“RED Spring” EXTRA Power Buffer Spring, Best option for 16"+ 5.56 barrels with carbine length gas system platforms with standard front sight towers and H buffers, 16" + BBL gas piston guns, *some* suppressed shorties,and later generation Colt LE6920's, 9mm, 6.8 SPC, 6.5 Grendel, .458 SOCOM, 450 Bushmaster, .500 Beowulf, and assorted "Thumpers" using standard 7" depth M4 extension tubes. AR-10 Carbines (E.G. Armalite, Noveske, LMT) using deeper extension tubes and standard length carbine buffers to accommodate the longer .308 BCG also use the "RED" Spring. RIFLE length extension tube platforms. Color Coded RED. NOTE: NOT for use in .308 Carbines using standard 7" M4 extension tubes and short, stubby buffers. (Use our "ORANGE Spring" NOTE: If you have a seriously overgassed .308 Carbine which has the deeper AR-10 platform receiver extension tube running an H3 buffer firing 175 Gr. Projectiles and / or suppressed, many shooters have experienced success using the "ORANGE" spring, as it is still heavier than a "RED" spring in that application.
Tactical Springs LLC M4 / CAR-15 EXTRA POWER Moly-Plated Chrome Silicon CARBINE Buffer Spring in Hard Tube (Color Coded RED)