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

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

The Sons of Liberty Gun Works (SOLGW) Hard Chrome Bolt Carrier Group is built to be the heart of your AR platform—precision-engineered for reliability, durability, and performance under the harshest conditions. If the gas port is the lungs, the bolt carrier group is the heart, driving every cycle of operation: locking, unlocking, extracting, and ejecting.

Crafted from Carpenter 158 chrome-nickel alloy and subjected to rigorous mil-spec heat treatment, shot peening, high-pressure testing, and magnetic particle inspection, this BCG is designed to withstand extreme use. Every component, from the precision-machined extractor to the hard chrome bore carrier, is engineered for flawless function and long-term reliability.

With the Sons of Liberty Battle Flag logo laser-engraved, this BCG represents uncompromising craftsmanship and a commitment to excellence. Whether you’re building a duty rifle, upgrading your AR, or demanding the highest standards for your firearm, the SOLGW Hard Chrome BCG delivers unmatched confidence and performance.

Full-Auto Profile Carrier
Machined from AISI 8620 aircraft-quality alloy, hard chrome bore, precision-ground gas key interface.

Carpenter 158
Precision-machined Bolt, heat-treated, shot-peened, HP tested, and MPI inspected for maximum durability.

4340 Tool Steel Alloy
Extractor & Cam Pin Made from 4340 tool steel alloy, stronger than 4140, heat-treated and shot-peened for reliability.

S7 Tool Steel
Extractor Retaining Pin and Ejector precision-ground S7 tool steel, heat-treated and shot-peened to mil-spec.

4130 Chromoly Steel
Gas Key, heat-treated, hard chrome internal, Permatex sealed, Grade 8 screws torqued and staked.

8640 Steel Alloy
Firing Pin, heat-treated, hard chrome plated for smooth function.

1038 Carbon Steel
Precision-machined Firing Pin Retaining Pin, heat-treated per mil-spec.

Specifications

• Bolt Material: Carpenter Technology No. 158 chrome-nickel alloy
• Bolt Treatment: Heat-treated, shot-peened, vibratory tumbled
• Testing: HP proof tested, full-auto test fired, MPI inspected
• Extractor Material: 4340 tool steel alloy
• Extractor Retaining Pin: S7 tool steel, heat-treated
• Extractor Spring: Chrome silicon wire, cryogenic processed, molybdenum-disulfide infused
• Ejector Material: S7 tool steel, heat-treated
• Gas Rings: Stainless steel, mil-spec x3
• Carrier Material: AISI 8620 aircraft-quality alloy, full-auto profile, hard chrome bore
• Gas Key Material: 4130 Chromoly steel, Permatex sealed, Grade 8 screws staked
• Cam Pin Material: 4340 Chromoly steel, solid film lubricant applied
• Firing Pin Material: 8640 steel alloy, hard chrome plated
• Firing Pin Retaining Pin: 1038 carbon steel, heat-treated
• Finish: Hard chrome bore with deep laser engraving