Gun Nuts® Sporter Lower Parts Kit

Notched-Hammer Sporter Lower Parts Kit for Older and Surplus AR-15 Uppers

Many vintage Colt, Bushmaster and surplus AR-15 uppers run unshrounded bolt carrier groups, and a standard hammer can strike the carrier in those rifles. Gun Nuts cuts a notch into the hammer in this Sporter kit to clear them, so you can put a fresh lower under an older upper, or restore a classic build, without hunting down an old-style hammer.

Everything else you need to finish a stripped lower is here too: precision-machined fire control parts that cycle reliably, an ambidextrous safety selector for right- or left-handed shooters, plus the pistol grip, trigger guard, pins and springs.

What's in the Kit

Fire Control Group

• Notched hammer
• Trigger
• Disconnect
• Hammer spring
• Trigger spring
• Disconnect spring
• Hammer pin
• Trigger pin

Safety Selector

• Ambidextrous safety selector
• Selector detent
• Selector detent spring

Pins, Detents and Springs

• Pivot pin, detent and spring
• Takedown pin, detent and spring

Bolt Catch and Buffer Retainer

• Bolt catch
• Bolt catch plunger
• Bolt catch spring
• Bolt catch roll pin
• Buffer retainer
• Buffer retainer spring

Magazine Catch

• Magazine catch
• Magazine catch spring
• Magazine release button

Grip and Trigger Guard

• Pistol grip
• Pistol grip screw
• Pistol grip lock washer
• Trigger guard
• Trigger guard roll pin

Installation Instructions

Follow our step-by-step instructions to install your Sporter Lower Parts Kit.