B5 Systems Sierra K extension kit short buffer tube AR15 PDW setup

B5 SYSTEMS SIERRA K RECEIVER EXTENSION KIT

B5 Systems
SKU:
SRK-1660
|
UPC:
814927024793
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Ships within 2-3 business days.
$128.25
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Description

The B5 Systems Sierra K Extension Kit is the proprietary receiver extension system designed specifically for use with the Sierra K stock. Engineered for compact AR builds and PDW-style platforms, this kit provides the foundation needed to achieve a shorter overall length without compromising reliability or performance.

The kit features a reduced-length, MIL-SPEC diameter receiver extension machined from durable 7075 aluminum, offering strength and longevity in demanding conditions. A 5-position adjustment system allows for flexible length-of-pull settings while maintaining a compact footprint.

Included in the kit is a short heavy buffer (3.5 oz) and an extra power spring, optimized to ensure reliable cycling in short-barreled and compact configurations. The system is completed with a castle nut and QD end plate, providing secure installation and integrated sling attachment capability.

Built with MIL-SPEC materials and finishes and proudly made in the USA, the Sierra K Extension Kit is an essential component for maximizing the performance and functionality of the Sierra K stock system.

Kit Includes:

  • 7075 Aluminum Reduced-Length Receiver Extension (MIL-SPEC Diameter)
  • 5-Position Adjustment System
  • Short Heavy Buffer (3.5 oz)
  • Extra Power Buffer Spring
  • Castle Nut
  • QD End Plate