The CMMG A1 Receiver Extension and Stock Kit in black synthetic (brand part number 55CA646) bundles everything needed to finish the buttstock end of an AR-platform rifle build in A1 configuration. The kit contains a rifle-length buffer assembly, the correct rifle action spring, and a complete A1 rifle-length fixed buttstock assembly, so builders don’t need to source each piece separately. Pair it with a lower parts kit of choice to complete the lower receiver group. The full kit measures approximately 16.7 inches overall once assembled.

Key Specifications

• Built in A1 rifle-length configuration.
• Uses a fixed (non-adjustable) stock design.
• Includes a rifle buffer assembly.
• Includes the correct rifle action spring.
• Includes a complete A1 rifle-length fixed buttstock assembly.
• Finished in black synthetic.
• Measures approximately 16.7 inches overall once assembled.
• Ships at approximately 1.5 lb.
• Pairs with a lower parts kit to complete the lower receiver group.

Frequently Asked Questions

What’s included in this kit? A rifle buffer assembly, rifle action spring, and a complete A1 rifle-length fixed buttstock assembly.

Do I still need a lower parts kit? Yes, combine this kit with a lower parts kit of your choice to complete the lower receiver group.

Buy the CMMG A1 Receiver Extension and Stock Kit, Fixed, Black Synthetic, for AR-Platform

Finish your A1-configuration build with one matched kit. Order the CMMG kit from our AR braces and stocks selection at our Lubbock, Texas gun shop for fast, direct shipping.