Daniel Defense Complete AR-15 Lower Receiver Parts Kit Semi-Auto - 05-013-21007
Product Description
Standard commercial-grade lower parts kits sourced from bulk production bins frequently introduce severe quality control bottlenecks to custom rifle projects. Builders routinely battle gritty, unpredictable trigger breaks, out-of-spec detent channels, mushy safety selectors, and soft roll pins that readily mushroom under an armorer’s punch. In a defensive or hard-use firearm, an unreliable small parts group can directly induce catastrophic safety failures, hammer follow, or light primer strikes. The Daniel Defense Semi-Automatic Lower Receiver Parts Kit completely eliminates these engineering shortfalls, delivering a highly curated, premium-tier package of internal controls and springs built to exceed rigorous military specifications for dimension, metallurgy, and performance.
Every single spring, pin, detent, and fire control component within this premium kit is CNC-machined from ultra-durable, select-grade carbon steel forgings and case-hardened alloy matrices. The single-stage semi-automatic hammer is engineered with an integrated internal J-pin to guarantee absolute retention on the hammer pin under punishing vibrational stress, while the matching disconnector and trigger hooks are surface-ground to mirror-smooth finishes that banish heavy, stacking creep. Each steel part receives an advanced anti-corrosive Manganese Phosphate or black oxide conversion treatment that dramatically elevates surface hardness and optimizes oil retention. The package is completed with an ergonomic overmolded pistol grip and an enhanced polymer trigger guard designed to accommodate gloved hands without compromising receiver frame security.
In application, this premium lower parts kit entirely redefines the mechanical feedback of a baseline receiver block. Takedown and pivot pins slide through their channels with smooth, hydraulic-like consistency, while the included safety selector snaps sharply into its indexing detents with zero mushy play. The factory-matched single-stage trigger group produces a crisp, clean duty-weight break followed by a positive mechanical reset that you can easily track through your trigger finger for immediate follow-up shots. Whether finishing a custom stripped lower receiver forging, building out a high-stakes defensive carbine, or executing a comprehensive frame refresh on an active-duty patrol rifle, this Daniel Defense package locks in the structural uniformity required for fail-safe cycling.
*Armorer Bench Notes & Technical Maintenance Guidance: During lower receiver assembly, pay close attention to the orientation of the hammer spring legs; they must rest completely flat on top of the trigger pin to provide proper downward tracking pressure and prevent the pin from walking loose during extended live-fire strings. Always utilize a dedicated 3/32" roll pin punch and a starter block when securing the bolt catch to mitigate the risk of permanently marring or shearing off the receiver's aluminum mounting ears. Before pinning the fire control group into place, apply a light drop of high-viscosity synthetic lubricant or molybdenum disulfide grease directly to the primary trigger sear nose and the disconnector engagement surfaces to smooth out the initial break. While this kit is machined to perfect mil-spec tolerances to interface seamlessly with high-tier lowers, pairing it with low-quality cast or out-of-spec receivers may require minor hand-fitting of the pivot pin detent channels.
Key Features
- Premium Fire Control Group: Outfitted with a complete single-stage semi-automatic trigger, case-hardened hammer, and disconnector setup to deliver a clean, crisp duty-grade break.
- Manganese Phosphate Armoring: Core steel parts receive a heavy mil-spec parkerized coating to minimize mechanical friction, repel surface corrosion, and lock in protective lubricants.
- Enhanced Polymer Ergonomics: Includes an upgraded tactical pistol grip and a wide-body trigger guard configured for enhanced weapon control and seamless use with cold-weather gloves.
- J-Pin Hammer Design: Features an integrated hammer retaining pin that mechanically locks onto the receiver pin, preventing walking under sustained cyclic fire.
- Comprehensive All-In-One Pack: Packages every single internal pin, spring, plunger, and screw needed to finish a stripped lower receiver into a organized, factory-sorted group.
Product Specifications
- Brand: Daniel Defense
- Model Line: Semi-Auto Lower Receiver Parts Kit (LPK)
- MPN/SKU: 05-013-21007
- UPC: 815604010160
- Platform Specific: AR-15 / M16 / M4 Receiver Patterns
- Caliber Fitment: .223 Remington / 5.56x45mm NATO / .300 AAC Blackout
- Trigger Type: Single-Stage Mil-Spec GI Trigger Group
- Grip Style: Daniel Defense Custom Polymer Grip (Black)
- Trigger Guard Type: Enhanced Polymer Trigger Guard Assembly
- Material Base: Hardened Forged Carbon Steel / Structural Polymer / High-Tensile Music Wire Springs
- Finish Configuration: MIL-SPEC Manganese Phosphate / Matte Black Oxide
- Country of Manufacture: United States
