Firearms Flashcards
Which guns are illegal?
Imitation firearms Sub machine guns Teasers Gs gas Barrel < 30cm whole thing less than < 60cm (handguns
Which guns are legal with a license?
Shotgun
Bolt action rifle
Air rifle
Cross bow
What is rifling?
Grooves (flatter portion, recessed) and lands (raised portion, prominent) features in the bore of a gun
What is broach rifling?
Steal rod with several cutting rings placed down the rod. Each successive ring is larger in diameter
This is forced down the barrel and twisted
What is button rifling?
Most common form of rifling where a hard steal plug is forced into the barrel
What is hammer forged rifling?
Hardened steel block is formed to lands and grooves and placed down a blank barrel
The barrel is machine hammered to form a mould of the steel inside, which is then removed.
What is polygonal rifling? Why Is it hard to examine?
No distinct transition between lands and grooves so takes the shape referred to as hills and valleys. The gradual transition makes it harder for examiners to measure lands/ grooves
What is the twist rate? What is it measured in?
Distance for a bullet to make one full rotation. Measured in inches.
What happens if the twist rate is too high?
yaw (bullet loses momentum)
Lower accuracy
Keyholing (elongating the hole in target)
What happens if the twist rate is too low?
Barrel wear
High velocity bullets can be torn apart by centrifugal force
Inconsistency in bullets could be magnified decreasing accurac
What is the equation for twist rate?
150xD(squared)/l
D = bullet diameter l= bullet length
What is the degree so the destruction in terminal ballistics dependent on?
Mass
Velocity
Surface nature
Design on projectile
What is impulse?
A change in the momentum of an object which force causes
How do you calculate impulse?
Mass x (final velocity v - initial velocity u)
How do you calculate force?
Impulse/time
