The Air Force requires engineering services to assist with maintenance, testing, research, engineering investigations, configuration management, technical data, design and manufacturing, prototype design & production, and related issues regarding medium caliber aircraft guns. The primary focuses of this effort is for the 20mm M61A1/A2 used on the F16, F-15, F-18, F-22, and F-15E aircraft and the 30mm GAU-8 used on the A-10 aircraft. These are high rate of fire weapons fixed mounted on the aircraft designed to suppress or incapacitate aerial or ground targets. The primary purpose of this task is to provide engineering services for this medium caliber gun and ammunition feed system to maintain and improve weapon system reliability, maintainability, and supportability. As the original designer, current developer, and manufacturer of all modern high rate of fire rotary gun systems, General Dynamics is still the only viable source for this engineering services contract. This requirement is sole source to: General Dynamics-OTS, Inc., 326 IBM Road Building 862 Williston, VT, 05495-7907. GAGE: 05606. Authority: 10 U.S.C.2304(c)(1) as implemented by FAR 6.302-1, Only One Responsible Source, and No Other Supplies or Services Will Satisfy Agency Requirements.