
Availability: In Stock
The CMMG AR-15 A1 receiver extension and stock kit gives you the core components needed to complete an AR-15 lower build with classic A1-style ergonomics. Whether you're assembling a retro rifle, a practical utility build, or just need a reliable fixed stock setup, this kit bundles the essential parts—receiver extension tube, buffer, recoil spring, and A1 fixed stock—so you're not hunting down pieces separately. It's the straightforward approach to finishing your lower group: pair this with a lower parts kit of your choice and you've got a solid foundation.
The A1 fixed stock has been the standard for decades. It doesn't collapse or fold, which means no moving parts to wear, rattle, or complicate maintenance. For shooters who run a fixed setup by choice—whether for reliability, weight savings, or simply preference—this kit delivers without fuss. The rifle-length tube and components are sized for a standard rifle build, so compatibility with standard AR-15 lowers is straightforward.
CMMG parts are made to work. This kit comes complete with the receiver extension tube, end cap, recoil spring, buffer, stock, and stock screw, so assembly is a matter of fitting it into your lower and tightening down. No surprises, no missing pieces. It's the kind of no-nonsense component set that works just as well on a range rifle as it does on a hunting or duty build.
| Brand | CMMG |
| Product Type | Receiver Extension & Stock Kit |
| Style | A1 Fixed Stock |
| Tube Length | Rifle |
| Color | Black |
| Included Components | Receiver extension tube, end cap, recoil spring, buffer, A1 stock, stock screw |
Yes, this kit is designed for standard AR-15 lower receivers. Pair it with a lower parts kit of your choice to complete your lower group assembly.
The kit comes complete: receiver extension tube, end cap, recoil spring, buffer, A1 fixed stock, and stock screw. Everything you need to attach it to your finished lower.
The A1 stock is fixed—it does not collapse or adjust. This provides a solid, maintenance-free design with no moving parts on the stock itself.
The receiver extension (also called a buffer tube) is the tube that runs along the rear of the rifle and houses the recoil spring and buffer. It's the mechanical foundation that the stock attaches to, absorbing recoil energy and allowing the bolt carrier group to cycle. It's essential for any complete AR-15 build.


SKU: 115667846 • Width: 6in • Height: 1.7in • Depth: 15.2in • Weight: 1.44oz
Availability: In Stock
The CMMG AR-15 A1 receiver extension and stock kit gives you the core components needed to complete an AR-15 lower build with classic A1-style ergonomics. Whether you're assembling a retro rifle, a practical utility build, or just need a reliable fixed stock setup, this kit bundles the essential parts—receiver extension tube, buffer, recoil spring, and A1 fixed stock—so you're not hunting down pieces separately. It's the straightforward approach to finishing your lower group: pair this with a lower parts kit of your choice and you've got a solid foundation.
The A1 fixed stock has been the standard for decades. It doesn't collapse or fold, which means no moving parts to wear, rattle, or complicate maintenance. For shooters who run a fixed setup by choice—whether for reliability, weight savings, or simply preference—this kit delivers without fuss. The rifle-length tube and components are sized for a standard rifle build, so compatibility with standard AR-15 lowers is straightforward.
CMMG parts are made to work. This kit comes complete with the receiver extension tube, end cap, recoil spring, buffer, stock, and stock screw, so assembly is a matter of fitting it into your lower and tightening down. No surprises, no missing pieces. It's the kind of no-nonsense component set that works just as well on a range rifle as it does on a hunting or duty build.
| Brand | CMMG |
| Product Type | Receiver Extension & Stock Kit |
| Style | A1 Fixed Stock |
| Tube Length | Rifle |
| Color | Black |
| Included Components | Receiver extension tube, end cap, recoil spring, buffer, A1 stock, stock screw |
Yes, this kit is designed for standard AR-15 lower receivers. Pair it with a lower parts kit of your choice to complete your lower group assembly.
The kit comes complete: receiver extension tube, end cap, recoil spring, buffer, A1 fixed stock, and stock screw. Everything you need to attach it to your finished lower.
The A1 stock is fixed—it does not collapse or adjust. This provides a solid, maintenance-free design with no moving parts on the stock itself.
The receiver extension (also called a buffer tube) is the tube that runs along the rear of the rifle and houses the recoil spring and buffer. It's the mechanical foundation that the stock attaches to, absorbing recoil energy and allowing the bolt carrier group to cycle. It's essential for any complete AR-15 build.
SKU: 115667846 • Width: 6in • Height: 1.7in • Depth: 15.2in • Weight: 1.44oz

