5.56 NATO 64GR Federal Tactical Bonded Soft Point (XF556T64X)5. 56 NATO 64GR Federal Tactical Bonded Soft Point (XF556T64X) uses Federal's Flux Bonded bullet technology that has led the market since 1995. In response to American law enforcements need for rifle bullets which held together after being shot through glass, Federal introduced this bullet technology commonly used in rounds like Tactical Bonded, Trophy Bonded, Trophy Bonded Tipped, and Terminal Ascent. This 64 grain self defense round ((XF556T64X)