Built for dependable cycling and hard use, the ROSCO 556NATO/300BLK BCG PHOS BLK is a complete bolt carrier group for MIL-SPEC AR-15 platforms chambered in 5.56 NATO or .300 Blackout. Its full-auto-profile carrier and durable materials make it a reliable choice for new builds, replacement parts, and upgrades. Choose this versatile Rosco bolt carrier group for consistent function across a broad range of compatible setups.
Made to MIL-SPEC standards, the carrier is constructed from 8620 steel and paired with a 9310 steel bolt that is magnetic-particle inspected (MPI) and shot-peened for added strength and stress resistance. A time-tested exterior phosphate finish helps resist corrosion, while the chrome-lined interior supports smooth operation and extended service life. The properly staked gas key helps maintain secure assembly through repeated use, and the BCG arrives fully assembled with its firing pin, cam pin, and retaining pin.
- Complete bolt carrier group for 5.56 NATO and .300 Blackout
- Full-auto-profile carrier made from durable 8620 steel
- 9310 steel bolt, MPI inspected and shot-peened
- Black phosphate exterior finish for corrosion resistance
- Chrome-lined interior for smooth operation and durability
- Properly staked gas key for dependable assembly
- Includes firing pin, cam pin, and retaining pin
- Fully assembled and ready to install in a MIL-SPEC AR-15 upper
For shooters seeking a rugged AR-15 bolt carrier group with flexible 5.56 NATO and .300 BLK compatibility, the ROSCO 556NATO/300BLK BCG PHOS BLK delivers proven construction and practical versatility. Add this dependable component to your compatible rifle build or keep it on hand as a quality replacement.
