For everyone that likes Warhammer 40k Tabletop and Dawn of War Games or anything to do with Warhammer 40K.
Space Marine Plasma Blaster as they didn't have Assault Cannon's back in the the 30K Era.
Dark Angels should have a few lying around.
Also the other weapon is just a Power Axe.
So the AdMech put a Plasma Gun on your Plasma Gun so you can plasma while you plasma.
Also this weapon isn't just something Forge World made up for the Horus Heresy series.
Wh40k.lexicanum.com
**** YEAH I DO LIKE PLASMA GUNZZZ!!!
unlike this guy Moddb.com