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Sons of Liberty Gun Works Bolt Carrier Group HPT/MPI

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.)

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)


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

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
Sons of Liberty Battle Flag logo deep laser engraved
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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