Sprinco AR-15 rifle buffer springs are made from high quality Chrome Silicon wire stock which is used in a variety of applications from Formula One to motor valve springs which can see up to 15,000,000 compression cycles in a single race. This makes it the perfect choice for a rifle which will see far less cycles than that over it’s lifetime. In order for this rifle buffer spring to retain its strength, Sprinco heat treats, shot peens, and treats each spring with a proprietary formula that retains spring efficiency for as long as you have your rifle.