The JP Silent Captured Recoil spring assembly is a self-contained unit that replaces the standard buffer and spring. The components of the assembly are highly polished for extremely smooth and quiet operation. The system is optimized for use with a JP Low mass bolt carrier and adjustable gas system, but also works with standard weight components. The system is designed to work with a carbine length buffer tube, and includes a spacer for use in A1/ A2 fixed stocks. The spring is also removable for custom tuning for your rifle. This captured recoil spring assembly is designed to eliminate the noise and vibration of the standard buffer, spring, and buffer tube. When used with a tuned gas system, this captured spring and buffer dramatically reduce the feel of the mechanical recoil of a standard system, making it feel more like a bolt gun.