Fornes Gear Gun.
Interesting design by an argentine inventor. This gun externally powered by an small electric motor fires at 5000 to 6000 rounds per minute with a single barrel.
The advantages over a gatling type are less bulk, weight, and low power consumption ( 15 % of a gatling equivalent) The cartrigde remain always coaxial to the barrel between the loading , firing and expulsion, and does not have any reprocicating movement.
Disadvantage is a notable overheating of the barrel in long burst wich probably would work better with water cooling.
Attemps by the inventor ( Javier Fornes, from Mendoza) to sell and develop a 20 /30 mm variant with the budgetary cooperation of the Argentine military has been unsuccesful so far.
3D animation of components and function
http://www.youtube.com/watch?v=4xD0v5w1HOw
.38 special prototype firing