What is a Bolt Carrier Group?
The Bolt Carrier Group (BCG) is the quintessential component in the rifle’s assembly, which is responsible for loading rounds into the chamber, firing those rounds, extracting and ejecting the spent casings, and operating the hammer to repeat the firing process. This component is subject to extreme pressure and high temperatures, so choosing a BCG that’s produced using the highest quality materials and innovative design is important in ensuring your AR-15 not only performs with precision in high-pressure situations but also continues functioning reliably for many years to come.
Building your own AR-15 or similar rifle involves learning about the function of each group of components. Serving as the heart of your rifle is the bolt carrier group. The bolt carrier group is comprised of multiple parts and is essential to your rifle assembly, as it allows the completion of a full cycle when you shoot. Choosing a bolt carrier for your build means deciding between several finishes, calibers, and colors. Matrix Arms makes your decision easier by offering a high-quality assembled 5.56 bolt carrier group as well as individual components for your purchase.
One of the key benefits of the AR-15 platform is the ability to change calibers by simply swapping a complete upper assembly or by replacing the individual components—the bolt, barrel, and upper or lower receiver. Matrix Arms’s 5.56 Bolt Carrier Group will allow you to optimize your AR-15 Bolt Carrier Group for use with 5.56 NATO rounds.
Bolt Carrier Group Purpose
The bolt carrier group, when properly assembled and added to your AR-15, rapidly completes a series of steps that activates when the trigger is pulled. First, the firing pin is activated and strikes the chambered round primer. The round fires and the spent shell casing are ejected from the rifle. The hammer is re-cocked, and a new round is removed from the magazine and placed in the chamber to fire. This full-cycle process all takes place due to the proper assembly of the bolt carrier group.
AR-15 Bolt Carrier Group Components
When building a rifle, you can purchase a fully assembled AR-15 Bolt Carrier Group, or you can choose to assemble one on your own by purchasing and assembling the individual components.
The Bolt Carrier Group consists of several key components:
- BOLT CARRIER — Serves as the housing for the carrier key, bolt and extractor unit, gas ring, and the firing, retaining, and cam pins.
- BOLT CARRIER GAS KEY — Fits over the end of the gas tube and helps modulate the pressurized gases traveling within, which is necessary for cycling the rifle’s action.
- BOLT and EXTRACTOR UNIT — These components work in unison to lock and unlock as a round is fired so another round can be pulled from the attached magazine.
- GAS RING — This component channels the gas toward the bolt instead of allowing it to escape into the upper receiver.
- FIRING PIN, RETAINING PIN, and CAM PINS — These pins allow the Bolt Carrier Group’s other components to perform their respective functions properly without over-rotating or falling out of the assembly.
Purchase Your Bolt Carrier Group
Find your ideal 5.56 Bolt Carrier Group or choose from a variety of components by contacting Matrix Arms for full inventory options.