CMC Triggers AR-15 Mil-Spec 6-Position Buffer Tube Kit Black - CMC-AR15-BT-MIL-BLK

CMC Triggers AR 15 Mil Spec 6 Position Buffer Tube Assembly Kit 7075 T6 Aluminum Black CMC AR15 BT MIL BLK UPC 810169562406

Product Description

The CMC Triggers® AR-15 Mil-Spec 6-Position Buffer Tube Assembly Kit (SKU: CMC-AR15-BT-MIL-BLK / UPC: 810169562406) provides a complete, duty-ready receiver extension foundation engineered for new rifle builds and critical service replacements. Manufactured to exacting Mil-Spec tolerances, this assembly delivers reliable cycling, structural rigidity, and seamless compatibility with all standard Mil-Spec collapsible carbine stocks on the market today.

Rather than using budget 6061 extrusions, CMC Triggers precision-machines this 6-position buffer tube from premium impact-extruded 7075-T6 aluminum, providing superior tensile strength and fatigue resistance under hard-use recoil impulses. The tube is finished with a MIL-A-8625 Type III Class 2 Hardcoat Anodize to resist surface wear, environmental oxidation, and chemical corrosion. Accompanying the tube are a high-carbon steel castle nut and a Quick Detach (QD) sling mount end plate, both heat-treated for structural toughness and treated with a deep black QPQ nitride finish.

The assembly kit comes completely outfitted with a standard 3.0 oz carbine recoil buffer and a high-tensile steel carbine action spring. These matched internal components deliver balanced bolt carrier deceleration, smooth feeding cycles, and positive lockup across direct-impingement systems. With six precision-machined adjustment notches along the lower guide track, shooters gain customizable length-of-pull settings to accommodate body armor, heavy cold-weather layers, or competition shooting stances.

*Armorer Bench Notes & Real-World Staging Guidance:*

Fitment Matrix: Fits standard AR-15 / M4 / M16 Mil-Spec lower receivers. CRITICAL: Compatible ONLY with Mil-Spec dimension buttstocks (1.148" outer diameter); will not accept Commercial-Spec stocks (1.168" outer diameter). For AR-10/LR-308 builds, the tube will thread correctly but the user MUST install a short 2.5" .308 carbine buffer and .308 action spring; utilizing the included 3.25" AR-15 buffer in a .308 rifle will prevent full bolt carrier rearward stroke and lockback. Torque castle nut to 38-42 ft-lbs and stake the end plate into the castle nut notches in two places using an automatic center punch.

1. Ensure the host firearm is completely clear, magazine removed, and chamber visually and physically verified empty.
2. Thread the castle nut onto the buffer tube with the castle notches facing the rear, slide the QD end plate onto the tube with the alignment tab facing forward toward the receiver, and apply aerosol molybdenum disulfide grease or high-temperature anti-seize to the receiver extension threads.
3. Screw the buffer tube into the lower receiver until the front lip captures the buffer retainer pin and spring, ensuring the tube does not bind the retainer pin downward.
4. Seat the QD end plate firmly into the receiver rear indexing recess, thread the castle nut forward against the plate by hand, and torque to 38-42 ft-lbs using a dedicated armorer's castle nut wrench before staking the end plate detents.
5. Insert the high-tensile carbine action spring and 3.0 oz buffer into the tube until captured by the retainer pin, assemble the upper receiver, and execute a complete dry-fire function check verifying bolt lockback on an empty magazine.

Key Features

• 7075-T6 Billet Aluminum Extension: Machined from heavy-duty impact-extruded 7075-T6 aluminum for ultimate tensile strength and impact resistance over standard 6061 tubes.
• Type III Hardcoat Anodized Finish: Deep matte black MIL-A-8625 Type III Class 2 anodizing provides maximum protection against scratches, surface wear, and field chemicals.
• Complete 5-Piece Assembly Kit: Includes 6-position buffer tube, 3.0 oz carbine recoil buffer, high-tensile spring, castle nut, and QD sling end plate in a single package.
• Integrated QD Sling Swivel End Plate: Machined from high-carbon steel with a 360-degree rotation Quick Detach sling cup, eliminating the need for aftermarket sling adapters.
• Nitride-Treated Hardware: Castle nut and end plate feature QPQ liquid nitriding for superior surface hardness and corrosion prevention.

Product Specifications

• Brand: CMC Triggers®
• Model/Series: AR-15 Mil-Spec 6-Position Buffer Tube Assembly Kit
• MPN / SKU: CMC-AR15-BT-MIL-BLK / CMCAR15BTMILBLK
• UPC: 810169562406
• Tube Diameter: Mil-Spec 1.148" Outer Diameter
• Thread Pitch: 1-3/16"-16 UN
• Tube Material: Impact-Extruded 7075-T6 Aluminum
• Tube Finish: MIL-A-8625 Type III Class 2 Hardcoat Anodize
• Buffer Weight: Standard Carbine 3.0 oz
• Spring Material: High-Tensile Heat-Treated Spring Steel
• Hardware Material: Heat-Treated High-Carbon Steel (QPQ Nitride Finish)
• Platform Compatibility: AR-15 / M4 / M16 Lower Receivers
• Country of Origin: USA