These heavier AR-15/M16 buffers assist in improving reliability in rifles with a shorter gas system. Heavier weight also assists in reducing bolt bounce in full auto fire. An added benefit, is a slight reduction in felt recoil.
AR-15, Issue:11, Page:032
Big Book Catalog, Issue:69, Page:031
SPECS: Fits - AR-15/M16 rifles and carbines. Heavy weight - 3.55 oz.