Since this is supposed to be the Assault Cannon from TFC and Quake TF, I've decided to make some stats that are supposed to reflect how the Assault Cannon works in those games:

25% more pellets per shot
+525% more secondary ammo in reserve
30% faster spinup time
Can cancel spindown animation by switching to secondary or melee
Cannot spin up with secondary fire
Uses secondary ammo instead of primary ammo
30% less damage