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SOLGW 5.56 Bolt Carrier Group 158 Carpenter SP/HPT/MPI

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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

Additional Details



42 Reviews

  • 5
    Complete Upper

    Published by Mike Connolly on Nov 22nd 2019

    Gentlemen, and ladies?
    Received my complete upper a couple of weeks back, you nailed it. Expect additional orders from buds who have handled it. Keep it up. All the best to you and yours.
    Mike c

  • 1
    Was very excited

    Published by Dominic Johnson on Nov 13th 2019

    I was excited to recieve this in my upper reciever build, but it shipped without it forcing me to purchase a carrier group from a local gun store.

  • 5
    Bolt Carrier Group

    Published by Daniel on Oct 23rd 2019

    I received my BCG in a timely manner and it is by far one of the best quality BCG’s that I own would highly recommend

  • 5

    Published by Chris Goldsmith on Oct 15th 2019

    had lower quality bcg that was starting to cause FTE and FTF - replaced with SOLWG BCG and have had ZERO FTE and FTF since at over 1,000 rounds since the switch and running full time suppressed

  • 5
    Solgw 5.56 BCG

    Published by DJ Smith on Oct 13th 2019

    Of all the different brands I’ve had slide through my uppers, the quality is highest with solgw. Buy one, install it and rack the bolt. You will understand. Straight out of the bag it comes in which is inside an awesome box you can literally feel the difference without even shooting the gun with it. For the money there is not another BCG that will ride in my uppers from now on. Killer work guys

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