This Lower Parts Kit from ALG Defense bundles the small internal parts needed to complete a stripped AR-15 lower receiver — hammer, disconnector, springs, detents, pins, and the buffer retainer and takedown pin hardware — built around ALG’s ACT (Advanced Combat Trigger), an upgraded single-stage trigger designed for a lighter, crisper pull than ALG’s base QMS trigger (ALG Defense part no. 16-003).

Key Specifications

• Includes the hammer, disconnector, and their springs to complete the fire control group.
• Also includes the detents, pins, buffer retainer, and takedown pin hardware needed to finish the lower.
• Built around ALG’s ACT (Advanced Combat Trigger), an upgraded single-stage trigger.
• Does not include a pistol grip.
• Sold as a small-parts kit, not a complete firearm — it’s classified as a firearm accessory, so no FFL transfer is required to buy it.

Frequently Asked Questions

What trigger does this kit include? ALG’s ACT (Advanced Combat Trigger), an upgraded single-stage trigger designed for a lighter, crisper pull than ALG’s base QMS trigger.

Does this kit include a pistol grip? No, this version does not include a grip; ALG also sells a with-grip version of this kit.

Buy the AR-15 Lower Parts Kit with ACT Trigger

Finish your stripped AR-15 lower build with this ALG Defense parts kit and upgraded ACT trigger. It ships fast from our Lubbock, Texas gun shop, and our AR lower parts kits selection has more lower parts kit options.