CMMG Receiver Extension and Stock Kit – A1, Mk3

Upgrade your precision rifle or heavy AR build with the CMMG Receiver Extension and Stock Kit – A1, Mk3.
This rugged, fixed A1-style stock provides a rock-solid feel, enhanced durability, and a clean, classic look — perfect for Mk3 .308/AR-10 platform rifles.

CMMG — Precision Engineering for Serious Shooters.

Key Features of the CMMG Receiver Extension and Stock Kit – A1, Mk3

The CMMG A1 Stock Kit gives you everything needed for a reliable, no-nonsense stock system:

Fixed A1-Style Stock

• Extended length: Provides a longer length of pull compared to collapsible stocks.

• Traditional design: Ideal for precision shooting and stable prone shooting positions.

Complete Stock Assembly

• Includes receiver extension (buffer tube), stock body, A1 screw, buttplate, sling swivel, and necessary mounting hardware.

• All-in-one solution: No need to piece together parts from different sources.

Built for AR-10 / Mk3 Platforms

• Heavier-duty design: Perfectly sized for larger caliber builds like .308 Winchester and 6.5 Creedmoor.

Why Choose the CMMG A1 Receiver Extension and Stock Kit?

For shooters looking for classic simplicity, durability, and consistent cheek weld, the CMMG A1 Stock Kit is the ideal solution.
Whether you’re building a precision rifle, DMR (Designated Marksman Rifle), or heavy-duty AR, this stock provides unmatched stability.

✅ Perfect for .308/AR-10 platform rifles
✅ Ideal for long-range, stable shooting
✅ Complete kit — no missing parts or extra purchases
✅ CMMG quality — trusted by professionals and enthusiasts

FAQ

Q: Will this fit an AR-15 build?
A: This A1 stock kit is specifically sized for Mk3 / AR-10 platforms. It may not fit standard AR-15 lowers without modification.

Q: Is the buffer and buffer spring included?
A: No — this kit includes the receiver extension tube (buffer tube), stock body, and mounting hardware. Buffer and spring sold separately.

Q: Is installation difficult?
A: No, basic tools and mechanical knowledge are all you need for a simple installation.

Specifications of the CMMG Receiver Extension and Stock Kit – A1, Mk3

• Compatibility: Mk3 / AR-10 / LR-308 Platforms

• Included:

  • Fixed A1-Style Stock

  • Receiver Extension (buffer tube)

  • Sling Swivel

  • Buttplate Assembly

  • Mounting Hardware

• Material: High-strength polymer stock, aluminum buffer tube

• Finish: Matte Black

• Manufacturer: CMMG

• Origin: USA

Build it right from the foundation.
Choose the CMMG A1 Receiver Extension and Stock Kit for your Mk3 rifle and enjoy rock-solid reliability, classic looks, and outstanding shooting performance.
Trust CMMG for your next precision build!