BYD: BCM MK2 300 BLK Upper Receiver Group
Overview
These are not permanent listings and stock is limited — once they’re gone, they’re gone!
It’s no secret that we’re particularly fond of BCM’s MK2 lineup. These MK2 300 Blackout uppers are great suppressor hosts as they feature a continuous-taper profile barrel that keeps the weight back towards the receiver and makes the front light and maneuverable. Pair this with the enhanced MK2 upper receiver, which gives you a relocated forward assist and unmatched rigidity, and you have an accurate and consistent foundation that will be ready to perform for years to come. Lastly, an often skipped-over feature is BCM’s thermal fit tolerances on both the handguard and barrel extension. This provides superior fit and finish and increases service life and overall consistency.
What's Included
- 1x BCM Upper Receiver with BCG
- 1x M-LOK Picatinny section
- 1x BCM M-LOK QD mount
Specs
Warranty: Covered by BCM’s manufacturer warranty. Warranty service is provided by BCM.
Upper Features
- Manufactured by Bravo Company MFG, Inc. (BCM)
- Fully assembled, headspaced, and test-fired
- Features BCM’s proprietary MK2 upper receiver for enhanced rigidity
- Relocated forward assist for easier charging handle access
- M4 feed ramp barrel extension and upper receiver for reliable feeding
- T-marked upper receiver for easy configuration of tactical accessories
- Mil-Spec barrel steel (Certified Mil-B-11595E) for strength and durability
- Chrome bore and chamber for enhanced chambering, extraction, and reliability
- Manganese phosphate barrel finish for corrosion resistance
- HPT / MP Inspected barrels for quality assurance and flaw detection
Bolt Carrier Features
- BCM (MPI) complete bolt carrier group for AR-15, M16, or M4
- Parkerized exterior with chrome-lined inside carrier
- Machined to USGI specifications, Full Auto Profile
- M16/M4 carrier with Mil-Spec chrome-lined gas key
- Gas key heat-treated and chrome-lined, securely fastened with grade 8 fasteners
- Bolt assembly machined from Mil-Spec Carpenter No. 158 steel, shot peened
- Includes tool steel extractor and ejector
- Includes BCM extractor spring
- HPT (High-Pressure Tested) and MPI (Magnetic Particle Inspected)
- BCM test fires for function before shipping
Upper Specifications
| Caliber | 300 Blackout |
| Barrel Material | 11595E Spec Steel |
| Barrel Finish | Manganese Phosphate (Mil-Spec A-A-59267) |
| Bore & Chamber | Chrome Lined |
| Twist Rate: | 1:7 |
| Gas System | Pistol |
| Muzzle Device | BCM® Comp Mod 1 (762/300BLK) |
| Muzzle Threads | 5/8×24 |
Made in the USA.
Buffer Recommendations
Index:
- Sprinco Hot White: In the middle of a standard carbine spring and the Blue spring, roughly 7-8% stiffer than standard.
- Sprinco Blue: 15% stiffer than standard carbine springs.
- Sprinco Green: Rifle length spring for A5/MK2 buffer systems.
| MK2 9″, MCMR-8, Standard Barrel – Continuous Taper Profile, Pistol Gas | |
| Unsuppressed Supersonic | Carbine: H1 or H2 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: -A5H2/T2 – Rifle or Sprinco Green Spring Law Folder, Carbine: H1 or H2 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H1/T1 or A5H2/T2 – Rifle or Sprinco Green Spring |
| Suppressed Supersonic | Carbine: H2 or H3 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: – A5H3/T3 – Rifle or Sprinco Green Spring Law Folder, Carbine: H1 or H2 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H2/T2 or A5H3/T3 – Rifle or Sprinco Green Spring |
| Suppressed Subsonic | Carbine: Carbine (3.0oz) or H1 – Standard Spring Vltor A5/BCM MK2: A5H1/T1 – Rifle or Sprinco Green Spring Law Folder, Carbine: Carbine (3.0oz) – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H0/T0 or A5H1/T1 – Rifle or Sprinco Green Spring |
| 50/50 Subsonic / Supersonic Suppressed | Carbine: H1 – Standard or Sprinco Hot White Spring Vltor A5/BCM MK2: A5H1/T1 – Rifle or Sprinco Green Spring Law Folder, Carbine: Carbine (3.0oz) or H1 – Standard Spring Law Folder, Vltor A5/BCM MK2: A5H0/T0 or A5H1/T1 – Rifle or Sprinco Green Spring |
** These are approximations. Due to the wide operating range of 300 Blackout it is recommended to do your own testing and confirm functionality. It’s also recommended to shoot the rifle for roughly 200-300 rounds to allow proper break-in and gas system sealing before arriving at a final buffer setup.
Technical Specifications
| Specifications | MK2 9″, MCMR-8, Standard Barrel, Pistol Gas | MK2 9″, MCMR-8, Standard Barrel, Pistol Gas |
| Weight | 3 lb 1.9 oz with Radian Raptor | 3 lb 4.5 oz with Radian Raptor |
| Weight, Standard Lower – No Stock | 4 lb 13.4 oz with Radian Raptor | 5lb with Radian Raptor |
| Weight, Standard Lower – Law Folder, No Stock | 5 lb 8.5 oz with Radian Raptor | 5 lb 11.1 oz with Radian Raptor |
| Length, Upper Only | 17.75″ Muzzle Device to End Of Receiver | 17.75″ Muzzle Device to End Of Receiver |
| Length, Standard Lower – No Stock | 25.18″ Muzzle Device to End Of Carbine Extension | 25.18″ Muzzle Device to End Of Carbine Extension |
| Length, Standard Lower – Law Folder, No Stock | 26.38″ Muzzle Device to End Of Carbine Extension | 26.38″ Muzzle Device to End Of Carbine Extension |
| Length, Standard Lower – Law Folder, No Stock (Folded) | 19.69″ Muzzle Device to Furthest point | 19.69″ Muzzle Device to Furthest point |
Shipping Restrictions
- Cannot be shipped outside the US.
- Cannot be shipped to: AA, AE, AK, AP, AS, FM, GU, HI, MH, MP, PR, PW, VI.