B5 Systems Sierra K Extension Kit, Fits AR15, Black SRK-1660

• Reduced-length 5-position Receiver Extension Constructed of 7075 Aluminum
• Includes a Short Heavy Buffer (3.5 oz), Extra Power Spring, Castle Nut and QD End Plate.

Product Description

The Sierra K Receiver Extension Kit is the proprietary mounting system for the Sierra K Buttstock. All parts are made of mil-spec materials and finishes and proudly Made In The USA.

Specifications