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.
Sort
Filter
Show In-Stock Only?
Price
Brand
- Lower Receiver Parts - AT3 Tactical (51)
- Lower Receiver Parts - Strike Industries (21)
- Lower Receiver Parts - Armaspec (13)
- Lower Receiver Parts - Battle Arms Development (11)
- Lower Receiver Parts - Radian Weapons (9)
- Lower Receiver Parts - Timber Creek (8)
- Lower Receiver Parts - CMMG (8)
- Lower Receiver Parts - Odin Works (7)
- Lower Receiver Parts - Phase 5 (6)
- Lower Receiver Parts - Magpul (6)
- Lower Receiver Parts - Aero Precision (6)
- Lower Receiver Parts - Luth-AR (4)
- Lower Receiver Parts - LBE Unlimited (4)
- Lower Parts - Fortis (4)
- Lower Receiver Parts - Sons of Liberty Gun Works (3)
- Lower Receiver Parts - KE Arms (3)
- Lower Receiver Parts - JP Enterprises (3)
- Lower Receiver Parts - Ergo (3)
- Lower Receiver Parts - Tyrant CNC (2)
- Lower Receiver Parts - Troy (2)
- Lower Receiver Parts - Mission First Tactical (2)
- Lower Receiver Parts - Kaw Valley Precision (2)
- Lower Receiver Parts - KAC (2)
- Lower Receiver Parts - Badger Ordnance (2)
- Lower Receiver Parts - B5 Systems (2)
- Lower Receiver Parts - Arms Unlimited (2)
- Lower Receiver Parts - Anderson (2)
- Lower Receiver Parts - Yankee Hill Machine (1)
- Lower Receiver Parts - Wilson Combat (1)
- Lower Receiver Parts - Timney Triggers (1)
- Lower Receiver Parts - Rise Armament (1)
- Lower Receiver Parts - KNS Precision (1)
- Lower Receiver Parts - Guntology (1)
- Lower Receiver Parts - Geissele (1)
- Lower Receiver Parts - Elftmann Tactical (1)
- Lower Receiver Parts - CMC Triggers (1)
- Lower Receiver Parts - Bravo Company (1)
Caliber
Color
- Lower Receiver Parts - Black (114)
- Lower Receiver Parts - Flat Dark Earth (59)
- Lower Receiver Parts - Red (45)
- Lower Receiver Parts - Blue (40)
- Lower Receiver Parts - OD Green (39)
- Lower Receiver Parts - Gray (31)
- Lower Receiver Parts - Tungsten (22)
- Lower Receiver Parts - Burnt Bronze (21)
- Lower Receiver Parts - Pink (17)
- Lower Receiver Parts - Titanium (16)
- Lower Receiver Parts - Purple (10)
- Lower Reciever Parts - Silver (10)
- Lower Receiver Parts - Gold (5)
- Lower Receiver Parts - Stainless (4)
- Lower Receiver Parts - Tan (3)
- Lower Receiver Parts - Brown (1)
- Lower Receiver Parts - NP3 (1)
List
Grid
-
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 -
Armaspec SFT45/90 Ambi AR 15 Safety Selector – ARM113
Armaspec 45 and 90 Degree Ambi Safety The Armaspec SFT45/90 allows you to modify your AR-15 safety exactly how you like it. This AR-15 safety upgrade features a double-sided steel...6 Options -
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™NEWUpgrade Sale!
AT3 Tactical AR-15 Ultimate Cerakote Color Upgrade Kit
Cerakote Color Accent Parts Kit with Buffer Tube and Ambi Safety The Ultimate Cerakote Color Upgrade Kit completely overhauls your lower receiver, from takedown pins to buffer tube. Enhance function...8 Options8 Options8 Options$99.99$89.99 -
AT3™NEWUpgrade Sale!
AT3 Tactical AR-15 Cerakote Color Upgrade Kit
Cerakote Color Accent Parts Kit Cerakote color parts for your AR-15 can enhance your build and help you stand out, or blend in. This Cerakote parts kit includes replacements for...8 Options8 Options8 Options$27.99$25.19 -
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™RECOMMENDEDUpgrade Sale!
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 -
Magpul MOE Enhanced AR-15 Trigger Guard
Transform Flat Mil-Spec Dimensions into Tactile Ergonomic Perfection The MOE Enhanced trigger guard overhaul ushers forgiving glove integration and positive control to the overlooked lower receiver component. Ditch the awkward...3 Options3 Options3 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™RECOMMENDED
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 Options -
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 -
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 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 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 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 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 -
AT3™
AT3™ Mil-Spec AR-15 Magazine Catch – 10 Colors Available
Mil-Spec AR-15 Magazine Catch This magazine catch meets and exceeds mil-spec demands. Steel construction with proper threading and dimensions, plus a durable Melonite finish to lasting wear protection. If you...10 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 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 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... -
Guntology PDQ Ambidextrous AR-15 Bolt Release
Ambidextrous AR-15 Bolt Catch - Convert Any Mil-Spec Lower The PDQ (Pretty Damn Quick) Ambidextrous bolt release upgrades your AR-15 for ease of use, whether you're right or left handed.... -
AT3™
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...
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