What is a AR-15 Bolt Carrier Group?

At the heart of every AR 15 is a bolt carrier group. The bolt carrier group
sits in the center of the rifle, in front of the stock, above the magazine, and behind the barrel. It's inside the rifle and is incredibly important to the weapon's function. Like everything in the AR-15 world bolt carrier groups is varied depending on the user's budget, caliber, and build intentions. That might answer your question about what a AR-15 bolt carrier group is, but if not, keep reading because we are diving deep into the world of the BCG
.

Toolcraft Black Nitride .223/5.56 BCG

What the BCG Does

Bolt Carrier Groups
do a lot inside your rifle. The best way to understand them is to examine them through the firing process. First and foremost, the hammer is released when the user pulls the trigger. The hammer strikes the firing pin, which is a component of the BCG. The firing pin strikes the primer of the round and the round fires. As the burning gas goes down the barrel, some are siphoned off down a gas tube. That gas meets the BCG's gas key, which then pushes the BCG back like a screaming eagle. It flings rearward, and as it flings rearward, the BCG ejects the spent casing and resets the hammer. The BCG moves backward against the buffer until the spring compresses. The spring propels the buffer and BCG forward once more, and the BCG then picks up the next round in the magazine and pushes it into the chamber. Now the weapon is ready to fire once more. For the Bolt Carrier Group to do all of this, it has to be made of multiple components.

FosTecH Complete M16/AR-15 Black Nitride BCG

Bolt Carrier Group Components

The Group in Bolt Carrier Group is placed there for a reason. BCG's have nine components: Bolt Carrier Bolt Assembly Bolt Head Firing Pin Firing Pin Retainer Pin Extractor Gas Rings Gas Key Cam Pin The combination of these different parts and pieces show the genius of Eugene Stoner and his design. The combination of parts and pieces in one carrier makes the rifle easier to clean, assemble, and it also makes repairs an absolute breeze. The AR-15 bolt carrier group is very simple to take apart, and you can make minor repairs in just minutes.

FosTecH Complete M16/AR-15 Nickel Boron Low Mass BCG

Bolt Carrier Groups Vary

Bolt carrier groups vary in mainly three different ways. The first is their finish. Different finishes can reduce wear, as well as increase reliability when the bolt is incredibly dirty. Different finishes also make it easier to clean a BCG. The second way they vary is in weight. Lightweight bolt carrier groups are often used to build rifles designed to have very minimal recoil. When paired with the right ammo and an adjustable gas tube and proper buffer weight, you can tune down the gas required to cycle the bolt, and therefore reduce recoil. Bolt carrier groups can also vary in caliber. 9mm blowback bolts are, for example, a bit different than your standard AR-15 BCG. While BCGs may vary, they are always present in one way or another in an AR-type rifle. They are critical portions of any AR-15 rifle, so it's a component you should take time in selecting and not cheap out on. Give our selection a look over and know that we only provide quality BCGs for all your rifle-building needs. Shop All Bolt Carrier Groups
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