The cannon has a sliding housing for the front of the barrel and there are slots cut in the barrel for a through bolt, which holds a 6-32 swivel link. Two machined Aluminum supports for the bolt were added to match the external appearance of the cannon and locate the bolt as it slides through the slot. A threaded rod connects the through bolt swivel link to a second link that is attached to the recoil servo arm. The servo has a high strength Aluminum hub and a brass arm is bolted to this. As the servo arm rotates the sliding housing moves forward and back.