B5 Systems Sierra K Receiver Extension Flat Dark Earth

B5 Systems Sierra K Receiver Extension Features Engineered for a precision fit with the B5 Sierra stock the Sierra K extension offers a shorter length profile ideal for PDW-style builds or low-print applications. Constructed from high-strength materials and coated in a mil-spec FDE finish it ensures smooth cycling consistent lockup and corrosion resistance under harsh field conditions. Whether you're building a compact carbine or updating your duty rifle the Sierra K extension enhances reliability and compatibility while maintaining B5's rugged construction standards. It's compatible only with the B5 Sierra stock line and provides a secure mounting point for buffer tube accessories in SBR or AR pistol configurations. B5 Systems Sierra K Receiver Extension Specifications Manufacturer: B5 Systems Product: Sierra K Receiver Extension Compatibility: B5 Systems Sierra Stock Material: High-Strength Alloy Finish: Flat Dark Earth Application: AR Pistols / Compact Carbines Design: Short-Length Stock-Specific Mounting Style: Standard Threaded Extension Interface