Mac 10/11 Recoil Buffer ™. The Buffer Technologies Recoil Buffer ™ for the Mac 10 and 11 replaces the original factory part. The buffers are an easy and inexpensive way to eliminate damage of critical components by preventing the metal to metal contact of the slide, or breech block with the frame. Made from a high density polyurethane formulated for maximum shock-absorbing characteristics, the recoil buffer is a drop-in part.