Geissele Super 42 Rifle Length Spring 04-308-F improves an AR-15/AR-10 rifle-length system's function and reliability, built specifically for full-length A2-style buffer tubes rather than the shorter carbine tubes most AR-15 builds use. The Geissele Super 42 Braided Wire Spring uses three independent strands of wire, the same design used by the German MG42 machine gun. That braided design operates like a harmonic damper and energy absorber, letting the strands flex independently from each other. This displaces energy and decreases the risk of spring failure while making the rifle more reliable in the process. Compared to a standard spring, this Geissele Super 42 spring is less likely to lose length and force over time and eliminates the spring reverberations felt through the buttstock. Its return force runs roughly 15% stronger than a standard spring, which helps a Geissele buffer spring strip cartridges from the magazine reliably when the weapon is dirty or running steel case ammunition. Key Features: Three independent strands of wire, MG42-derived design Built specifically for rifle-length buffer tubes Decreased risk of spring failure, enhanced reliability Less likely to lose length and force over time Eliminates spring reverberations felt through the buttstock 15% stronger return force than a standard spring Improved cartridge stripping when dirty or using steel case ammo Not compatible with carbine-length buffer tubes This Geissele Super 42 buffer spring is a straightforward internal upgrade for rifle-length platforms that already have a buffer they're happy with. Geissele Super 42 Rifle Length Spring 04-308-F