AT3™ Pro-Builder™ AR-15 Lower Parts Kit – No Grip or Trigger Assembly

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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).

This is the perfect kit for premium builds that include premium triggers like the AT3 Tactical 2-Stage Trigger.  The kit contains quality, mil-spec parts and provides you with the flexibility to spend money on the parts you want – and none of the extras that will sit in your toolbox.

New Color Options!

We’ve added the option to get a Pro-Builder kit with all the parts you’ll see outside your gun in matching Cerakote! We’ve included a handy guide so you can make sure you’re getting the right color for your build. Naturally, these match with all of AT3’s other Cerakote AR parts.

Cerakote Finishes

  • Flat Dark Earth: H-267 Magpul® Flat Dark Earth
  • OD Green: H-232 Magpul® OD Green
  • Gray: H-188 Magpul® Stealth Grey
  • Pink: H-224 SIG™ Pink
  • Red: H-167 USMC Red
  • Blue: H-171 NRA Blue
  • Burnt Bronze: H-148 Burnt Bronze
  • Tungsten: H-237 Tungsten
  • Titanium: H-170 Titanium

American Made Quality

  • All parts meet or exceed military specifications (Mil Spec)
  • Components are 100% Made in the USA
  • Quality packaging keeps components protected and organized
  • Backed by the AT3 Lifetime Warranty

This Kit Includes:

  • Bolt catch
  • Bolt catch plunger
  • Bolt catch roll pin
  • Bolt catch spring
  • Buffer retainer
  • Buffer retainer spring
  • Magazine catch
  • Magazine catch button
  • Magazine catch spring
  • Pivot pin
  • Pivot pin detent
  • Pivot pin detent spring
  • Selector
  • Selector detent
  • Selector detent spring
  • Takedown pin
  • Takedown pin detent
  • Takedown pin detent spring
  • Pistol grip screw and lock washer
  • Detailed parts diagram included for quick and easy part identification

Products available on this page:

Have Questions About this Product?

The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.

If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.

AT3 Lifetime Warranty Logo

All AT3 Tactical Brand Products carry a lifetime warranty against manufacturer’s defects.

This includes AT3 Red Dot SightsHandguardsIron Sights, and any other product that carries the “AT3 Tactical” or “AT3™” name. For other brands (ex. Magpul or Troy), please refer to the manufacturer’s warranty policy.

In the event that your AT3™ product becomes unusable, we will repair or replace the product at no charge to you.

If we cannot repair your product, we will replace it with a product in perfect working order of equal or better physical condition. The warranty is fully transferable, but we may require information about the original purchase to validate the authenticity of the product.

If your product is in need of warranty service, please contact AT3 Tactical to start the process

Our contact info is available here. To expedite processing, please provide your order information and description of the defect.

Please note: The AT3 Lifetime Warranty does not cover loss, theft, intentional damage or cosmetic damage that doesn’t affect the performance of the product.

Customer Reviews

Based on 83 reviews
Douglas Wilson
Lower parts

Excellent product, fast shipping.

Thanks for sharing your experience, Douglas. We work hard to meet expectations like yours, we're glad we hit the mark for you. Cheers!

Timothy Partington
Fit And function

Parts seem to be no different than any other parts kit I've ever ordered. Everything fit well worked well and the price was right.
Plus It's U.S.A made!

Thanks for sharing your feedback. We're glad you're satisfied with your purchase. Cheers!

william massey

fantastic went in ati polymer lower fit perfect

Looking good! Thanks for choosing AT3, William. We work hard to meet expectations like yours, we're glad we hit the mark for you. Cheers! - AB

Christopher Hall

Kit was exactly and described and shipped quickly just as I was informed. Thank You

Thank you for your positive feedback! We are glad to hear that the AT3 Pro-Builder AR-15 Lower Parts Kit met your expectations and was shipped to you promptly. We appreciate your business and hope you continue to enjoy your purchase. Thank you again!

William Price
AR-15 Lower Parts Kit

AT3™ Pro-Builder AR-15 Lower Parts Kit is a quality mill spec product.

Thank you for your review and for choosing our AT3™ Pro-Builder™ AR-15 Lower Parts Kit. We are glad to hear that you are satisfied with the quality of our product. We strive to provide our customers with the best mill spec products and we are happy to know that we met your expectations. Thank you for your support!