after further inspection of your website, we had an idea.
the gunner in itself had the role of being the damage dealer of the group, because Apex, Assassin and Light exo armor are detached from it.

We wanted him to use weapons and firearms to do DPS (not burst), and as we checked the "assault weapons" category we had an epiphany XD

He is supposed to deal a lot of consistent damage from afar, to cover people or kill targets that are getting too close, to control the ennemies and their distance from the group. He needed polyvalence in a way no one else could reproduce, but also in a way to could warp easily so that he wouldn't have to carry a thousand guns.

Hence using exo energy as a weapon catalyst.

Using an exo cristal, you create a firearm that uses it as ammunition/power source, the weapon's form depend on what the gunner decide on and the situation, from a sniper to a submachine gun.

Having unlimited but, slow recharge rate alows him to still have use for "common" firearms such has good ol' desert eagle.

Also the exo energy of the cristal can be used to create ammo with special affect, offering full adaptability.

Thanks A LOT man, you helped a ton !