Wait.. they're using the same caliber as the AC-5??? It's basically A Rotary AC-5 with a different package. Like replacing a shotgun with an SMG.
We don't have any canon fluff specifying 80mm as a caliber used by AC20s, but the round is given for both AC5 and AC10 models, so I'm comfortable with the idea. In the AC20's case, recoil and the resulting 'jitters' of dumping so many rounds so fast introduce the inaccuracies that limit AC20 range.
Revolver autocannons are a real thing, distinct from gatling types. As far as tabletop rules go, the RotaStorm isn't a weapon with any distinctions. It's there so that the LCAF can limit itself to just two ammunition types (LAC 80mm and AC 80mm) and cut down on their headaches.
As long as it's the only source of Omniparts and mech parts, it becomes to juicy to simply kill. Clan's idea of waste (anathema to them) and a right force and trick would bait the clan. (Offer safcon as long as the cap ship did not involve themselves.)
Even in 3025, Finmark is only one of four production sites building Patton hulls. Pods come from at least twice as many locations, and both of those numbers will have increased by the time the Clans show up.