With a double barrel system, the gun can keep a sustained fire for a longer time.

Change the fire mechanism to alternate between left and right gun.
Maybe make them all semi-auto, then add some shit like the FRT to make it fire faster and alternate between left and right gun.

Give dual drum mags to the operator. One will have to be mirrored to the other side.

Advantages:
Entire team can share ammo with guy.
Improved logistics as the barrel and other parts are all the same.