no as in how do they actually reload? how do the bullets get into the magazine from the tank. sorry for any confusion.
I guess there is a loader or loading mechanism in the tank. If that does not suit you Nanites or redeploying. Maybe both.
Nanites. You could assume that the secondary's mags already have all of the bullets in them, they just have a.. jam checker (yum)? overheating barrel that needs to cool for 3 seconds? If you look at the Prowler's Vulcan, it should have far more than 30 bullets in its mags considering the size of the belt feed. But then if you look at the underbelly of the Reaver with its Vortek equipped, that belt feed isn't fed from the aircraft; there's a noticeable gap between the aircraft and the gun. Solution? Nanites.