Ballistics Flashcards
What is rifling?
Grooves inside the barrel, increasing accuracy by making bullets spin
What are the 2 parts of rifling to look for?
Lands (raised) and grooves (lowered)
What is calibre?
Numerical approximation of diameter of bullet
What is calibre different from?
Diameter ( barrel is deliberately smaller)
3 different types of cartridges
Rimmed, semi rimmed and rimless
Where are firing pin marks found?
Head stamp
What is the head stamp?
The bottom of a cartridge case
What can we tell from spotting?
How far away from the target the weapon and firer were
What class characteristics can you get from breech faces?
None (no known class characteristics)
What is in the middle of an automatic cartridge?
Propellant
What is inside a shotgun cartridge?
Shot and propellant powder
What is unique to a shotgun cartridge?
Plastic wadding
What gun does not have rifling in the barrel?
Shotgun
Who is needed when a firearm/weapon is found?
ARV (armed response vehicle)
What do you need from ARV before handling a firearm?
Red label - confirms weapon has been made safe
What is the general rule for determining distance from shotgun spread?
2.5cm per metre
What can affect the accuracy of determining distance from shotgun spread/ spotting?
Choke (narrows spread, if found, makes distance inaccurate)
What can you get DNA from on ballistics evidence found?
UNFIRED cartridges
How long does GSR stay on hands?
2-4 hours
What is at the bottom of the cartridge?
Primer
Difference of cartridges on revolvers and semi-automatic weapons
Cartridge stays in a revolver;
Cartridges in a magazine in a semi and ejected when fired
How long does GSR stay on the face or hair?
6-12 hours
How long does GSR stay on the surface of clothing?
24 hours
How long does GSR stay on the inside of objects (clothing pockets, cars etc)
Indefinitely
