B5 Systems AR-15 Sierra K Mini Buffer Kit - SRK-1660

B5 Systems AR-15 Sierra K Mini Buffer Kit

Purpose-built for compact performance.

The B5 Systems Sierra K Mini Buffer Kit is a compact buffer system designed specifically for the Sierra K buttstock. It features a reduced-length 5-position receiver extension machined from 7075-T6 aluminum, along with a 3.5 oz short heavy buffer, extra power buffer spring, QD end plate, and castle nut.

This kit provides smoother cycling and enhanced reliability for compact builds like SBRs and AR pistols. Its streamlined design installs directly onto any mil-spec buffer tube-compatible lower with no modifications required, making it an ideal upgrade for shooters running the Sierra K stock on .223/5.56 platforms.

Features

• 5-position reduced-length receiver extension (mil-spec diameter)
• 3.5 oz short heavy buffer for improved recoil management
• Extra power buffer spring for enhanced cycling performance
• Quick detach (QD) end plate for sling attachment
• Compatible with mil-spec AR-15 lowers and the B5 Sierra K buttstock
• Includes buffer tube, spring, buffer, end plate, and castle nut

Specifications

• Buffer Weight: 3.5 oz
• Material: 7075-T6 Aluminum (extension tube)
• Adjustment Positions: 5
• Application: AR-15 (.223/5.56)
• Compatibility: B5 Sierra K stock
• Total Weight: Approx. 16 oz
• Origin: Made in the USA