M&P AR-15 Customizable Lower Parts Kit

The M&P AR-15 Customizable Lower Parts Kit is engineered for builders who want dependable reliability without giving up the freedom to tailor their rifle to their own performance needs. Whether you're assembling a new lower from the ground up or refreshing an existing setup, this kit delivers the essential small components required for a proper AR-15 build while intentionally leaving room for your preferred aftermarket trigger, grip, and other upgraded parts. It’s a smart solution for shooters who already know what enhanced components they want to run and don’t need a complete off-the-shelf kit weighing them down with unused pieces.

Every part in this set is built to the same standards trusted across M&P’s firearm lineup, ensuring proper fit and long-term durability through hard use. Each detent, pin, spring, and control surface has been machined or formed for dependable mechanical function, giving you confidence during assembly and performance. With this kit, you’re not just checking boxes—you’re laying a solid foundation for a custom AR-15 that reflects your style of shooting, whether that means defensive readiness, competitive performance, or general field reliability.

The layout of this kit also supports smooth installation. Components are clearly defined, sized correctly, and ready to drop into any Mil-Spec style lower receiver. By supplying the core controls—magazine catch, selector, bolt catch, and all necessary detents and springs—the kit covers every minor part that often slows down a build or requires hunting for individual components. The result is a cleaner, more efficient assembly process from start to finish.

This is a builder’s kit that respects your choices, supports aftermarket flexibility, and ensures high-quality parts in the areas that matter most. With M&P’s reputation backing it, you can trust that every piece is designed to function, endure, and perform.

Kit includes:
• Bolt Catch
• Bolt Catch Plunger
• Bolt Catch Roll Pin
• Bolt Catch Spring
• Buffer Retainer
• Buffer Retainer Spring
• Hammer Pin
• Magazine Catch
• Magazine Catch Button
• Magazine Catch Spring
• Pivot Pin
• Pivot Pin Detent
• Pivot Pin Detent Spring
• Selector
• Selector Detent
• Selector Detent Spring
• Takedown Pin
• Takedown Pin Detent
• Takedown Pin Detent Spring
• Trigger Pin

Order yours today from Smoky Mountain Knife Works!