Bullet Velocity and Forces Test: Stripping Marks on Bullet Quiz

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Questions and Answers

What is the primary purpose of priming compounds in gun ammunition?

To provide the initial ignition of the gunpowder propellant (correct)

To provide a low-explosive mixture to propel the projectile

To draw moisture from the air and speed up corrosion in the gun barrel

To produce a grayish smoke when the gun is fired

What is the primary difference between corrosive and non-corrosive priming compounds?

Corrosive primers contain potassium chlorate, which can contribute to corrosion in the gun barrel, while non-corrosive primers do not (correct)

Corrosive primers produce a grayish smoke upon firing, while non-corrosive primers do not

Corrosive primers are an older technology, while non-corrosive primers are the more modern standard

Corrosive primers are more powerful and produce a greater explosive force, while non-corrosive primers are weaker

Which of the following is not a characteristic of black powder, the traditional European gunpowder?

Consists of irregular grains with a dull or shiny black surface

Contains a higher percentage of sulphur compared to modern smokeless powders (correct)

Produces a grayish smoke and leaves considerable residue in the barrel

Burns with great rapidity when ignited

What is the primary difference between erosion and corrosion in gun barrels?

Erosion is caused by the expansive force of the gunpowder, while corrosion is caused by rust formation Signup and view all the answers

What is the primary function of gunpowder, also known as the propellant or power charge, in small arms ammunition?

To generate the expansive force of gas that propels the projectile Signup and view all the answers

Who is credited with the invention of black powder, the earliest form of gunpowder?

Roger Bacon, an English monk and scientist Signup and view all the answers

What is the term used to describe the ability of a bullet to maintain its velocity against air resistance?

Ballistic coefficient Signup and view all the answers

Which of the following best describes the term 'yaw'?

The unstable rotating motion of a bullet Signup and view all the answers

What is the term used to describe the bouncing of a projectile after hitting a surface?

Ricochet Signup and view all the answers

Which of the following is the correct velocity range for a rifle bullet?

2,500 ft/sec Signup and view all the answers

What is the term used to describe the tumbling of a bullet in its flight and hitting the target sideways?

Keyhole shot Signup and view all the answers

Which of the following best describes the term 'drift'?

The curve taken by the bullet while in flight due to rifling Signup and view all the answers

What is the bore diameter of a firearm?

The distance measured between two opposite lands inside the bore Signup and view all the answers

How are lands defined in relation to a firearm's bore?

The elevated portion of the bore Signup and view all the answers

What is the function of rifling direction in a firearm barrel?

To ensure gyroscopic stability in flight by causing rotation Signup and view all the answers

How is pitch of rifling defined in a firearm barrel?

The measure of twisting of the lands and grooves Signup and view all the answers

What determines the width of the lands in a firearm's barrel?

The bore diameter, grooves width, and number Signup and view all the answers

What is meant by 'number of lands and grooves' in firearms?

The count of elevated and depressed portions inside the barrel Signup and view all the answers

What is the main difference between low explosives and high explosives?

Low explosives produce a dull 'boom' and push-type damage, while high explosives detonate with a sharp 'crack' and produce violent shattering damage Signup and view all the answers

What is the main characteristic of a detonation explosion?

It results from the sudden decomposition or combustion of unstable compounds Signup and view all the answers

Which of the following is NOT considered a high explosive?

Black powder Signup and view all the answers

What is the main characteristic of a pressure explosion?

It is caused by the sudden breaking apart, shattering or bursting in pieces due to internal pressure, as that of gas or steam Signup and view all the answers

Which of the following is NOT a characteristic of a bomb?

It is fired by a time fuse Signup and view all the answers

What is the main difference between low and high explosives in terms of their explosion velocities?

High explosives have higher explosion velocities than low explosives Signup and view all the answers

What are groove marks?

Marks found on a fired bullet caused by the grooves of the barrel, matching the number of grooves (lands) in the barrel Signup and view all the answers

What are skid marks in the context of firearms examination?

Marks found on fired bullets from a revolver, typically near the front due to the bullet's initial forward movement Signup and view all the answers

What causes stripping marks on fired bullets?

Worn-out rifling in the barrel due to corrosion or excessive use Signup and view all the answers

What are shaving marks, in the context of firearms examination?

Marks commonly found on bullets fired from a revolver due to a poorly aligned barrel Signup and view all the answers

What are slippage marks?

Marks found on fired bullets passing through an oily or oversized barrel Signup and view all the answers

Which of the following marks is considered one of the most important for firearm identification using fired cartridge cases?

Firing pin mark Signup and view all the answers

Study Notes

Priming Compounds

Corrosive priming compounds contain potassium chlorate, which produces potassium chloride when ignited, drawing moisture from the air and accelerating rusting and corrosion in gun barrels.
Non-corrosive priming compounds are mostly used today, consisting of:
- Potassium chlorate (initiator & fuel) - 45%
- Antimony (element & fuel) - 23%
- Fulminate of mercury (initiator) - 32%

Gun Powder

Also known as propellant or power charge, gun powder is a mixture of chemicals designed to propel a projectile by means of its expansive force of gas when burned.
Classified as a low-explosive mixture, gun powder burns rapidly upon ignition.
There are two types of powder in small arms:
- Black powder (Europeans) - oldest propellant powder, consisting of:
  - Potassium nitrate - 75%
  - Sulphur - 10%
  - Charcoal - 15%
- Characteristics:
  - Oldest propellant powder
  - Consists of irregular grains with a dull or shiny black surface
  - Produces grayish smoke and leaves residue in the barrel
  - Burns with reasonable rapidity when ignited

Ballistics

Velocity: the rate of speed of the bullet per unit of time, usually expressed in feet per second (ft/sec)
- Revolver: 600 ft/sec
- Pistol: 1,200 ft/sec
- Rifle: 2,500 ft/sec
- Shotgun: 3,300 ft/sec
F.Pull of Gravity: the downward reaction of the bullet towards the earth surface due to its weight
Air Resistance: the force of the air encountered by the bullet in its flight
Penetration: the entry of the bullet into the target
Ricochet: the bouncing of a projectile after hitting a surface

Exterior Ballistics

Ballistic Coefficient: describes the ability of a bullet to maintain its velocity against air resistance
Drift: the curve taken by the bullet while in flight
Gyroscopic Action: refers to the stillness of its rotating motion, attaining its highest momentum or stability in flight and penetrating power
Yaw: the unstable rotating motion of a bullet
Tumble: rotation of the bullet around the center
Wobble: the unsteady and uneven spin or rotation of a bullet, usually caused by insufficient twist in the rifle barrel
Keyhole Shot: the tumbling of the bullet in its flight, hitting the target sideways as a result of not spinning on its axis

Class Characteristics

Bore Diameter: the diameter of the bore, measured in hundredths or thousandths of an inch
Number of Lands and Grooves: the number of lands and grooves inside the barrel of a given firearm, always equal
Width of the Lands: dependent on the bore diameter, grooves, width, and number
Width of the Grooves: measured as the shortest distance between the two dies or edge of a groove
Direction of Twist: rifling inside the barrel of the gun is either twisted to the left or to the right, causing the bullet to rotate as it passes through the bore
Pitch of Rifling: the measure of the twisting of the lands and grooves, referring to the distance advanced by the rifling in order to make a complete turn inside the barrel

Explosives

Explosion: sudden breaking apart, shattering, or bursting in pieces by internal pressure
Detonation: resulting from practically instantaneous decomposition or combustion of unstable compounds
Explosive: any substance that may cause an explosion by its sudden decomposition or combustion
Low Explosives vs High Explosives: difference in explosion velocities, effects, and characteristics

Marks on Fired Bullets and Shells

Groove Marks: marks found on a fired bullet caused by the grooves of the barrel, same number as the landmarks
Skid Marks: marks found on fired bullets from a revolver, located at the anterior portion of the bullet
Stripping Marks: marks found on bullets fired from a "loose-fit" barrel
Shaving Marks: marks found on bullets fired from a revolver, caused by its forward movement to the barrel
Slippage Marks: marks found on fired bullets passing through an oily or oversize barrel
Marks found on fired shells:
- Firing Pin Mark: mark found at the base portion of the cartridge case, near the center of the primer cup
- Breech Face Mark: mark found at the base portion of the shell, caused by backward movement to the breech face of the block
- Extractor Mark: mark found at the extracting groove of the fired cartridge case, caused by its withdrawal from the chamber

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Description

Test your knowledge on bullet velocity, gravity pull, air resistance, penetration, and ricochet. Identify the correct velocities for revolver, pistol, rifle, and shotgun. Understand the impact of gravity and air resistance on bullet trajectory.

Bullet Velocity and Forces Quiz

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