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 (11)
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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 – 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™
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detents – 2 or 10 Piece Set
AT3™ Mil-Spec AR-15 Pivot Pin/Takedown Pin Detents - 2 or 10 Piece Set All AT3 Tactical lower receiver parts meet or exceed Mil Spec. These parts are guaranteed to fit...2 Options -
AT3™
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™
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™ 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)....10 Options -
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 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 -
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 buffer assembly and... -
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™ 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™
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™
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™
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™ 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 -
AT3™
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™
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. This US made pin is made of 8620 Alloy...10 Options -
AT3™
AT3™ Mil-Spec AR-15 Takedown Pin – 10 Colors Available
Mil-Spec AR-15 Takedown Pin The AT3 AR-15 Takedown pin is perfect for replacing a lost part or starting a new build. It has steel construction with a long-lasting phosphate finish,...10 Options -
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... -
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
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™
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...