JP Enterprises Silent Capture System is a self-contained buffer system that reduces recoil, smooths out the operation of the rifle, and gets rid of the cheese grater sound of the old buffer and spring. These are the best investment I have ever made to a rifle that I already own or in the process of building.
Includes spacer to allow for installation in both carbine and rifle-length buffer tubes.  These are recommended for AR-15's that use standard weight buffers.  Does not work with PWS bolt carriers