I was a bit unimpressed by the stats written for the termie's assault cannon. I mean, they aren't all that much different than the heavy bolter. While the description of the weapon uses the word "explosive" regarding the ammunition, the damage is listed as impact. I always though (probably in error) that it fired bolt rounds. The rate of fire is also unimpressive for a weapon with several spinning barrels that is supposed to chew infantry into pudding.
Now I don't want to unbalance the game, but such a top-tier weapon should at least be worthy of it's renown/aquisition requirements. I'm going to house rule that the assault cannon has the Storm property to reflect its high rate of fire. What do all of you think of this? Should it be beefed up even more? Should it have explosive damage like a bolt or maybe higher piercing?