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Questions & Answers
Will this BCG work with the 6 mm ARC cartridge?

yes, the 6.5. grendel type II bolt is what you need for your 6ARC, you can get the whole BCG or you can simply swap the bolt into your 556/300BLK carrier. Just make sure you keep track of which one is in your rig as they will not work for 556 or 300BO and vise versa. would be smart to mark your 6ARC bolt accordingly.

by Colemania, Verified Owner, February 20, 2026
Customer Reviews
Most Recent Reviews
AR15 BCG replacement. by Adrian Plascencia, Verified Owner, April 2, 2026
Bought this as a back up for my current BCG, works good when I broke it in.
Most Recent Reviews
Solid Quality by Charlie, Verified Owner, January 15, 2026
This is a solid bolt for a solid price. After a few dozen rounds, everything cleans up nicely and still feels nice and tight.
Most Recent Reviews
Really a great BCG by Boonegump, Verified Owner, June 3, 2025
It’s a great BCG I haven’t put a crazy amount of rounds through it yet but it’s got a tight snug fit to my Ballistic Advantage barrel. No slop or play!
Read All 3 Reviews

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Product Info for Cryptic 6.5 Grendel - Type ll Bolt Carrier Group (BCG)

Coated bolt carrier group (full auto version) for AR15, M16, or M4 machined from Mil-Spec 8620 aircraft quality steel with shrouded firing pin and Mil-Spec chrome lined interior. BCG includes the proper chrome lined and heat treated gas key. Gas key is secured to carrier with Grade 8 fasteners and properly staked per Mil-Specs. This ensures a strong staking and proper gas system functioning. The bolt assembly is CNC machined from Mil-Spec Carpenter No. 158 steel and shot peened for increased strength per Mil-Spec; includes tool steel extractor with spring and viton O-ring; firing pin chromed finished with firing pin retaining pin and cam pin.image

HPT (High Pressure Batch Tested) and MPI (Magnetic Particle Inspected).

Specifications for Cryptic 6.5 Grendel - Type ll Bolt Carrier Group (BCG):

Manufacturer: Cryptic
Fabric/Material: 4140 heat treated steel
Caliber: 6.5mm Grendel II
Gun Make: AR Platform
Gun Model: M16, M4, AR-15
Hand: Right
Weight: 11.55 oz
Condition: New

Features of Cryptic 6.5 Grendel - Type ll Bolt Carrier Group (BCG)

  • Mil-Spec BCG Machined from 8620 Aircraft Quality Steel and heat treated to 60-61 RC
  • Mil- Spec Gas Key
  • Key Staked with Grade 8 Screws, per Mil-Spec
  • Mil-Spec Carpenter 158 Bolt w/ Spring and Ejector
  • Tool Steel Extractor w/ Spring and viton O-ring
  • Mil-Spec Firing Pin w/ Chrome Finish
  • Mil-Spec Cam Pin
  • Full Auto Carrier (Backward compatible with all semi-auto rifles)
  • BCG Weight 11.55 oz.

Package Contents:

  • Cryptic 6.5 Grendel - Type ll Bolt Carrier Group

Cryptic 6.5 Grendel - Type ll Bolt Carrier Group (BCG) Orderable Models

List of Orderable Models

  • Cryptic 6.5 Grendel - Type ll Bolt Carrier Group BCG, Black Nitride, CC-1206 , MPN: CC-1206 , Code: 4ZT-BCG-CR25-CC-1206
  • Cryptic 6.5 Grendel - Type ll Bolt Carrier Group BCG, Manganese Phosphate, CC-1204 , MPN: CC-1204 , Code: 4ZT-BCG-CR25-CC-1204
  • Cryptic 6.5 Grendel - Type ll Bolt Carrier Group BCG, Nickel Boron, CC-1205 , MPN: CC-1205 , Code: 4ZT-BCG-CR25-CC-1205

Cryptic 6.5 Grendel - Type ll Bolt Carrier Group (BCG) Unavailable & Discontinued Models

List of Unorderable Models

  • USED, Cryptic 6.5 Grendel - Type ll Bolt Carrier Group BCG, Black Nitride, CC-1206 , MPN: CC-1206-EDEMO , Code: 4ZT-BCG-CR25-CC-1206-EDEMO-RE-C
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