M&P AR-15 Complete Lower Parts Kit from Smith&Wesson

The Kit includes everything you need to build your finished lower receiver. All you need is a stripped lower receiver and stock assembly of your choice.
M&P® AR-15 Rifle Complete Lower Parts Kit Includes: Bolt Catch, Bolt Catch Plunger, Bolt Catch Roll Pin, Bolt Catch Spring, Buffer Retainer, Buffer Retainer Spring, Disconnector, Disconnector Spring, Hammer, Hammer Pin, Hammer Spring, Magazine Catch, Magazine Catch Button, Magazine Catch Spring, Pistol Grip, Pistol Grip Lock Washer, Pistol Grip Screw, Pivot Pin, Pivot Pin Detent, Pivot Pin Detent Spring, Selector, Selector Detent, Selector Detent Spring, Trigger, Trigger Guard, Trigger Guard Roll Pin, Trigger Pin, Trigger Spring