AR-15 Complete Upper with BCG: Why a Bolt Carrier Group Matters Building an AR-15 from the ground up can be rewarding, but for many AR owners, choosing an AR-15 complete upper—particularly one with a high-quality bolt carrier group (BCG) – offers immediate benefits in convenience, performance, and reliability. With a complete upper, you skip the … Continue reading AR-15 Complete Upper with BCG: Why a Bolt Carrier Group Matters