Advanced Hit Efficiency And Destruction (AHEAD) ammunition is a type of airburst round ammunition that releases a cloud of sub-projectiles just ahead of a target, enabling it to engage conventional as well as low, slow and small (LSS) air threats including unmanned aerial vehicles and perform counter rocket, artillery, and mortar duties. The 35 mm variety produced by Oerlikon Contraves splits each projectile into 152 tungsten submunitions "that form a cone-shaped pattern to destroy a target's control surfaces and other vital components". This type of ammunition is listed as an official acronym at the British Ministry of Defence.

The Rheinmetall Oerlikon Millennium Gun or Rheinmetall GDM-008 is a close-in weapon system designed by Rheinmetall Air Defence AG for mounting on ships. It is based on the 35/1000 revolver gun land-based air defense system and uses Advanced Hit Efficiency And Destruction (AHEAD) ammunition.