M4 Carbine/6.8 Cs Spring Kit - Spring Kit-Xp Buffer &Enhanced 4coil Bolt Extractor Spring

Extra Power Buffer Spring. This was Sprinco's first AR buffer spring solution that they were tasked to design back in 2006 for a Force Modernization Team to specifically address spring-related M4 carbine reliability function issues for operating challenges in the Eastern Asia Theatre. The design loads of the Red spring are approximately 25% greater than the White spring for one of the considered Load Constants in the spring design. Refer to provided tuning procedure reference documents prior to