Davidson Defense Silent Guardian w/SBA3 Brace 7.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-Lok Handguard Pistol Full Build Kit

Davidson Defense Silent Guardian 7.5" .300 BLK Full Build Kit with SBA3 Brace | 4150 CMV Phosphate | Pistol-Gas | 7" M-Lok Freefloat

The Davidson Defense Silent Guardian .300 BLK 7.5" full build kit with SBA3 Brace is a compact AR-15 pistol build kit chambered in .300 BLK for maximum maneuverability and versatile performance. Built around a 7.5-inch H-Bar barrel with 1:8 twist rate, this kit is constructed from durable 4150 Chrome Moly Vanadium steel with phosphate finish for added resilience and corrosion resistance. The pistol-length gas system ensures reliable cycling, while the micro low-profile gas block optimizes performance in the compact configuration. The upper receiver is crafted from 7075-T6 aluminum with anodized finish for strength, equipped with M4 feed ramps for enhanced feeding reliability. The complete upper includes an AR-15 bolt carrier group made in the USA from 9310 alloy steel with nitride finish, Mil-Spec charging handle, and all necessary lower parts. The kit includes an adjustable SB Tactical SBA3 brace for stability and control, paired with a 6-position mil-spec buffer tube. The 7-inch freefloat M-Lok handguard allows for customizable accessory mounting, made from lightweight 6061-T6 aluminum. The Silent Guardian offers versatility and performance for those seeking a robust pistol platform. This kit includes everything except the lower receiver.

Key Features

• 7.5" H-Bar Barrel: 4150 Chrome Moly Vanadium steel with phosphate finish and 1:8 twist rate chambered in .300 BLK
• Pistol-Length Gas System: Reliable cycling with micro low-profile gas block for optimized performance
• AR-15 Bolt Carrier Group: Made in USA from 9310 alloy steel with nitride finish for enhanced durability
• Mil-Spec Charging Handle: Standard Mil-Spec design for reliable operation and broad compatibility
• 7075-T6 Aluminum Upper Receiver: Anodized finish with M4 feed ramps for strength and feeding reliability
• 7" M-Lok Freefloat Handguard: Lightweight 6061-T6 aluminum for customizable accessory mounting
• SB Tactical SBA3 Adjustable Brace: Stability and control with adjustable length-of-pull
• 6-Position Mil-Spec Buffer Tube: Robust construction for reliable operation and brace compatibility
• Complete Lower Parts Kit: Includes all necessary components for lower receiver assembly
• Full Build Kit: Includes everything to complete the build except the lower receiver

Perfect For

• Compact Pistol Enthusiasts seeking robust platform with versatility and performance in .300 BLK
• Suppressor Users where short barrel length is ideal for subsonic .300 BLK performance
• Home Defense and Tactical Applications where stability, control, and reliable cycling are critical
• Shooters wanting customizable accessory mounting with adjustable brace for enhanced control

H-Bar Barrel Construction

The 7.5-inch H-Bar barrel is constructed from durable 4150 Chrome Moly Vanadium steel with phosphate finish, providing added resilience and corrosion resistance for reliable performance. The H-Bar profile provides enhanced rigidity and improved heat dissipation compared to standard profiles, supporting consistent accuracy during extended shooting sessions—particularly beneficial in the compact configuration where heat management is important. The phosphate finish (also called Parkerized) provides excellent corrosion resistance and has been the military standard for decades. The 1:8 twist rate stabilizes the diverse range of .300 BLK projectile weights, from 110-grain supersonic ammunition for maximum velocity to 220-grain subsonic projectiles ideal for suppressed shooting. This twist rate ensures proper stabilization across the wide ammunition spectrum that makes .300 Blackout particularly versatile. The compact 7.5-inch length is particularly well-suited for .300 Blackout's design, delivering superior ballistic performance in short barrel configurations.

Pistol-Length Gas System and Upper Receiver

The pistol-length gas system ensures reliable cycling, while the micro low-profile gas block optimizes performance in the compact configuration with consistent extraction and ejection. The pistol-length gas system is the shortest standard gas system length, positioned closer to the chamber to ensure adequate gas pressure for reliable operation in very short barrel applications. The micro low-profile design provides a streamlined profile that fits cleanly under freefloat handguards. This gas system length is particularly effective with .300 Blackout, which generates appropriate gas pressure for dependable cycling with both supersonic and subsonic ammunition. The 7075-T6 aluminum upper receiver with anodized finish is crafted for strength, offering exceptional strength-to-weight ratio. The M4 feed ramps enhance feeding reliability across diverse .300 BLK ammunition types.

USA-Made Bolt Carrier Group and Charging Handle

The included AR-15 bolt carrier group is made in the USA from 9310 alloy steel with nitride finish, providing enhanced durability through superior material selection and manufacturing. The 9310 alloy steel is selected for its exceptional strength and fatigue resistance, providing excellent wear resistance for reliable long-term performance. The nitride finish enhances surface hardness and corrosion resistance, reducing friction for smoother operation while supporting consistent cycling and extraction performance across thousands of rounds. Paired with a Mil-Spec charging handle, the complete upper ensures reliable operation and broad compatibility with aftermarket upgrades and accessories.

M-Lok Freefloat Handguard and SBA3 Brace System

The 7-inch freefloat M-Lok handguard is made from lightweight 6061-T6 aluminum, allowing for customizable accessory mounting while maintaining reduced weight for improved handling. The freefloat design isolates the barrel from external contact, supporting enhanced accuracy potential by eliminating pressure points that can affect barrel harmonics. The M-Lok attachment system provides versatile mounting points for lights, laser devices, vertical grips, and other accessories at multiple positions, allowing shooters to configure the platform for diverse applications. The 7-inch length provides substantial coverage while maintaining the compact profile critical for maneuverability. The SB Tactical SBA3 adjustable brace provides stability and control with adjustable length-of-pull for enhanced shooter comfort in compact pistol platforms. The adjustable design allows shooters to customize length for improved control and adaptability across different shooting positions, representing proven SB Tactical stabilizing brace technology. Paired with a 6-position mil-spec buffer tube, the brace system ensures robust construction for reliable operation.

Complete Build Package

The kit includes a complete lower parts kit with all necessary components for lower receiver assembly. This full build kit delivers a comprehensive solution offering versatility and performance for those seeking a robust pistol platform in the efficient .300 BLK caliber. The combination of durable H-Bar barrel with phosphate finish, reliable pistol-length gas system, USA-made nitride BCG, customizable M-Lok handguard, and adjustable SBA3 brace creates the Silent Guardian—a complete package engineered for compact maneuverability with proven performance and stability.

Follow safe handling practices and manufacturer instructions for assembly and use. Ensure compliance with all applicable federal, state, and local laws regarding pistol configurations and stabilizing braces. This kit is chambered in .300 BLK. This kit includes all necessary components to complete the build—lower receiver sold separately.