Luth-AR LRPK-BLDR Lower Parts Kit AR-15 .223/5.56

The Luth-AR LRPK-BLDR is a lower receiver builder kit intended for the AR-15 platform chambered in .223 Rem/5.56 NATO. Components are American-made and produced to MILSPEC drawings, materials, and heat treat standards. Springs are manufactured from certified 17-4 SST and MILSPEC steel wire to provide traceable, high-quality components for builds. No MIM components are used in this kit.

Key Specifications

• The kit fits the AR-15 platform and is chambered for .223 Rem/5.56 NATO.
• This item is supplied as a Lower Parts Kit for use in lower receiver assembly.
• The make/model is specified as AR-15.
• The finish is listed as Black in the product name.
• Components are American-made and produced to MILSPEC drawings and heat treat standards.
• Internal components are investment cast or machined rather than MIM.
• Springs are made from a combination of 17-4 SST and MILSPEC steel wire with certification.
• The kit is intended for builders who require traceable, MILSPEC-quality lower parts.

This lower parts kit delivers a concise, mil-spec approach for AR-15 builders working in .223 Rem/5.56 NATO. With investment-cast or machined components and certified springs, it provides the traceability and material specifications sought by builders who prioritize durable, standards-based parts for reliable assembly and service life expectations.