In real life, it would have to be motorized, battery powered, like the real mini-guns. Not even the gatling guns of the old west were turned by the recoil. I thought about using the recoil to move it, but it isn't feesible. you would want the most time from shot fired to fired again, and you could only use the top for loading, and the bottom for extraction. Even if you made the very next chamber from loading the firing chamber, you would be slowed by the action cycling to cock the action, and move the barrels. I figure you can do it, like the revolvers they showed on the history of the gun, where the cylinders are zig zag patterned, so that the recoil would force the spin. But I don't think you could get the speed. I am guessing at best maybe 1000 rds per. Even if you shortened the gas return. But maybe that is good enough.