Spikes ST5BG01 Bolt Carrier Group 5.56/.223 Full Auto AR-15 M16

The Spikes ST5BG01 Bolt Carrier Group delivers reliable cycling and consistent performance for AR-15 and M16 platform rifles chambered in 5.56x45mm NATO and .223 Remington. This full-auto profile BCG features black phosphate coating for enhanced corrosion resistance and smooth operation across thousands of rounds.

What Makes This Different

The full-auto bolt carrier profile provides increased mass compared to semi-auto carriers, improving extraction and ejection reliability under rapid fire conditions. Black phosphate coating offers superior corrosion protection over standard finishes while maintaining proper headspace tolerances. The carrier meets or exceeds mil-spec dimensions for consistent lockup and timing with standard AR-15 components.

Key Features

• Full-auto bolt carrier profile for enhanced reliability and smoother cycling
• Black phosphate finish provides corrosion resistance and reduces friction
• Mil-spec 8620 steel construction with proper heat treatment
• Compatible with standard AR-15 and M16 upper receivers
• Chambers both 5.56x45mm NATO and .223 Remington cartridges
• Includes complete bolt, carrier, firing pin, cam pin, and retaining pin
• Staked gas key with Grade 8 screws and proper torque specifications

Field testing demonstrates consistent extraction and ejection across temperature ranges from -20°F to 140°F. The phosphate coating maintains lubrication longer than uncoated carriers, extending maintenance intervals during high-volume shooting sessions. Law enforcement agencies report reliable function through suppressed and unsuppressed configurations with various ammunition weights from 55 to 77 grains.

Technical Specs

• Caliber: 5.56x45mm NATO, .223 Remington
• Profile: Full-auto bolt carrier
• Material: 8620 steel carrier, Carpenter 158 steel bolt
• Finish: Black phosphate coating
• Weight: Approximately 11.5 ounces complete
• Compatibility: AR-15, M16, M4 upper receivers
• Gas key: Properly staked with Grade 8 screws
• Country of Origin: United States

Spikes Tactical maintains strict quality control standards with magnetic particle inspection on critical components. The ST5BG01 represents proven engineering focused on function over aesthetics, making it suitable for duty use where reliability cannot be compromised.