1. Firearms and Cartridges
BALLISTICS
Firearms and Cartridges

2. Terms Ballistics: the study of bullets and firearms
Firearms: a weapon capable of firing a projectile using a confined explosive

3. History
Gunpowder was invented by the Chinese more than 1,000 years ago
It is a combination of potassium nitrate, charcoal, and sulfur that expands to 6x its size when ignited
The first guns were developed in Europe during the 14th century

4. Early Weapons Matchlock:
These weapons had wicks to carry a flame to the gunpowder
These weapons were muzzle-loaders
The powder and projectile were put down the firearm’s barrel (muzzle) and packed into place

5. Early Weapons (cont.) Flintlock:
These weapons used sparks from a chip of flint to ignite the gunpowder
These weapons were muzzle-loaders

6. Percussion Firing Replaced the flintlock method of firing
Started with the introduction of a cartridge, which is a case that holds a bullet, a small amount of primer powder, and the gunpowder
A hammer hits the primer powder, which explodes to ignite the gunpowder
Cartridges are loaded opposite the barrel (breech) so these weapons are called breech-loaders

7. Semiautomatic vs. Fully automatic
A semiautomatic fires only one bullet per pull of the trigger
A fully automatic fires repeatedly as long as the trigger is pressed
In both weapons, the empty cartridge ejects and the next cartridge advances automatically

8. Hand Guns
Designed to be fired with one hand and are called pistols; classified into:
Revolvers--Hold 6 cartridges in a cylinder that turns as the weapon is fired
Semiautomatic Pistols

9. Single vs Double Action Revolvers
Single Action revolvers require cocking the hammer and pulling the trigger to release the hammer
In Double Action revolvers the trigger cocks the hammer and causes it release

10. Semiautomatic Pistol
Hold up to 10 cartridges in a magazine (a.k.a. clip), which is locked into the grip of the firearm

11. Long Guns Require the use of two hands for accurate firing; include:
Rifles—fire bullets
Shotguns—fire either small round pellets (shot) or a single projectile (slug)

12. Rifles
Bolt Action: manually loaded and unloaded by rotating a bolt into position
Lever Action: manually loaded and unloaded by an external lever

13. Shotgun
Pump Action: features a movable forearm which is manually actuated in motion parallel to the barrel by the shooter

14. Rifling
To increase the accuracy of a shot, a projectile should have a twist
The barrel of a weapon has raised areas (lands) and indentations (grooves) that cause the bullet to spiral as it exits

15. Rifling (cont.)
Rifling refers to the pattern left on a bullet by the lands and grooves
Because it is impossible to produce two identically rifled gun barrels, a bullet can be matched to the specific gun from which it was fired

16. Cartridge A typical cartridge contains: Bullet Primer powder Gunpowder
Casing material
Anvil and flash hole: which delivers the explosive charge from the primer to the gunpowder
Headstamp: identifies the caliber and manufacturer

17. Caliber Bullets and their cartridges are named by caliber and length
The caliber is a measure of the diameter of the cartridge measured in hundredths of an inch
Common calibers include .22, .25, .357, .44 and .45

18. Caliber (cont.) Sometimes calibers can be measured in mm
Caliber also refers to the diameter of the inside of a firearm’s barrel
The caliber of ammunition should match the firearm that shoots it

19. How a Firearm Works
The tiny explosion causes the anvil to deliver a spark to the main gunpowder supply
The firing pin hits the base of the cartridge and ignites the primer powder
Pull the trigger

20. How a Firearm Works (cont.)
The gunpowder ignites and the explosion pushes the bullet from the casing and into the barrel where it follows the lands and grooves pattern and begins its spiral before it exits