Ammunition

Centerfire Ammunition

• Made of: bullet/projectile, gun powder/propellant, cartridge case, primer

• Bullets are typically made of lead and can be “jacketed” or covered with copper. Other materials can be used to make bullets such as zinc, brass, or alloys

Shotgun Ammunition

Made of: shotshell, shot, wadding

• Shotshell: can be made of plastic, paper, or metal

• Shot: typically lead or steel

• Wadding: plastic cup that holds the shot

  • Single projectile = slug

Rifle Ammunition

Bottleneck Cartridge

• A cartridge case having a main diameter and a distinct angular shoulder stepping down to a smaller diameter at the neck position of the case

• Designed to have a larger volume in the case to hold more gunpowder

Rimfire Ammunition

Has the priming compound around the circumference of the base instead of as a separate component

Full metal jacket

A projectile in which the bullet jacket encloses the entire bullet, with the usual exception of the base.

Jacketed Soft Point

A bullet designed with the soft lead core exposed at the nose.

Allows for the expansion of the bullet on impact

Cannelure

A circumferential groove generally of a knurled or plain appearance in a bullet or cartridge case.* Typically found on revolver and rifle bullets

Jacketed Hollow Point

A bullet designed with a jacket- typically copper- surrounding the lower portion. The nose of the bullet has a hollow point.

Allow for an easier expansion (mushrooming) when coming in to contact with an object. Increases the surface area of the bullet with the goal to get the bullet to stop after penetration.

Lead Round Nose

• An elongated projectile made of a lead alloy with a rounded nose.

• Typically used for target shooting.

Semi-Wadcutter

• A bullet designed with a truncated nose and sharp shoulder

• Used for target shooting. The sharp shoulder on the bullet produces a clean round hole in paper.

Wadcutter

A cylindrical bullet design having a sharp shouldered nose intended to cut target paper cleanly to facilitate easy and accurate scoring.

Boat Tail

• A specific design of bullet having a tapered or a truncated conical base.* 

• The tapered cone of the boat tail provides increased stability throughout it’s flight

Types of firearm action

• Gas operated semiautomatic

• Lever action

• Pump action

• Bolt action

• Break action

• Delayed locking

Surface roughness

irregularity of the surface due to metal cutting

Chip formation

chips of removed material or swarf

Built-up edge

accumulation of material on the surface of the cutting tool

Plowing

piece of built-up edge is displaced into the workpiece; doesn’t form a chip. No loss of material, it is forced into the workpiece

Sideflow

plastic deformation of workpiece material displaced to the side of the area being cut

Shearing

complete removal of the metal being cut and extracted from the surface

Chatter

interrupted machining of metal

Pressure weld

metallic bond between contact of two metals caused by friction

What is the cycle of fire?

• Feeding

• Chambering

• Locking

• Firing

• Obturation

• Unlocking

• Extraction

• Ejection

• Cocking

Feeding

Inserting cartridges into the chamber. Breech bolt pushes the cartridge into the final position.

Chambering

Inserting the cartridges into the chamber, and having them be held in place

Locking

Locks the cartridge into the barrel before firing

Firing

When the breech is fully locked, a pull on the trigger mechanically translates to the firing pin release.

Obturation

Occurs when powder gases under high pressure are sealed to prevent them from jetting between primer cup and cartridge case, cartridge case and primer wall, and projectile and bore.

Unlocking

This is the reverse of the locking process and is frequently performed in conjunction with extraction.

Extraction

All cartridge cases are designed with a rim or groove (cannelure) at the base so that an extractor claw can grasp this edge in order to achieve extraction.

Ejection

In the final stages of extraction, the cartridge case encounters a projection that is usually at right angles to the exit portal of the breech. Rotating on the fulcrum of the extractor, the case base is contacted on the opposite side by the ejector, which flips the case out of the actuating mechanism.

Cocking

The hammer spring is usually cocked when the bolt of a rifle, pistol, or repeater shotgun is retracted.

Broach cutting

A tool having a series of cutting edges of slightly increasing height used to cut the spiral grooves in a barrel. All grooves are cut with a single pass of the broach.

Button Rifling

A hardened metal plug with a rifled cross section configuration. It is pushed or pulled through a drilled and reamed barrel so as to cold form the spiral grooves to the desired depth and twist.

Hammer Forging

An internal mandrel with rifling configuration which forms rifling in the barrel by means of external hammering