how about making the other AC versions overheat after a while be their disadvantage?
that way you have more firepower but have to watch your heat bar (which can simply be those yellow bars on the crosshair filling up with red a bit after each shot)
I may try that later on, but right now I'm thinking of making the standard AC be like an HE round where it will explode at the point where you clicked to have the possibility of destroying multiple enemies at the same time.
Nah that doesn't feel right. How about making HVAC shoot through elementals and (maybe) one-shot golems. Regular AC bonus should be: cheap, doesn't overheat (and if you plan to add ammo - cheap ammo). RAC just has über rate of fire, but should overheat and jam quickly. LBX - make pallets spread out so they can hit multiple enemies, but also make one Elemental requite 2 pellets to be killed (3-4 for Golem) and reduce ROF. UAC - faster firing AC with a tendency to overheat after a moderate time.
Just my input, hope you like it.