A vibration problem with the Orbital/ ATK GAU-23/A 30mm cannon fitted to Air Force Special Operations Command’s AC-130J Ghostrider aircraft was identified in the FY2017 report by the Office of the Director, Operational Test and Evaluation.
The GAU-23/A’s recoil caused mount vibration problems that led to it having to cease fire and point away from its target and return to its bore-sighted position. This issue had not been encountered by the same weapon when mounted on AC-130W Stinger IIs.
The report recommended that changes to the fire control system be made to solve the problem, rather than altering the mount and weapon. David C Isby