Lower Parts Kit for AR-15
From complete kits to individual pieces, AT3 has the lower parts you need to build your ultimate AR-15.
We provide high-quality lower receiver parts kit, safety selector, and mag release. READ MORE
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- Lower Receiver Parts - AT3 Tactical (49)
- Lower Receiver Parts - Strike Industries (13)
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AT3™St. Patty's Sale
AT3™ FU-BAG™ AR-15 Lost Parts Kit – Springs, Detents, Replacement Components
Made an "Oops" with your New Build? You Detent-Launchin', Spring-Losin' Fool, you. We've all been there. Whether it's rolling the dice on that bargain bin LPK in your local...2 Options -
St. Patty's Sale
CMMG .308 Lower Receiver Parts Kit
All the Parts You Need to Get Started on Your Next Mk3 Build Combine this kit with a buttstock kit to complete your lower group. Compatible with CMMG Mk3 Lowers... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs – Set of 2
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs - Set of Two All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and... -
AT3™St. Patty's Sale
AT3™ MOTHERFU-BAG™ – The BIG AR-15 Lost Parts Kit – Springs, Detents, Wear Parts,...
Launch a detent? Snap a spring? Don't get mad, just fix it with this AR-15 Lost Parts Kit! Alright, so y'all seem to like the FU-BAG. Like a lot. Which... -
AT3™St. Patty's Sale
AT3™ Castle Nut for AR-15 Buffer Tubes – 10 Colors Available
Secure Your AR15 Buffer Assembly with a Steel Castle Nut This steel castle nut is an essential piece of an AR15 buffer tube/stock assembly. With standard cuts for use with...10 Options -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Buffer Retainer Spring
Mil-Spec AR-15 Buffer Retainer Spring All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR buffer assembly and... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Selector Detent
Mil-Spec AR-15 Selector Detent All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR safety assembly and are... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Bolt Catch Spring
Mil-Spec AR-15 Bolt Catch Spring All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR lower receiver and... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Selector Detent Spring
Mil-Spec AR-15 Selector Detent Spring All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR mag catch assembly... -
AT3™RECOMMENDEDSt. Patty's Sale
AT3™ AR-15 Enhanced Billet Trigger Guard Assembly
AT3 Billet Trigger Guard - Perfect for Winter and Gloves This billet aluminum trigger guard works with all mil-spec lower receivers, and makes additional room for manipulating the trigger. The...$9.99Only$8.49 -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Bolt Catch Plunger
Mil-Spec AR-15 Bolt Catch Plunger Looking for a high-quality bolt Catch Plunger for your AR-15? Look no further than AT3 Tactical. Our Bolt Catch Plunger is designed to meet or... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Buffer Retainer
AT3 Tactical Mil-Spec AR-15 Buffer Retainer If you're looking for a reliable buffer retainer for your AR-15, look no further than the Mil-Spec AR-15 Buffer Retainer from AT3 Tactical. Made... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Magazine Catch Spring
Mil-Spec AR-15 Magazine Catch Spring All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR mag catch assembly... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Pistol Grip Screw
AT3 Mil-Spec AR-15 Pistol Grip Screw Looking for a reliable replacement for your lost or damaged AR-15 Pistol Grip Screw? Look no further than AT3 Tactical. Our Mil-Spec AR-15 Pistol... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Pistol Grip Lock Washer
Mil-Spec AR-15 Pistol Grip Lock Washer If you're looking for a Pistol Grip Lock Washer that meets or exceeds Mil-Spec, look no further than AT3 Tactical. Our lock washers are... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Bolt Catch Pin
Mil-Spec AR-15 Bolt Catch PIN Looking for a high-quality Bolt Catch Pin for your AR-15? Look no further than AT3 Tactical. Our bolt catch pin is designed to meet or... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Disconnector Spring
Mil-Spec AR-15 Disconnector Spring Looking for a durable and reliable Disconnector Spring for your AR-15 trigger? Look no further than AT3 Tactical. Our Disconnector Spring is designed to meet or... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Trigger Guard Roll Pin
Mil-Spec AR-15 Trigger Guard Roll Pin All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR trigger guard... -
St. Patty's Sale
Magpul Enhanced AR-15 Magazine Release – MAG568
Enhanced Mag Release For A Smooth & Fumble-free Magazine Changes The Magpul Enhanced Magazine Release - MAG568 is designed with a larger contact surface making it easily accessible to all... -
St. Patty's Sale
Magpul Bad Lever | Battery Assist Device for AR-15 – MAG980
Speed Up The Bolt Catch with this B.A.D. Lever from Magpul The B.A.D. Lever (Battery Assist Device) is designed to considerably improve the speed and efficiency of the AR15/M16 bolt... -
St. Patty's Sale
Ergo Trim to Fit AR15 Receiver Wedge – 3 Pack
Ergo Trim to Fit AR15 Receiver Wedge - 3 Pack The Ergo Grip AR15 Receiver Wedge is an essential tool for any AR-15 owner who wants to reduce the amount... -
AT3™St. Patty's Sale
AT3™ Mil-Spec AR-15 Hammer/Trigger Pins – 2 Pcs
Mil-Spec AR-15 Hammer/Trigger Pins (2 Pieces) All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR trigger assembly... -
St. Patty's Sale
Strike Industries Extended Bolt Catch for AR15
A "Go Fast" Addition To Your Next Build The Strike Industries Extended Bolt Catch is a heavy-duty and reliable upgrade that makes your AR-15 quicker and easier to operate. It... -
AT3™St. Patty's Sale
AT3™ AR 15 Enhanced Lower Parts Kit with Nickel Teflon Trigger – No Grip...
Tired of swapping out parts? Build the lower you actually want. This premium lower parts kit features our AT3 Enhanced Nickel Teflon Trigger, giving you the quality trigger your rifle...
Other Lower Receiver Components for AR 15:
AR 15 Buffer Tube Parts (Receiver Extension)
AR-15 Triggers
Buttstocks
Lower Parts Kit for AR-15
Magazines & Parts
Pistol Grips
AR-15 Trigger Guards