Did you seriously multiply the damage that the biggest ISBA gauss weapon does by six? And it does as much damage as a 'mech scale *gauss rifle?* Jeez.
Intriguing idea, and I could likely rationalize it based on following the patterns of 'Mech based gauss rifles and basing on the Magshot, but you know what? I'm gonna go out on a limb and say "no," and not even because it's unbalanced (which I feel it is, with that kind of damage bump), but because it doesn't make *sense.*
Where is the incremental increase from a 175kg magshot to a 350kg supergauss? Where is the scaled damage over ranged, a quality I would assume this monstrosity would share with the Heavy Gauss, since it's less about getting a small projectile to RIDICULOUS SPEED (forgive the shouting), and more about getting a large projectile moving fast, a sort of high muzzle velocity AC/20. (that's how I envision it anyway.)
In short, how did they *get* there?
Having just played the part of the "hells, no" crowd, however, let me provide an alternative possibility- The Clan BA based HAG-10. You'd have to pay through the nose for ammo, since those things are always ammo-hogs, since they're basically vulcan-gausses, yes? And at least the clans have a history of building "Smaller, more efficient, more miniturization," Whereas the Lyrans have a history of over-engineering their 'tech, which is what made the HGauss a possibility for them.
Use your existing stats, make it 10 damage, apply all the standard mods for HAGs, drop it to 900 kilos or so for the firing mechanism, and make each shot 50 kilos (since each burst of firing is about 50 1kg slugs), and I think you might have something that makes sense. And doesn't cluster head-cappers.
Bear in mind, what you do in your game is fine. But this really does make more sense to me.
