AR-15 .223/5.56/300BLK Nickel Boron Bolt Carrier Group

Upgrade your rifle with the A1Armory .223/5.56/300BLK M16 Nickel Boron Bolt Carrier Group, designed for peak reliability, smoother cycling, and simplified maintenance. Engineered to exceed MIL-SPEC standards, this complete BCG offers top-tier performance for .223 Remington, 5.56 NATO, and .300 AAC Blackout platforms.

Every component is crafted in the USA and finished with UCT EXO Nickel Boron Coating, delivering unmatched lubricity, superior wear resistance, and effortless carbon cleaning. Whether you're building a new rifle or upgrading your current setup, this BCG is built to perform under pressure.

✅ Key Features:

✅ Premium UCT EXO Nickel Boron Coating

• Provides exceptional lubricity and wear resistance

• Reduces friction and eases carbon removal during cleaning

✅ 8620 Steel M16 Profile Carrier

• Heat-treated, shot peened, and relief cut

• Machined to precise MIL-SPEC dimensions for flawless function

✅ Carpenter 158 Steel Bolt (.223/5.56/.300BLK)

• Heat-treated, shot peened, and Nickel Boron coated

• Trusted durability and consistent performance

✅ 4140 Billet Gas Key

• Nickel Boron coated and staked with Grade 8 fasteners

• Secure, leak-free gas seal for maximum reliability

✅ 4140 Precision Cam Pin

• Heat-treated, ground to tight tolerances, and Nickel Boron coated

• Engineered for longevity under repeated use

✅ Billet 4140 Extractor

• Heat-treated and shot peened

• Phosphate-coated for dependable case extraction

✅ 17-4 H900 Stainless Steel Firing Pin

• Precision machined for smooth cycling and corrosion resistance

✅ Compatible with .223, 5.56 NATO, and .300 AAC Blackout

• Multi-caliber versatility in one robust, high-performance assembly

✅ 100% Made in the USA

• Proudly manufactured to the highest standards of American craftsmanship

Optimize your AR platform’s performance and reliability with the A1Armory Nickel Boron BCG—trusted by professionals, competitors, and discerning builders alike.