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 (10)
- Lower Receiver Parts - Radian Weapons (9)
- Lower Receiver Parts - Armaspec (8)
- Lower Receiver Parts - Battle Arms Development (8)
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- Lower Receiver Parts - Phase 5 (6)
- Lower Receiver Parts - Timber Creek (5)
- Lower Receiver Parts - Magpul (5)
- Lower Receiver Parts - Sons of Liberty Gun Works (4)
- Lower Receiver Parts - LBE Unlimited (4)
- Lower Receiver Parts - KE Arms (3)
- Lower Receiver Parts - JP Enterprises (3)
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- Lower Receiver Parts - Luth-AR (2)
- Lower Receiver Parts - B5 Systems (2)
- Lower Receiver Parts - Anderson (2)
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- Lower Receiver Parts - KAK Industry (1)
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- Lower Receiver Parts - CMC Triggers (1)
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- Lower Receiver Parts - Black (69)
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AT3™
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 -
AT3™
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™
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs – 2 Pcs
Mil-Spec AR-15 Pivot Pin/Takedown Pin Detent Springs (2 Pieces) All AT3 Tactical lower receiver parts meet or exceed Mil-Spec. These parts are guaranteed to fit and function in your AR... -
AT3™
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detents – 2 or 10 Piece
Mil-Spec AR-15 Pivot Pin/Takedown Pin Detents - 2 Piece or 10 Piece All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and...2 Options -
AT3™
AT3 Tactical 2 Stage Trigger Assembly for AR 15 – 4.5 lb Pull Weight
The Best Upgrade To Your AR-15 - Your Key To Faster And More Accurate Shooting! The AT3 2-Stage Trigger drops into your mil-spec lower for a huge upgrade to your... -
AT3™
AT3™ Pro-Builder™ AR-15 Lower Parts Kit – No Grip or Trigger Assembly
Perfect Lower Parts Kit for the Premium Builds This quality lower parts kit excludes the two most commonly upgraded components - the grip and the trigger assembly (fire control group).... -
AT3™
AT3 Tactical AR-15 Takedown and Pivot Pin Assembly
AR-15 Takedown and Pivot Pins with Springs and Detents If you're completing an AR-15 lower, you won't get far without a good set of takedown and pivot pins. These mil-spec...10 Options -
AT3™
AT3 Tactical AR-15 Safety Selector Assembly with Spring and Detent
AR-15 Safety Selector with Spring and Detent AT3's AR-15 Safety Selector Assembly comes with everything you need to install a new safety or replace your existing parts. This mil-spec style...10 Options -
AT3™
AT3 Tactical AR-15 Magazine Catch and Button Assembly
AR-15 Magazine Catch with Button and Spring Whether you're finishing a build or replacing stock parts, your AR-15 is going to need reliable magazine retention. This mil-spec assembly includes the...10 Options -
AT3™
AT3™ Enhanced Nickel Teflon AR-15 Trigger Assembly
A Simple Upgrade That Will Ultimately Improve The Accuracy And Performance Of Your AR The Enhanced Nickel Teflon trigger assembly features smooth, precision-machined engagement surfaces and Nickel Teflon coating that... -
Armaspec Anti-Walk Trigger and Hammer Pins
Perfect for Drop-In Triggers and Preserving Your Lower Armaspec Stainless Steel Anti-Walk pins are standard .154 sized pins for milspec lowers. These pins are designed to keep your hammer/trigger pins... -
AT3™
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 and are perfect... -
AT3™
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 and are perfect... -
AT3™
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 and are perfect for... -
AT3™
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 and are perfect... -
Anderson Manufacturing AR-15 Lower Parts Kit – Stainless Hammer & Trigger
Everything You Need To Complete Your Lower Receiver The Anderson Manufacturing AR-15 Lower Parts Kit is a complete lower components kit that includes everything you need to complete your lower... -
AT3™
AT3™ Mil-Spec AR-15 Bolt Catch Plunger
Mil-Spec AR-15 Bolt Catch Plunger All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR and are perfect... -
AT3™
AT3™ Ambidextrous AR15 Safety Selector – 10 Colors Available
A Quick Upgrade to Any AR-style Rifle The AT3 AR-15 Ambidextrous Safety Selector replaces your existing selector all allows for enhanced safety control for both right- and left-handed shooters. This...10 Options -
AT3™
AT3 Tactical AR-15 Bolt Catch Assembly with Spring, Plunger, and Roll Pin
Mil-Spec AR-15 Bolt Catch with Hardware The AT3 AR-15 Bolt Catch Assembly has everything you need to upgrade or replace an existing bolt catch on your AR-15 lower. You get...10 Options -
AT3™
AT3™ AR15 Mil-Spec Bolt Catch – 10 Colors Available
Mil-Spec AR-15 Bolt Catch The bolt catch is an essential part of what makes the AR15 such a great rifle. AT3's bolt catch is a great addition to your next...10 Options -
New
Battle Arms Development Enhanced Modular AR-15 Magazine Release
Battle Arms Development Extended Magazine Release The Battle Arms Development Enhanced Modular Magazine Release gives you a larger surface than mil-spec for faster mag changes. The EMMR uses a two-piece...4 Options4 Options4 Options -
Magpul Trigger Guard for AR 15 – MAG417
Curved Shape For Better Use Of Gloves in Cold Weather Operations The Magpul Trigger Guard is a drop-in replacement for the AR15/M4 weapons platform manufactured from enhanced polymer that is...4 Options -
AT3™
AT3™ Mil-Spec AR-15 Buffer Retainer
Mil-Spec AR-15 Buffer Retainer All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit and function in your AR and are perfect for... -
AT3™
AT3™ Mil-Spec AR-15 Pivot Pin – 10 Colors Available
Mil-Spec AR-15 Pivot Pin This heavy-duty Mil-Spec Pivot Pin securely locks into and holds the upper and lower receivers in place. It's made of 8620 Alloy steel and has a...10 Options