UTG PRO S1 Mil-Spec AR-15 Buttstock Kit - All Parts Included - Buffer, Tube, Springs, & More
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From orders that included this itemProduct description
UTG Pro S1 AR-15 Stock Kit – Complete Mil-Spec 6-Position Recoil System
Features
- Complete AR-15 carbine stock kit with stock, receiver extension, buffer, spring, end plate, and castle nut
- Six-position mil-spec receiver extension provides adjustable length of pull
- S1 polymer stock features a rubberized butt pad and slanted cheek rest
- Dual waterproof storage compartments accommodate up to eight CR123 batteries or other small accessories
- Integral ambidextrous sling loop and QD sling swivel housing provide multiple sling attachment options
- Chamfered edges and rounded contours help reduce snag points
- Available in Black and Flat Dark Earth
- Designed and made in the USA
The UTG Pro S1 Stock Kit includes the components needed to add a complete carbine-length recoil system and adjustable stock to an AR-15 lower receiver. The full-size S1 stock provides a broad cheek rest, rubberized butt pad, and dual waterproof storage tubes, while the six-position mil-spec receiver extension allows the length of pull to be adjusted from 11.3″ to 14.6″. Black and FDE versions use the same components, with the FDE kit featuring a matching FDE Cerakote receiver extension.
Note: This kit includes an AR-15 carbine buffer and spring. It is not a complete AR-308 recoil system.
Specifications
- Brand: UTG Pro
- Model: Ops Ready S1 Mil-Spec Stock Kit
- Compatibility: AR-15
- Stock Positions: 6
- Receiver Extension: Mil-spec diameter, 6061-T6 aluminum
- Stock Material: High-strength polymer
- Buffer: Standard carbine, 3.0 oz
- Storage: Dual waterproof compartments, up to 8 CR123 batteries total
- Stock Dimensions: 8.1″ long x 2.2″ wide x 5.5″ high
- Length of Pull: 11.3″ collapsed to 14.6″ extended
- LOP Adjustment Increment: 0.625″
- Kit Weight: 23.1 oz
- Castle Nut Torque: 35-40 ft-lb
- Color, Finish & MPN:
- Black: RBUS1BM – Black anodized receiver extension
- Flat Dark Earth: RBUS1DM – FDE Cerakote receiver extension
- Country of Origin: USA
What’s Included
- 1x UTG Pro S1 stock
- 1x Mil-spec 6-position receiver extension
- 1x Standard 3.0 oz carbine buffer
- 1x Carbine buffer spring
- 1x Tear-drop receiver end plate
- 1x Castle nut
All 1 options on this page
Customer reviews 5
AT3 Tactical · Thank you for taking the time to leave a review for our UTG PRO S1 Mil-Spec AR 15 Buttstock Kit. We are glad to hear that you were satisfied with all the included parts, including the buffer, tube, and springs. We strive to provide our customers with high-quality products that meet their needs. If you have any further feedback or questions, please don't hesitate to reach out to us.
AT3 Tactical · Thanks for sharing your feedback! We're glad you're satisfied with your purchase.
AT3 Tactical · Thanks for sharing your feedback! We're glad you're satisfied with your purchase.
AT3 Tactical · Thanks for sharing your feedback! We're glad you're satisfied with your purchase.
Questions & Answers
No questions yet. Ask about fit, install or compatibility and our team answers within a business day.
Warranty & returns
Backed by the UTG Lifetime Warranty!
UTG Lifetime Warranty
Leapers, Inc. warrants that all UTG & UTG PRO products conform to published specifications and are free from defects in material and workmanship. We will repair or replace defective products for the duration of the product’s life span. Our dedicated in-house customer service professionals will provide the best-in-class UTG experience.
Please note that this warranty does not extend to products disassembled, damaged from misuse, accidental impact, negligence, natural disasters/accidents, or unauthorized repair or alteration.
Warranty Instructions
- Go to Warranty Request under Customer Service on our website.
- Fill out the necessary contact and product information to the best of your knowledge.
- A purchase receipt is required for all warranty cases and needs to be attached at the end of the form.
- Finalize the case by submitting the information to us.
- You will hear from one of our customer service reps within 24-48 hours and we will provide you with additional information and instructions.
- No return will be accepted without an RA#.
- For any questions regarding the process, please feel free to call at (734)542-1500.
Disclaimer: Manufacturer’s warranty is subject to change without prior notice.
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.

















