Depends on the range, heavy gauss is probably going to be rarely used because it uses 11 crit slots and can't be combined with Light Fusion. Also too big to fit in an arm. Also weighs 18 goddamn tons. It's also an even bigger bomb in your ST that you can't crit pad with gauss ammo or heat sinks.
Any way you slice it, Heavy Gauss will need a big range boost to make up for the AC20's superior rate of fire, lower weight, compatibility with LFE and arm mounts, etc. On the tabletop the heavy gauss has almost as much range as a regular gauss rifle, but its damage drops off to 20 and 10 at medium/long ranges. We might see something like 300m but with the old gauss rifle's damage dropoff rate. I don't see the heavy gauss being as much of a game-changer as all the new PPCs and ultra-ACs.
Edited by Luscious Dan, 19 May 2017 - 09:33 AM.