Gatling guns as they are now have a rate of fire of about some 600-700? (info from various wikias etc..)
Now apart from a fancy roatating animation that would be a waste of materials since you can get more than double that rof from a single barreled weapon, no need for 6 of them, well apart from more cooling surface after a longer sustained fire.
So i propose you introduce more single barreled weapons such as the german naval Mauser MLG27 (1000-1700 rpm) or maybe a larger 35mm like in the Mantis anti air system (1000rounds per minute)
Now since you alredy have gatlings modeled and ingame I propose you further expand on the gatling guns and add new options such as:
-adjustable rate of fire
-selectable burst lenght
-selectable pause between bursts....etc
The purpose of a gatling gun is to achive a faster rate of fire compared to a single barreled weapon, for example Gau 30 has up to 3900 rpm, M61 vulcan has over 6000 rounds per minute and a 25mm Gau 12 equalizer does some 4200rpm.
I realy think that since this is a futuristic game about engineering it is a litle absurd to think that in the future people would use gatlings for 700 shots per minute when even in the 20th century we had so much faster firing ones.