This gun is modeled after the Russian diminutive of the famous American M61 Vulcan 6-barrel rotary gun, which was used in Mil MI-24 battlefield helicopters. The turret has pretty limited arcs of fire (-21..+26 degrees vertically and -30..+30 degrees horizontally), but this was the price to keep it compact. Belt of 12.7mm (0.5in) ammo is modeled with motorcycle chain parts (Note: In Lego Digital Designer, this type of chain cannot be twisted, but it tolerates that pretty well in reality). To save space, I omitted parts of gun behind its rotor (151): bolts, springs, catches, etc. Gun turret can be controlled with joystick from cockpit through laying pushrod (152), which rotates trunnion directly. Training is made by training pushrod (153) rotating training lever (7), which drives training transmission gear (105) through rotating axis of trunnion. Gear (104) rotates training gear of gun (105). Behind fixing hardpoints of turret (154) there is a magazine for belt of 100 rounds (106). Belt is extracted from magazine by extractor gear (155) and received at gun by receiver gear (5), which is driven by gun rotor (151). This type of gun has firing rate of 4000 shots/min in the reality, so it can empty the whole magazine in a 1.5 second-burst, but I had no more space for magazine, and motorcycle chain is not very compact.