So, by RAW, a regiment can have Autocannons as their Favored Heavy Weapon. Heavy Gunners can choose to start with a Favored Heavy Weapon. While I'm sure the party isn't complaining (3d10+8 I Pen 6, fired at 3 round Semi-Auto is nothing to sniff at), I'm not entirely sure this should be possible. The autocannon blows the HG's other weapon choices (heavy stubber or missile launcher with frag missiles) out of the water.
Hell, the "super awesome" choice every group I've seen use so far has been the Heavy Bolter, with a respectable 1d10+8 X Pen 5 six round Full Auto and Tearing, but this still trumps it by a long shot. The only choice I see competing with the Autocannon would be the Multi-laser (2d10+10 E, Pen 2) but even that falls behind a little.
Thoughts?