Base Ops Exam Prep Flashcards
List the feeding mechanisms
Magazine,
Belts,
Clips
List the varieties of firing pins
Free-floating, Inertia, Percussion, Striker, Fixed
Define breech
outside rear face of the barrel which meets the face of the bolt
Define Sear
component retained under spring tension that releases, by means of a trigger, either a firing pin, hammer, or bolt
Define Trigger
finger actuated lever used to activate firing mechanism, when pulled, fires the weapon
Define Trigger Bar
Merely an extension of the trigger, connecting bar operating between the trigger and sear
Describe the types of primers
Boxer: one flash hole, built in igniting system which has the anvil and powder built in.
Berdan: two flash holes, contains only the flash powder. The anvil is part of the cartridge case therefore non-re-loadable.
What three ways to firing pins receive their energy?
A larger mass striking them (free-floating),
A spring providing the energy (inertia, percussion, striker)
Their own mass provides the energy (fixed)
Define Feed Pawl
hinged component of feeding mechanism designed for limited movement in 1 direction. This pawl acting through a lever, engages succeeding cartridges in feeding system and draws cartridges into position for chambering
List the cycles of operation
Feeding, Locking, Chambering, Firing, Unlocking, Extracting, Ejecting, Cocking
Define Muzzle Velocity
measured in ft/sec at which the bullet leaves the barrel
List the types of primers
Boxer and Berdan
Define Ejector
a projection in receiver in which cartridge case is pressed against and thrown out of mechanism after extractor pulls it from chamber
List the types of ballistics
Internal, External, Terminal
List the operating systems
Bolt Action, Blowback, (UZI) Delayed Blowback, (MP5,G-3) Recoil, (M9, M1911, M2HB) Recoil with gas assist, (MG3) Gas operation (Gas Blast (240B), Gas Tappet (SCAR), Gas Direct (M16)), Manual Pump, Revolving Cylinder
What are the components of a bullet
Cartridge, Primer, Cartridge Case, Powder
Define Disconnector
device on a weapon preventing firing of more than 1 shot per 1 pull of the trigger, prevents firing until action is fully closed
Define Muzzle Flash
Incandescent flash in air at the muzzle which occurs when the bullet leaves barrel. Caused by expansion of gases, ignition of oxygen in air, and expulsion of burning powder gases.
List the magazine types
Box (Staggered/In-line),
Drum,
Pan
Define barrel
portion of the weapon which projectile propelled by action of gases generated by burning propellant charge
Describe Free-Floating Firing Pin
Larger mass strikes firing pin. Longer than its carrier, no spring used on forward or rearward movement of firing pin (M1, M14, M16, AK)
Define ballistics
The science and study of the motion and impact of projectiles
Define battle sight
the range at which the target is hit between the throat and waist without sight adjustment
Define breechblock
component that seals the breech and blocks gases from fired cartridge (Gives direction to gases)
Define Headspace
the distance from breechblock to the part of chamber which stops forward movement of cartridge case
Describe 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 (M60, M2HB)
List the types of cartridges
Rimmed, Semi-Rimmed, Rimless, Belt, Rebated
Describe 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, spring compresses creating the energy needed to reset firing pin (1911, USP)
Define Extractor
Component that engages extractor groove of the cartridge case while in the chamber. After firing, extractor withdraws case from chamber when action opens
Describe Fixed Firing Pin
Its own mass provides the energy. A protrusion machined into the face of the bolt/breech which punctures the primer when the bolt has fully chambered the cartridge. Found in most blowback operated machine guns. (UZI)
Define Rifling
Series of spiral grooves in bore of barrel which imparts a spinning motion to bullet as it leaves the barrel from breech to muzzle
Define Muzzle Brake
device at end of muzzle which deflects emerging powder gases. Energy imparted pulls weapon forward to offset rearward recoil
Define Firing Pin
part of firing mechanism that strikes primer of cartridge to cause ignition to fire the weapon
Describe Striker Firing Pin
A firing pin which is carried inside the bolt and receives its forward momentum from its own spring, when activated by the trigger, not struck by the hammer. A squeeze cocking system is what compresses the firing pin (P7)
Define Primer
small charge detonated by firing pin, which ignites powder of propelling charge in cartridge
Define Compensator
device attached to muzzle allowing gases to be deflected upward through the top slots. Lower portion is solid causing gases to push muzzle down, retarding muzzle climb
Define Flash Suppressor
3 or 4 pronged device attached to the muzzle designed to cool hot gases as they leave the muzzle behind the round, reducing the flash
List the locking systems
Rotating Bolt (M4, M249) Rising/Lowering Bolt (M240B, FN/FAL) Roller (MG3, G3, MP5) Rising Barrel (1911) Locking Flaps (Dshk) Swinging Bolt (SGM) Locking Block (M2HB, M9) Rotating Barrel
