I briefly head something on the fireside about a dual mode gun suggested. I am not sure exactly what it was, but this is my take on it.
You have a large skeet thrower that flings large disks. They are somewhat like unarmed mines in a disc shape, but with a more flat flight arc (like a Frisbee). They do little to no damage if they hit a target. The secondary of the weapon is a small accurate shotgun that also does little damage to a target, likely a bit of piercing and fire, with a good chance of starting fires. However, if the light gun hits the large skeet, it creates a spectacular explosion that damages all ships around it.
The small gun would use piercing incendiary slugs to penetrate and ignite/trigger the target disc.
Other guns that have piercing and fire starting abilities would also trigger the explosion. This would include Hades by default, and Gatling or Merc with incendiary rounds. This would add an interesting, even higher skill effect since the skeet would actually fly further than its onboard gun could shoot. You could fire a disk, then shoot it down with incend Merc. Or, if you are unlucky, it could be shot by an enemy just as it launches with incendairy Gat and explode your own ship.
It effect, this would be a high skill, high risk, high reward large version of the mine launcher.