Ar-15 Carbine Flat Wire Spring

The SI Carbine Flatwire Spring is an economical, easy upgrade to any AR system with a carbine buffer system. The flatwire spring increases service life of the platform, smooths out the shooting cycle, and greatly outlasts the stock spring. Increased bolt load, in addition to decreased compression force increases reliability in cycling. Additionally, all SI Flatwire springs are cryogenically stress relieved to provide greater consistency, longer spring life, and greater resilience to high cycl