BASIC OPERATION OF SMALL ARMS Flashcards
Ballistics
The science and study of the motion and impact of projectiles.
Three types of ballistics
Internal Ballistics
External Ballistics
Terminal Ballistics
Battle Sight
The range that allows you to hit the target between the throat and waist without sight adjustment.
Exact range veries with caliber of weapon.
Breechblock
A component that seals the breech and blocks gases from the fired cartridge.
Caliber
The distance across the bore of a weapon, measured from land to land expressed in hundredths of an inch.
Compensator
A device attached to the muzzle of a weapon designed to allow gases to be deflected upward through slots in the top surface of the compensator. The lower portion is solid, so while some gases escape from the top, gas is also pressing against the bottom. The pressure against the bottom pushes the compensator down, keeping the muzzle down. This tends to retarded muzzle climb.
Disconnector
Prevents the firing of more than one shot for one pull of the trigger or which prevents the weapon from being fired until the action is fully closed.
Flash Suppressor
A three or four pronged device attached to the muzzle of a weapon designed to cool the hot gases as it leaves the muzzle behind the round, cooling the gases reduces the flash.
Headspace
The distance from the breechblock to that part of the chamber which stops the forward movement of the cartridge case.
Muzzle Brake
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.
Sear
A component retained under spring tension that releases, by means of a trigger, either a firing pin, hammer, or bolt.
Types of Firing
Single Action (SA)
Double Action (DA)
Semi-Automatic (Semi-only)
Automatic (Auto-only)
Selective Fire (Sel.-fire)
Cycles of operation
Feeding Chambering Locking Firing Unlocking Extracting Ejecting Cocking
Feeding mechanisms
Magazines
Belts
Clips
Type of magazines
Box(inline or staggered)
Drum
Pan
Type of belts
SLD MLB
SLND MLB
FED MLB
FEND MLB
Type of clips
En-bloc clip
Stripper clips
Five types of cartridges
Rimmed cartridge Semi-rimmed cartridge Rimless cartridge Belted cartridge Rebated cartridge
5 varieties of firing pins
Free-floating Inertia Percussion Striker Fixed
The three ways firing pins receive their energy
- A larger mass strikes them. (Free-floating)
- A spring provides the energy. ( Inertia, percussion, striker)
- Their own mass provides the energy. ( Fixed)
Free-floating firing pin
Larger mass strikes the firing pin. Longer than its carrier; no spring is used on either forward or rearward movement of the firing pin.
Inertia firing pin
Forward energy is created when the hammer strikes the firing pin. As the pin is driven forward by the strike of the hammer, the spring compresses creating the energy needed to reset the firing pin.
Percussion firing pin
The firing pin is driven forward by the force of a compressed spring and is retracted by the cam action that cocks the weapon.
Striker firing pin
A firing pin which carried inside the blot and receives its forward momentum from its own spring, when activated by the trigger not struck by a hammer.
Fixed firing pin
It’s own mass provides the energy. A protrusion machined into the bolt/ breech which punctures the primer when the bolt has fully chambered the cartridge.
Two types of primers
Boxer: one flash hole. Has a cup shaped igniting system having the anvil and flash powder built in. (Reloadable)
Berdan: two flash holes. Contains only the flash powder, the anvil is part of the cartridge case and has two flash holes. (Non-reloadable)
8 locking systems
Rotating bolt Rising/ lowering bolt Swinging bolt Rising barrel Rotating barrel Rollers Locking block Locking flaps
Operating systems
Bolt action Blowback Delayed blowback Recoil Recoil with gas assist Gas operation Manual pump Revolving cylinder
Three types of gas systems
Gas blast
Gas tappet
Gas direct
Barrel
The portion of a weapon through which a projectile is propelled by the action of gases generated by the burning of propellent charge.
Beech
The outside rear face of the barrel which meets the face of the bolt or breechblock.
Components of a bullet
The bullet, powder, case and primer.
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 the engages the rim or extractor groove of the cartridge case while the cartridge is chambered. After firing the extractor withdraws the case from the chamber when the action opens.
Feed pawl
A hinged component of the feed mechanism designed for limited movement in one direction. This pawl acting through a lever engages succeeding cartridges in the feeding system and draws the cartridge into position for chambering.
Firing pin
The part of the firing mechanism that strikes or contacts the primer of the cartridge to cause ignition to fire the weapon.
Grooves
The portion of the rifling in a barrel that in conjunction with the lands imparts a spinning motion to a bullet.
Hammer
The component of the firing mechanism that imparts a sharp blow to the firing pin to initiate the primer.
Muzzle flaah
A incandescent flash in the air from the muzzle of the weapon which occurs when the bullet leaves the barrel. This flash is caused by the expansion of the emerging powder gases, ignition of oxygen in the air and expulsion of burning powder grains.
Rate of fire
The number of rounds which a weapon can fire in a minute, normally given in rounds per minute. RPM
Sustained ( normal fire rate)
Rapid ( trying to gain fire superiority)
Cyclic (combat emergencies, maximum RPM)
Primer
A small charge that is detonated by the firing pin which in turns ignites the powder or propellant charge in the cartridge.
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 breach to the muzzle.
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.
Military cartridge
Diameter of the bullet times the length of the cartridge case expressed in millimeters.
SA and DA
SA: weapon will only fire when it has been manually locked.
DA: Trigger bar will cock the weapon when the trigger is pulled and the sear will release the hammer.
