Just the Basics – the AR-15 Carbine

 

An introduction of a basic AR-15 Carbine.

The component group that consists of the Barrel, Handguard and the Bolt Carrier Group is the “Upper Receiver”. The component group that consists of the Stock, the Grip, Trigger Assembly and Magazine Well is the “Lower Receiver”. This is the component that is registered with the AFT as a “Firearm” when your weapon is registered.

The Barrel is the component that allows the bullet to exit the carbine after it is fired and adds a spin to the bullet to increase its accuracy.

The Muzzle is the region immediately at the end of the Barrel where the bullet exits.

The Front Sight, used in conjunction with the Rear Sight is used to acquire an accurate sight picture prior to engaging a threat.

The Bolt Carrier Group consists of the Bolt, the Extractor and the Firing Pin. In a gas powered carbine, a portion of the gas expelled by firing the cartridge is fed back down into a port on the front of the Bolt Carrier Group. The bolt is driven back – ejecting the spent casing and then stripping a new cartridge off the top of the Magazine and driving it into the chamber. This also charges the firing pin for firing when the Trigger is pressed to the rear. In a piston driven carbine a portion of the gas expelled by firing the cartridge is used to drive a piston rearward. This then drives the bolt back – ejecting the spent casing and then stripping a new cartridge off the top of the Magazine and driving it into the chamber. This also charges the firing pin for firing when the Trigger is pressed to the rear.

In the event that the Bolt Carrier Group fails to fully seat forward, the Forward Assist can be slapped with a palm to fully seat the Bolt Carrier Group.

The Charging Handle can be used to manually eject a spent casing or a malfunctioning round. Once released, the Bolt Carrier Group will fly forward normally.

The Ejection Port is the location that spent casings are ejection from on the Upper Receiver. The Ejection Port Cover is provided to protect the chamber from dust and debris when the weapon is not being fired.

The Magazine Release is pressed inward to release the Magazine from the Lower Receiver.

The Bolt Release (sometimes called the “Ping Pong Paddle”) is activated by pressing on the “paddle”. This releases the Bolt Carrier Group and allows it to fly forward stripping a new cartridge from the Magazine and seating it in the chamber.

The Fire Selector switch the weapon between Safe and Fire in civilian models. A Burst or Auto position is added to military and some law enforcement models.

The Magazine contains the cartridges to be fired and feeds a new cartridge into chamber each time the weapon if fired – until the magazine is empty.

The Magazine Release is used to drop an empty magazine from the Magazine Well in order to make room for a replacement magazine that is fully loaded.

The Grip is the portion of the Lower Receiver that is actually “gripped” by the shooter.

The Trigger is the component that is pressed to the rear releasing the Firing Pin contained in the Bolt Carrier Group and firing the cartridge.

The Trigger Guard provides protection against an accidental discharge from rubbing the Trigger against something unexpected.

The AR-15 Carbine is loaded by inserting a loaded Magazine into the Magazine Well and seating it with a firm palm-slap to the bottom of the Magazine. The shooter than manually racks the Charging Handle to the rear and releases it or depresses the paddle on the Bolt Release. This will strip a new cartridge out of the Magazine and load it into the chamber at the rear of the Barrel. From this point forward, each time the weapon is fired, part of the energy is captured to automatically force the Bolt Carrier Group to the rear, eject the spent cartridge out of the Ejection Port and to strip a new cartridge from the Magazine and load it into the chamber at the rear of the Barrel. This process will continue each time the Trigger is pressed until the Magazine is empty.

Unloading can be done by depressing the Magazine Release and capturing the Magazine as it falls from the Magazine Well. To display that the weapon is empty, rack the Charging Handle to the rear ejecting any un-fired cartridge that may still be in the chamber out of the Ejection Port. Push the “handle” of the Bolt Carrier Release down locking the bolt to the rear. This allows the shooter to easily verify the weapon is, indeed, empty.

The Stock on most modern AR-15 Carbines is adjustable to establish a proper fit to the shooter for the mission and environment at hand. Also located on the Stock are multiple Sling Points used to attach a portion of a weapon sling to carry the weapon easily on the shooter’s body. A Sling (in this case a “Two Point” Sling) is used to hang the weapon from the shooter’s body. This allows them free hands to deal with whatever situation is before them.

The Handguard is used to protect the shooters support hand from the massive barrel heat that is generated by firing the weapon as he grasps the weapon. The image shows a Handguard that is also a “Quad Rail” Picatinny Rail mounting system. These rails can be used to mount Forward Grips, Sling Points, Lights, Laser Targeting Systems as well as a host of additional attachments.

What is the difference between a “Carbine” and a “Rifle”? Well, it depends on the time period you are looking at. Carbines began to come into their own towards the end of the Civil War. Traditional battlefield rifles were very unwieldy for mounted troops. Heavy, difficult to load, long – it was not a good mix. The advent of the lever action rifle began during the latter half of the war. Still, these “long guns”, while easier to load – were still difficult to handle. Enter the carbine – shorter, firing the same cartridge as the sidearm that was carried they became the staple of the Mounted Calvary. The most famous were the generations of Winchester Lever Action Carbines. And that is what depicted a carbine of that time period – a light rifle that fired the same cartridge as the sidearm the shooter carried.

World War I saw heavy use of bolt-action battlefield rifles and the introduction of the modern day machine gun – little changed in the carbine arena. Fast forward to World War II and the introduction of Garand’s battlefield rifle. Top loaded, rapid firing, exceptionally accurate - yet it was still heavy, bulky and slower to load than was desired. Enter the modern evolution of the battlefield carbine – the M1 carbine. Shorter barrel, loaded by a bottom-fed magazine and significantly lighter. This was the “pattern” established in the military that is carried forward to today.

Vietnam saw the introduction of the M-16 battlefield rifle. This was compressed into the KAR-16 and finally into today’s version – the M4 Carbine.

So, generally, a carbine fires the same cartridge as a full-sized battlefield rifle but comes with a shorter barrel, it’s lighter, usually has an adjustable stock and it’s equipped with the ability for equipment “add-ons”. A smaller, more compact weapon is much easier to handle in both urban and a wide range of field environments and has become a favorite of military organizations worldwide.