Black River Tactical M4A1 Bolt Carrier Group

Black River Tactical M4A1 Bolt Carrier Group

The Black River Tactical Bolt Carrier Group features an M16 profile and is tested to ensure a lifetime of reliability.

Bolt:

• Precision machined from Carpenter Technology No. 158 alloy,
• Heat treated per mil-spec,
• Shot peened per ASTM B851/SAE AMS2430S,
• Vibratory tumbled
• Individual high pressure/proof (HP)
• Full Auto test fired as an assembly
• Individual magnetic particle inspection ASTM E1444/E1444M (MP)
• Markings deep laser engraved (SP=Shot Peened, HP=High Pressure Tested, MP=Magnetic Particle Inspection.)

Extractor:

• Precision machined from 4340 tool steel alloy per SAE AMS6415T/AMS6484D (vs 4140),
• Heat treated
• Shot peen per ASTM B851/SAE AMS2430S.

Extractor Retaining Pin:

• Precision machined and ground S7 Tool Steel
• Heat treated per ASTM A681-08
• Shot peened per mil-spec print
• Manganese phosphate

Extractor Spring:

• Tactical Springs/Sprinco 5 coil, ASTM Grade A401 Chrome Silicon wire stock
• Heat treated
• Stress relieved, Molybdenum-Disulfide infused
• Cryogenic processed (all post winding)
• Mil-spec black insert/synthetic elastomer extractor buffer (nitrile-butadiene, shore hardness 80+/-5 durometer per MIL-PRF-6855)

Ejector:

• S7 Tool Steel
• Heat treated per ASTM A681-08
• Shot peened per Mil-Spec
• Manganese phosphate

Ejector Spring:

• Heat treated
• Mil Spec

Gas Rings:

• Standard stainless steel per Mil-Spec X3

Carrier:

• Machined from AISI 8620 aircraft qualty alloy per ASTM A108/A322-13
• Full auto profile
• Heat treated
• Carburized/strain relieved, hard chrome bore
• Precision ground gas key interface
• Manganese phosphate

Gas Key:

•  Machined from 4130 chromoly steel alloy per ASTM A108/A322-13
• Heat treated, hard chrome internal
• Manganese phosphate
• Permatex sealed
• Grade 8 hex screws torqued and staked all per mil-spec

Cam Pin:

• Precision machined 4340 chromoly steel alloy per SAE AMS6415T/AMS6484D
• Heat treated/processed per mil-spec
• Manganese phosphate
• Solid film lubricant applied and cured per mil-spec

Firing Pin:

• Precision machined 8640 steel alloy
• Heat treated/processed per mil-spec
• Hard chrome plate

Firing Pin Retaining Pin:

• Precision machined from 1038 carbon steel
• Heat treated/processed per mil-spec
• Manganese phosphate

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