Abstract: A stabilizing device for a gun comprising a gyroscope and a mounting assembly attached to the gyroscope for resiliently connecting the gyroscope to a gun. The mounting assembly has a gyroscope slide carriage and a first resilient member connected to the gyroscope slide carriage. The first resilient member allows the gyroscope slide carriage to move longitudinally relative to the gun. A second resilient member is interconnected to the first resilient member and to the gyroscope slide carriage. The second resilient member allows the gyroscope slide carriage to move transverse to the longitudinal axis of the gun. The first resilient member includes a pneumatic cylinder, a piston slidably received within the pneumatic cylinder, and a piston rod connected to the piston at one end and to the gyroscope slide carriage at the other end. The mounting assembly further includes a fixed frame member, a pivot frame member, and a slide rod affixed to and extending between the fixed frame member and the pivot frame member.