Rosco Manufacturing Bolt Carrier Group (Phosphate Coated and Chrome Lined) – 5.56 / 300 BLK


In stock

SKU: ROS-BCG-002 UPC: 181969500838

Product Description

These 5.56 / 300 BLK Bolt Carrier Groups are Phosphate Coated with Chrome Lined Gas Key & Bolt Channel, Full-Auto rated, properly staked, and the bolts are Matched to the barrel. Our Rosco Phosphate Bolt Carrier Groups are designed to meet the modern-day carbine shooters’ requirements.

For our Phosphate Bolt Carrier Groups – we choose to team up with the best – Microbest, so the end-user has dependability time after time, every time.

We have also balanced input from our consumers and military end users in order to bring you the product you need, not just the one we want to sell you.

These BCGs are to MIL Specification and have a properly staked gas key along with a chrome-lined coating for extended performance. They also feature a Shot Peened/ MP tested Matched bolt (with an upgraded extractor) which is designed to lock up perfectly with our extensions for extreme accuracy. These BCGs are made to withstand Full-Auto rated fire and unforgiving use from the end user.

  • Carrier Material: 8620 Steel
  • Gas Key: 4130 Steel, attached with Grade 8 hardware, properly staked
  • Cam Pin: Hardened 4340 Steel
  • Firing Pin: 8740 Steel, Heat Treated, Mil-Spec, Center-less ground, Hard Chrome Plated
  • Bolt Material: C158, Phosphate Coated, MPI/HPT
  • Extractor: 4140 Steel, Heat Treated, Shot Peened
  • Ejector: S2-S7 Tool Steel, Shot Peened
  • Our Phosphate/Chrome BCGs ship with an upgraded Sprinco Extractor Kit

Additional information

  • Weight 0.7875 lbs
  • Dimensions 8 × 1.25 × 1.25 in




Technical Information

Caliber 5.56 NATO / .223 Remington , .300 AAC Blackout
Finish Chrome-lined , Phosphate
Material 8620 Steel , Carpenter 158
Color / Pattern

Catalog Location

California Prop 65 Warning

WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information visit