Rosco Manufacturing 5.56 / 300 BLK Bolt Carrier Group


Order by 2PM CST for Same Day Shipping*
Shipping As Low As $1.99
100% Live Inventory, No Back Orders

(1 customer review)

3 in stock

Purchase this product now and earn 160 Points!

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


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.

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.

The Rosco Phosphate Bolt Carrier Groups are designed to meet the modern-day carbine shooters requirements. 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 BCG’s 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 upgraded extractor) which is designed to lock up perfectly with our extensions for extreme accuracy. These BCG’s 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 6 oz
Dimensions 2 × 2 × 6 in

1 review for Rosco Manufacturing 5.56 / 300 BLK Bolt Carrier Group

  1. erveyace (verified owner)

    Great bcg . Works perfectly I put over 200 rounds of different grains and brands through it so far and with no problems at all.

Only logged in customers who have purchased this product may leave a review.