Experience enhanced performance with the Gen 2 drop-in captured spring recoil system for your AR, providing a smoother and quieter operation without any permanent modifications. The JP LMOS buffer and custom-ground buffer spring work in tandem to drastically reduce friction and vibration, removing the annoying noise typically produced by conventional springs and buffers. The system fits both M4 style collapsible stock buffer tubes and, with the included spacer, longer tubes for fixed rifle stocks. The H2 buffer, weighing approximately 4.7 oz, includes two Tungsten weights and one steel weight, making it ideal for short-barreled rifles, suppressed firearms, select fire rifles and piston-operated rifles. Additionally, the Auxiliary spring Rate kits allow for fine-tuning to ensure optimized performance for various configurations, especially rifles without adjustable gas blocks. The newly designed aluminum guide rod reduces the overall weight Increased mass results in greater buffering capacity and a higher likelihood of bolt bounce Complete correspondence exists between SCS masses and the H1, H2 and H3 buffers