Aboard USS Curtis Wilbur (DDG 54) Oct. 29, 2001 -- Mark 45, 5 inch, 54-caliber forward gun mount performs a âPre-Aimedâ and Calibrate (PAC Fire) exercise aboard the guided missile destroyer. Curtis Wilbur is conducting missions in support of Operation Enduring Freedom. U.S. Navy photo by Photographer's Mate 1st Class Ted Banks. (RELEASED)