Firearm Competency Ammunition Types and Ballistics 2 — Questions and Answers
Question 1: What is meant by 'muzzle velocity' in ballistics?
- The speed at which the trigger is pulled
- The speed of the bullet at the moment it exits the barrel (Correct answer)
- The rotational speed of the bullet in flight
- The velocity of escaping gas from the ejection port
Correct answer: The speed of the bullet at the moment it exits the barrel
Muzzle velocity is the speed of the bullet as it leaves the muzzle of the firearm, typically measured in metres per second (m/s) or feet per second (fps).
Question 2: What is the key difference between rimfire and centrefire cartridges?
- Rimfire cartridges are larger than centrefire cartridges
- The primer location: rimfire has primer in the rim, centrefire has primer in the centre of the base (Correct answer)
- Centrefire cartridges cannot be reloaded, but rimfire cartridges can
- Rimfire cartridges use smokeless powder while centrefire uses black powder
Correct answer: The primer location: rimfire has primer in the rim, centrefire has primer in the centre of the base
In rimfire cartridges the primer compound is contained within the hollow rim of the case, whereas centrefire cartridges have a separate, replaceable primer in the centre of the base.
Question 3: What does a '+P' marking on a box of ammunition indicate?
- The ammunition is suitable for pistols only
- The ammunition has a positive rifling twist
- The ammunition is loaded to higher-than-standard pressure (Correct answer)
- The ammunition has a polymer-tipped bullet
Correct answer: The ammunition is loaded to higher-than-standard pressure
+P indicates overpressure ammunition loaded to higher chamber pressures than standard, which increases velocity but should only be used in firearms rated for it.
Question 4: What unit is commonly used to express bullet weight in ammunition specifications?
- Grams
- Grains (Correct answer)
- Milligrams
- Ounces
Correct answer: Grains
Bullet weight is conventionally measured in grains (gr), where one grain equals approximately 0.0648 grams, allowing for precise specification of bullet mass.
Question 5: What is a soft point (SP) bullet designed to do compared to a full metal jacket?
- Travel faster due to reduced friction
- Expand upon impact while retaining more mass than a hollow point (Correct answer)
- Penetrate armour more effectively
- Reduce muzzle flash when fired
Correct answer: Expand upon impact while retaining more mass than a hollow point
A soft point bullet has an exposed lead tip that causes controlled expansion on impact, making it suitable for hunting as it transfers energy efficiently while retaining mass.
Question 6: Under the South African Firearms Control Act, which category of ammunition is prohibited from civilian possession without specific authorisation?
- Hollow point pistol ammunition
- Rimfire .22 LR ammunition
- Armour-piercing ammunition (Correct answer)
- Shotgun slug ammunition
Correct answer: Armour-piercing ammunition
Armour-piercing ammunition is prohibited for civilian possession under Schedule 2 of the Firearms Control Act unless a specific permit is granted.
Question 7: What does the term 'bore' refer to when describing a firearm barrel?
- The external diameter of the barrel
- The interior channel of the barrel through which the bullet travels (Correct answer)
- The thickness of the barrel walls
- The length of the barrel measured in calibres
Correct answer: The interior channel of the barrel through which the bullet travels
The bore is the internal channel of the barrel, and its diameter determines the calibre; the bore is also where rifling grooves are cut to stabilise the bullet.
Firearm Competency Ammunition Types and Ballistics 2
What is meant by 'muzzle velocity' in ballistics?