The CMMG Fixed A1 Stock Kit (brand part no. 38CA964) bundles everything needed to complete the buttstock end of a CMMG MK3 .308 build in one polymer-and-aluminum package finished in black matte. CMMG pairs an A1-length receiver extension with a matched .308 rifle buffer assembly and action spring so the whole system is tuned for reliable cycling in the larger .308 platform, not just adapted from a 5.56 parts bin. Combine this kit with the lower parts kit of your choice to finish out your MK3 lower.

Key Specifications

• Includes a CMMG A1 receiver extension sized for the MK3 .308 platform.
• Ships with a matched .308 rifle buffer assembly for correct cycling weight.
• Includes a .308 rifle action spring tuned to the heavier buffer.
• Completed with an A1 rifle-length buttstock assembly, fixed (non-collapsing) design.
• Built from polymer and aluminum components for a durable, mil-inspired fit and finish.
• Finished in black matte to match most MK3 builds.

Frequently Asked Questions

What does this kit include? A CMMG A1 receiver extension, .308 rifle buffer assembly, .308 rifle action spring, and A1 rifle-length buttstock assembly.

Does this kit include the lower parts kit? No, combine it with the lower parts kit of your choice to complete the lower.

Is this a collapsible or fixed stock? Fixed A1-length, not adjustable.

Buy the CMMG Fixed A1 Stock Kit

Finish out your CMMG MK3 .308 build with a receiver extension, buffer, spring, and stock matched for the platform. Order it from our AR braces and stocks selection at our Lubbock, Texas gun shop for fast, direct shipping.