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Flashcards in Ballistics Deck (47)
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1
Q

What are the 3 study areas of ballistics?

A
  1. Internal ballistics
  2. External ballistics
  3. Terminal/wound ballistics
2
Q

What is ballistics?

A

The science if travel of a projectile in flight

3
Q

What is internal ballistics?

A

The approximately 2ms timespan between the impact of the firing pin/striker and the exit of the projectile, the time when the projectile receives the characteristic markings that may be linked to the firing weapon

4
Q

What is external ballistics?

A

The flight of the projectile after leaving the barrel - bullet trajectory, gunshot residue patterns and distance determination are made in this phase

5
Q

What is terminal/wound ballistics?

A

What takes place when the projectile strikes the target - enters ve and exit wounds, bullet wipe

6
Q

What is bullet wipe?

A

The material deposited by the bullet on its target or any structure it may contact during its flight

7
Q

What are the characteristics of bullet wipe?

A
  • may be derbis from the barrel collected by the bullet
  • composed of soot, lubricant and particles of primer and metal fragments
  • may be present when no GSR can be detected
8
Q

What is a hand gun?

A

Short barrelled firearm (has a rifled barrel)

9
Q

What is the sight?

A

Device used to assist the alignment/aiming of the weapon

10
Q

What is the barrel?

A

Tube through which the projectile is propelled at high velocity, can be smooth or grooved

11
Q

What is the muzzle?

A

End of the barrel that the projectile exits from

12
Q

What is the hammer?

A

When the trigger is pulled, the hammer swings to impact the primer and initiate firing

13
Q

What is the trigger?

A

Mechanism that activates the firing sequence of a firearm

14
Q

What are the 3 broad categories of firearms?

A
  1. Rifle
  2. Shotgun
  3. Handgun
15
Q

What are the different action types of firearms?

A
  • single shot
  • repeating
  • self loading
  • fully automatic
16
Q

What is a rifled barrel?

A

A barrel with helical grooves cut lengthwise into the inside of the barrel which causes the bullet to spin along its axis upon exit from the barrel

17
Q

What does the spin in a rifled barrel do?

A

Serves to gyroscopically stabilise the projectile and improve aerodynamic stability and accuracy

18
Q

Which types of firearms have rifled barrels?

A

Rifle and handgun

19
Q

What is a rifle?

A

Shoulder weapon with a grooved barrel, initially a single shot weapon

20
Q

What is a handgun?

A
  • firearm with a shorter barrel - gun is designed to be shot with 1 or 2 hands
  • designed to fire batches of small projectiles
  • target a wide area but don’t travel long distances
21
Q

What is a projectile?

A

Any object propelled by the exertion of force

22
Q

What are the components of a cartridge?

A
  • case: generally brass, nickel or steel
  • primer: an ignition for the propellant
  • powder: propellant (gunpowder)
  • bullet: solid projectile that leaves the firearm
23
Q

What are the 2 main locations of primer?

A

Centre and rim

24
Q

What is rimfire ammunition?

A

The firing pin will strike the rim at the end of the cartridge which ignites the internal primer

25
Q

What is centrefire ammunition?

A

The primer is installed in a small gap in the centre of the base, requires a much stronger firing pin to strike

26
Q

What is callibre?

A
  • the approximate interna diameter of the barrel, measured between the lands of a rifled barrel
  • the larger the number, the wider the barrel
27
Q

What is gauge?

A
  • the unit of measurement for bore diameter, based on how many rounds you could make for the gun with 1 pound of lead
  • the smaller the number, the wider the barrel
28
Q

What is weapon examination based on?

A
  • gunshot residue
  • cartridge cases
  • bullet fragments
  • rifling patterns
29
Q

A gunshot wound to the skull will be beveled in the direction….

A

That the projectile travelled

30
Q

What is weapon examination based on?

A
  • gunshot residue
  • cartridge cases
  • bullet fragments
  • rifling patterns
31
Q

What are the different types of shell casing characteristics?

A
  • beech markings
  • firing pin marks
  • extracting pin marks
  • ejector marks
32
Q

What are the characteristics of striations?

A
  • number of groove or land impressions
  • direction of twist
  • measure of the rifling impression
33
Q

What is muzzle energy?

A

Kinetic energy as a bullet is expelled from a firearm

34
Q

What are the forces that act on a projectile?

A

Gravity: downward acceleration (bullet drop)
Drag: air resistance
Wind: deviates projectile from trajectory

35
Q

How can the distance between the gun and victims be estimated?

A

Looking at gunshot residue patterns

36
Q

Long distance

A

No GSR on victim

37
Q

Close-range

A

GSR on victim: spread out

38
Q

Near-contact

A

GSR on victim : concentrated circle

39
Q

Contact shot

A

“Blown out” entrance wound

40
Q

What is the permanent cavity?

A

The track made by the diameter of the bullet

41
Q

What is the temporary cavity?

A

Pressure wave caused by the bullet (higher velocity, larger the size)

42
Q

Exit wounds are ……… than enterance wounds

A

Larger

43
Q

What is GSR analysed with?

A

SEM and X-ray analyser

44
Q

What is GSR analysed for?

A
  • trace amounts of lead, barium and antimony

- elements such as aluminium, silicon, Sulfur potassium and calcium

45
Q

What is wound ballistics?

A

The medical effects of projectiles on humans

46
Q

What is penetrating trauma?

A

Injury when an object pierces the skin

47
Q

What is GSR?

A
  • the burned and unburned primer and propellant particles which are deposited as a cloud of material expelled from the barrel after firing
  • GSR particles form as a result of rapid cooling of the discharge gases and solid matter