N18 Overseer Clarification

Not any Heavy Weapon. Not the Rivet Cannon. Which was the only heavy weapon I could get at the time.

I tried that combo with the Rivet Cannon, and in three battles, I was able to fire it twice, and once was a miss.
 
Well, Overseer and Hipshooting Webgun is currently THE MOST broken thing in existence.
FWOOSH and you just ran up 20" into the distance and obliterated any fighter, despite wounds, armour, shields or toughness.
FWOOSH.
So yeah, we made Overseer a one-use Leader ability (for free, take the normal skill) so it's like Warmachine Feat

Especially if your community didn't rule the "Fighter in hiding" rule out (and anything but templates can't shoot at all)