B5 Systems SRK-1660 Sierra K Extension Kit for AR-15, Black

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.

Features:

• 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..

Specifications:

• Type: Buffer Tube Complete Assembly
• Manufacturer Part: SRK-1660
• Model-2: Extension Kit
• Color: Black
• Manufacturer: B5 Systems
• Model: Sierra K
• Sub Category: Stocks & Buffer Tubes