Chapters IV, V, and VI Flashcards
It is also known as shell or casing. It refers to the tabular casing or shell of an ammunitions that holds the bullet and contains the gunpowder.
Cartridge Case
Functions of Shell
- It houses the bullet, gunpowder and primer.
- It serves as waterproof container of gunpowder.
- It prevents escape of gases despite of pressure.
Standard cartridges of center-fire ammunitions have a shell that is usually made of ______ – ___________ and ________.
brass; 70% copper; 30% zinc
Anatomy of a Cartridge Case
- Rim
- Primer Pocket
- Vent or Flash Hole
- Body
- Neck
- Cannelure
- Crimp
- Shoulder
- Base
- Head stamp
- Extracting Groove
It is the part of the cartridge case that serves to limit the forward travel of cartridge into the chamber and the clearance between the head are supporting.
Rim
It has three functions: to hold the primer in central position, to prevent gas from escaping to the rear of the cartridge, and to provide solid support of primer anvil.
Primer Pocket
It is also called flash hole. This part provides a passage of heat and flame from the primer pocket towards the gunpowder chamber.
Vent or Flash Hole
It is the ‘cork’ that plugs the breech to prevent gas from escaping at the rear of the gun barrel.
Body
For bottleneck shaped cartridges, the cork includes the ___________ and the _______.
shoulder; neck
It is the part that is occupied by the bullet, which is true for rifle and machinegun cartridges.
Neck
It is composed of serrated grooves found at the interior surface of the neck which has a dual function: to serve as lubricant groove and to prevent the bullet from being pushed or pulled.
Cannelure
It acts as the lip since it is found at the periphery of the mouth of the cartridge case. It has also two functions: to aid in holding the bullet in place and to resist the initial forward motion of the bullet while the gunpowder undergoes combustion.
Crimp
It supports the neck of the shell which is true to rifle and machinegun cartridges.
Shoulder
It is the bottom part of the case that contains the primer, rim (shell head), and headstamp.
Base
It is the bottom surface of the shell that contains engraved data such as the manufacturer’s ID, caliber and year of manufacture.
Head Stamp
It is the circular groove near the base of the shell designed for automatic withdrawal after each firing.
Extracting Groove
Types of Crimp
- Stab or Ring Crimp
- Taper Crimp
- Roll Crimp
It is used to secure the bullet in the shell to avoid being moved or loosened from its gripped.
Crimp
It is used only on jacketed ammo that consists of dimples or grooves pressed into the mouth.
Stab or Ring Crimp
It is used in the cartridge with headspace on the cartridge case mouth with lead bullets.
Taper Crimp
It is located at the neck that is rolled into the groove of the bullet.
Roll Crimp
This may refer to the powder charge or the case design.
Magnum
Types of Shells according to Shape
- Straight Case
- Bottleneck Case
- Tapered Case
This description of shell is true to pistol and revolver ammunition. This is the casing of all rimmed-cartridges for revolvers and all center-fire pistol ammo that are now manufactured.
Straight Case
This description is always true to rifle ammunition. This is the casing of most modern center-fire rifle ammos. This is the type of shell that provided the greatest power capacity commensurate with over all case length.
Bottleneck Case
It is an obsolete type of case. It is very rare but presently being used in magnum jet cartridge of caliber .22 firearms.
Tapered Case
Marks on Shell
- Firing Pin Marks
- Breechface Marks
- Extractor Marks
- Ejector Marks
- Ejector Port Marks
- Shearing Marks (Secondary firing pin marks)
- Magazine Lip Marks
- Chamber Marks
- Pivotal Marks
It is found on the primer (particularly on the primer cup).
Firing Pin Marks
Glock Pistols have ____________ firing pin marks.
rectangular
It is found on the base of shell caused by the breechface.
Breechface Marks
It is found on the extracting groove.
Extractor Marks
It is located at the rim at the base of the shell fired from automatic Firearms.
Ejector Marks
These are found on the side of the rim, caused by the contact between the shell and ejection port of the firearm.
Ejector Port Marks
It is found on the primer near the firing pin mark. It is just a rebound or duplication of firing pin marks.
Shearing Marks (Secondary firing pin marks)
It is found on the body of shell that is caused by the irregularities inside the chamber.
Magazine Lip Marks
It is found on the body of the shell that is caused by the irregularities inside the chamber.
Chamber Marks
It is found on the base of rimmed type shell that is caused by break type revolver during loading.
Pivotal Marks
It is a metallic or non-metallic cylindrical projectile propelled from a firearm by means of the expansive force of gasses coming from burning gunpowder.
Bullet
In police parlance, the bullet maybe called _____. In governmental parlance, a cartridge containing bullet is called ________________.
slug; ball cartridge
_______ were the original terminology of all bullets.
Balls