RiflesSpecialist Builder Set, AR-15, 13.1″,BLK
SPECS.
Additional information
| Color |
Stellar Black |
|---|---|
| Material |
Aerospace 7075-T6 Aluminum |
| Handguard Length |
13.1" |
| Platform Compatibility |
AR15 / M16 / M4 |
| Ambi-Bolt Release |
Yes |
A purpose-built builder’s platform for 13.9” pinned-and-welded rifles. Includes the Specialist ambidextrous lower (with ambi bolt release installed), Specialist upper receiver, and 13.1” Specialist handguard. Engineered for performance, durability, and perfect aesthetic alignment.
Original price was: $1,245.00.$871.00Current price is: $871.00.
The Stellar Specialist Builder Set
13.1” is the foundation for building a professional-grade rifle with the aggressive performance profile the Specialist series is known for. Engineered specifically to pair with 13.9” barrels (pin & weld to 16” overall legal length), this builder’s set provides a precision-matched geometry between the upper, lower, and handguard for a seamless, uninterrupted aesthetic and functional interface.
The Specialist Ambidextrous Lower is machined from 7075-T6 aerospace-grade aluminum and ships with the ambi bolt release pre-installed, giving builders a factory-aligned ambidextrous control surface. The upper receiver is match-cut to the lower for tight fitment, improved rigidity, and consistent barrel alignment under heat and recoil cycles.
The 13.1” Specialist Handguard features a lightweight, rigid free-float architecture with mission-driven ergonomics. The extended grip section provides positive traction in dynamic positions, while the length is specifically engineered to clear 13.9” muzzle devices for legal pin/weld configurations.
M-LOK slots at strategic positions allow easy attachment of lights, IR lasers, grips, or bipods without unnecessary bulk.
Whether you’re building a duty rifle, a premium home-defense setup, or a high-performance carbine, the Specialist Builder Set gives you the strongest starting point possible.
AMBI Selector Features
