I created a Rock-It Launcher before doing the quest 'Those!' fighting the fire ants. The launcher worked perfectly and murdered the crap out of fire ants in Grayditch and all throughout the Marigold Metro station. Towards the end, however, I swapped weapons while the launcher was equipped (to the shishkebab IIRC) and now whenever I equip the launcher it shows 0/0 ammo. If I reload it DOES show about 15 objects in the hopper.
What makes this seem like a new bug is the fact that when I fire, the Rock-It launcher DOES fire an object! And it deals damage. But the bug is that after each and every object fired, the launcher does an odd 'reload' animation - it looks kinda like the 9mm pistol reload animation, in that you see your character's hand slap the grip of the weapon then do something with the top of the launcher.
(I searched through the forum and did see other bugs with the rock-it launcher but not quite like this one, which made me think it was worth bringing up.)