AR-15 Bolt Carrier Group (BCG): How it Works, Maintenance and How to Buy
The AR-15 bolt carrier group, or BCG, is a critical and often misunderstood piece of the AR-15/M16 upper receiver. Here I will give a brief breakdown of the BCG’s components, how it works, problems to look for and what to consider when buying. The image below gives a nice breakdown of the parts in a typical BCG. We won’t get … Read more