These Tubb SpeedLock Systems high quality carbon silicon springs are heat treated, stress relieved and shot peened. The result is a durable, consistent spring that will increase the functionality of your gun. Due to the superior nature of its material, Tubb CS springs have the same power as a conventional "extra power" spring, yet provide that extra striking energy using a lighter spring weight. This ensures reliable ignition while minimizing sear pressure and bolt lift effort, resulting in a more consistent, durable trigger pull and smoother rifle operation.