Base Ops Exam Prep Flashcards by Mike B

List the feeding mechanisms

Magazine,
Belts,
Clips

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List the varieties of firing pins

Free-floating,
Inertia,
Percussion,
Striker,
Fixed

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Define breech

outside rear face of the barrel which meets the face of the bolt

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Define Sear

component retained under spring tension that releases, by means of a trigger, either a firing pin, hammer, or bolt

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Define Trigger

finger actuated lever used to activate firing mechanism, when pulled, fires the weapon

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Define Trigger Bar

Merely an extension of the trigger, connecting bar operating between the trigger and sear

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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.

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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)

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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

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List the cycles of operation

Feeding,
Locking,
Chambering,
Firing,
Unlocking,
Extracting,
Ejecting,
Cocking

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Define Muzzle Velocity

measured in ft/sec at which the bullet leaves the barrel

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List the types of primers

Boxer and Berdan

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Define Ejector

a projection in receiver in which cartridge case is pressed against and thrown out of mechanism after extractor pulls it from chamber

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List the types of ballistics

Internal, External, Terminal

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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

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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 ```