AR-15 Buffer Tail CapReplacement tail cap for your AR buffer. Also referred to as the bumper, buffer tip or plug. The wedge shaped synthetic tail cap, or tip, located at the rear of your AR's recoil buffer is designed to withstand thousands of rounds. However, its longevity can be compromised by factors that increase the frequency or force of its impact against the rear of the receiver extension. Initially, the buffer tail's outer diameter closely matches that of the