.308 80% Lower – Billet: Precision Machined for Your Custom Build

When building a reliable large-frame AR platform, the foundation begins with the lower receiver. The .308 80% lower – billet represents a critical starting point for the discerning builder who values material integrity and exacting tolerances over convenience. Machined from a solid block of 7075-T6 aluminum, this component is designed to accept DPMS-pattern .308 components, offering a robust platform for both hunting and precision shooting applications. Every contour and pocket is cut to mil-spec dimensions, ensuring compatibility with a wide range of aftermarket upper receivers, trigger groups, and buffer systems.

Overview

The .308 80% lower – billet is an unfinished lower receiver that requires the end user to complete the fire control pocket, trigger pin holes, and safety selector detent channel. Sourced from a U.S.-based manufacturer specializing in precision CNC work, this billet lower starts as a raw extrusion and is machined to 80% completion. The remaining 20% of the material removal is left to the builder, allowing for a custom, legal, and personally fabricated firearm component. This specific variant is designed for the AR-308 platform, not AR-10 or LR-308, and uses the standard DPMS high-profile tang for upper receiver compatibility.

Features & Specs

This .308 80% lower – billet is constructed from 7075-T6 aluminum, then hard coat anodized to MIL-A-8625F Type III Class 2 specifications. The billet construction eliminates casting imperfections and provides superior grain structure compared to forged receivers. All critical dimensions—including the trigger pocket width, hammer pin location, and buffer tube thread pitch—are held to +/- 0.001-inch tolerances. The receiver features an integral trigger guard, flared magazine well for faster reloads, and a rear takedown pin detent recess that is pre-drilled for convenience.

• Material: 7075-T6 aluminum billet, hard coat anodized black
• Platform: DPMS-pattern .308 (high-profile tang)
• Completion requirement: 80% unfinished; requires drilling of trigger pin holes and fire control pocket finishing
• Includes: integral trigger guard, flared magwell, threaded bolt catch pin

The billet construction allows for sharper external contours and tighter internal radii than forged lowers. The magazine catch pocket is pre-cut for standard DPMS .308 magazines, and the bolt catch recess is broached to accept standard AR-308 bolt catch assemblies. The lower is also compatible with most drop-in trigger units once the fire control pocket is properly finished.

• Finish: Type III Class 2 hard coat anodizing, non-reflective matte black
• Thread pitch: 1-3/16-16 for buffer tube (standard AR-308 pattern)
• Weight: 11.2 ounces (unfinished)
• Compatibility: Accepts DPMS-pattern .308 upper receivers, buffer tubes, and stock systems

The trigger pocket is machined to a depth of 1.250 inches with side walls at 0.750 inches wide. The hammer pin and trigger pin locations are marked with dimples on the exterior for reference during finishing. The safety selector detent spring hole is pre-drilled to 0.125 inches. The bolt catch plunger hole is also pre-drilled, reducing the complexity of the finishing process.

• Pre-drilled features: Rear takedown pin detent, safety selector detent, bolt catch plunger
• User-finish required: Trigger pin holes, hammer pin hole, fire control pocket depth and width
• Bolt catch: Standard AR-308 pattern, uses a plunger and spring (not included)

Who It’s For

This .308 80% lower – billet is intended for the experienced firearm builder who has access to a drill press, end mill, or jig system specifically designed for 80% lowers. It is not recommended for first-time builders or those unfamiliar with the AR-308 platform due to the tighter tolerances and specific jig requirements. This product is ideal for precision rifle builders, long-range shooters, and hunters who want a custom-tuned .308 rifle without the constraints of a fully completed receiver. The billet construction provides a stiffer, more dimensionally stable platform for match-grade barrels and precision triggers.

Shipping & FFL

This .308 80% lower – billet is not a firearm and does not require transfer through a Federal Firearms License (FFL) holder. It may be shipped directly to your residence or business address. However, the purchaser must be at least 21 years of age and legally permitted to possess firearm components under all applicable federal, state, and local laws. It is the sole responsibility of the buyer to verify that the possession and completion of an 80% lower receiver is legal in their jurisdiction. Some states and municipalities have specific restrictions on unfinished receivers. By purchasing this product, you certify that you are not prohibited from possessing firearms or firearm components under the Gun Control Act of 1968 or any applicable state law.