AT3™ Pro-Builder™ Black AR-15 Lower Build Kit
or 4 interest-free payments of $14.87 with 
6 Magazines Per Order: Due to extreme volume, we are limiting sales of magazines to 6 per customer order. This applies to individual and bundled magazines. AT3 reserves the right to cancel any order over the 6 magazine limit.
- Free standard shipping on orders $139+ details
- 90-day no-hassle returns policy
- Backed by the AT3 Lifetime Warranty! what it covers
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Product description
AT3 Tactical Lower Build Kit – Choose Your Own Stock, Grip, and Trigger
This lower build kit includes high quality components to start your next build – and none of the stuff you’ll want to upgrade anyway. This kit includes our Pro-Builder lower parts kit, as well as our Mil-Spec Buffer Tube Kit, providing a solid foundation for your next AR lower. This kit doesn’t include a grip, trigger, or stock – we figure you know what you want better than we do.
If you’re tired of paying for parts you’re just going to throw away before you complete your lower, this is the kit for you. Get what you want out of your next build, without the stuff that’s just going to collect dust in your garage.
Included Components
AT3™ Mil Spec Buffer Tube Kit
- 6 position Mil-Spec buffer tube
- 3oz carbine recoil buffer with T6 anodized aluminum body
- Steel Buffer Spring
- Steel castle nut
- Steel end plate
AT3™ Pro-Builder™ Lower Parts Kit
- 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
Customer reviews 3
Verified buyerAT3 Tactical · Thank you for taking the time to leave a review for our AT3™ Pro-Builder™ Black AR-15 Lower Build Kit. We're glad to hear that you are satisfied with your purchase. If you have any further feedback or questions, please don't hesitate to reach out to us. Happy building!
Questions & Answers 1
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Warranty & returns
Backed by the AT3 Lifetime Warranty!
All AT3 Tactical Brand Products carry a lifetime warranty against manufacturer’s defects.
This includes AT3 Red Dot Sights, Handguards, Iron 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.
90-day no-hassle returns
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.
