate bore diameter (not exact)
what kind of ammunition do handguns and rifles use
uses single projectile with propellant and primer
what kind of ammunition do shotguns use
they use shots/pellets held together by wadding then shot with propellant and primer
Lead alloy bullets
fully lead bullet with small amounts of other metals
fully jacketed bullets
has a lead core with either copper/nickel/steel wrapping
semi-jacketed bullets
like fully jacketed but the tip is left exposed, allows for mushrooming
what is mushrooming
where the tip of the bullet expands outward when target is hit, causes more damage
what is propellant made out of
made out of smokeless gun powder which is made out of nitrocellulose + stabilizers
primer is a
small metal cup (percussive sensitive material) is struck by firing pin igniting lead, antimony, barium
