Small arms terminology Flashcards
What are the three types of ballistics?
- Internal
- External
- Terminal
Breechblock
A component that seals the breech and blocks gases from the fired cartridge. (Bolts in rifles, slides in pistols).
Disconnector
A device which prevents the firing of more than one round for one pull of the trigger OR prevents the weapon from being fired until the action is fully closed (in battery).
Ejector
A cam or projection inside the receiver against which the cartridge case strikes and is thrown clear of the mechanism after it has been drawn from the chamber by the extractor.
Extractor
A component that engages the rim or extractor groove of the cartridge case while the cartridge is in the chamber. After firing the extractor withdraws the case from the chamber when the action opens.
Fluted chamber
Leaves linear burn marks on spent cartridge cases produced by the gases that cycle the weapon. Gases fill grooves in chamber, allowing for easier extraction of the spent cartridge case.
Firing pin
The part of the firing mechanism that strikes or contacts the primer of the cartridge to cause ignition to fire the weapon.
Headspace
The distance from the breechblock to the part of the chamber which stops the forward movement of the CARTRIDGE CASE.
Muzzle break
A device at the muzzle end of the weapon which deflects the emerging powder gases. The energy imparted by this act of deflection pulls the weapon FORWARD to offset some of the rearward motion of recoil.
Rifling
A series of spiral grooves in the bore of a barrel which imparts a spinning motion to the bullet as it travels the length of the barrel from the breech to the muzzle. Stabilizes the projectile in-flight.
What are the five methods for creating rifling?
- Cut rifling
- Broached
- Button
- Hammer forging
- Flow forming
What are the two profiles for rifling?
- Lands and grooves
2. Polygonal
Sear
A component retained under spring tension that releases, by means of a trigger, either a firing pin, hammer, or bolt.
Trigger
A finger actuated lever used to activate the firing mechanism, firing the weapon.
Trigger bar
A connecting bar operating between the trigger and the sear. Nothing more than an extension of the trigger.
Single action (SA)
Requires manual cocking (e.g. slide or hammer pulled rearward)
Double action (DA)
The trigger bar cocks the weapon when the trigger is pulled and the sear releases the hammer when the trigger has reached maximum rearward movement.
What are the five types of firing?
- Single action (SA)
- Double action (DA)
- Semi-automatic only (semi-only)
- Automatic-only (auto-only)
- Selective fire (sel.-fire)
Trajectory
The path the bullet takes from the muzzle of the weapon to the target. The bullet immediately begins to drop upon exiting the muzzle of the weapon due to atmospheric resistance and gravity.
What are the two types of sights?
- Fixed
2. Adjustable
How does the US military measure rounds?
By taking the diameter of the bullet by the length of the cartridge case, in millimeters (e.g. 7.62 x 51mm).
How does the civilian sector measure rounds?
Caliber calculated by taking the distance across the bore of the weapon, measured from land-to-land, expressed in hundredths of an inch.
What are the three parts of trajectory?
- Rising branch
- Maximum ordinate
- Falling branch
What is a battle sight?
The range that allows the shooter to hit a target between the throat and waist without a sight adjustment. Exact range varies with weapon and caliber.
Flash suppressor
A three or four pronged device attached to the muzzle of a weapon, designed to cool the hot gases as they leave the muzzle behind the round; cooling gases reduces the muzzle flash.
Choke
Constriction at the muzzle end of the barrel that condenses the shot pattern to increase the max effective range.
Ballistics
The science and study of the motion and impact of projectiles.