SIG Sauer MCX Spear Extended Long Stroke Piston Assembly

Keep your SIG Sauer MCX Spear running at peak reliability with the genuine SIG Sauer Extended Long Stroke Piston (Part #4204140-R). Engineered specifically for the MCX Spear platform, this factory OEM piston assembly is a direct-fit replacement or upgrade component designed to ensure consistent, smooth cycling and long-term operational dependability. Whether you’re a competitive shooter, a serious hunter, or a tactical enthusiast who depends on your MCX Spear in the field, using authentic SIG Sauer components is the best way to maintain the performance and integrity of your firearm.

This extended long stroke piston is built to SIG Sauer’s exacting manufacturing standards, providing proper gas regulation and reliable function across a wide range of ammunition and suppressed or unsuppressed configurations. If you’re restoring, upgrading, or performing routine maintenance on your MCX Spear, this is the genuine part you need.

At Deep Roots Rifle Co, we stock hard-to-find factory components and OEM parts so you can keep your favorite firearms running without the hassle of searching through back-ordered distributors. Order online today for fast shipping nationwide, or stop by our gun shop in Eustis, Florida, where our knowledgeable staff is ready to help you find exactly what your build or repair requires.