I have several power packs collected in my inventory, and, since they are supposed to go in one of the secondary slots, I guess they are ammo for something, but what?
I'm fairly far along in the game (ready for Mount Gigas), but these items don't seem to apply to any weapon I've come across. Can anyone enlighten me? Thanks!
Ginger

There are some modern weapons you can find that will use them; really though I find those are a waste, there's alot less ammo then there is out there for bows/slings to the point where there's no use in building the modern weapons skill, and the bow type weapons are better anyways. The only character who should use modern weapons is the Gadgeteer, and he should stick to his omnigun. I think the flamethower is one of the modern weapons that uses power packs? But I would just sell them, they're not worth their weight ;)

vapouriser need powerpack. but it doesn't do much damage though, so better sell them.

For example, the frontier phaser uses power packs.
But you can continue to shoot when they are gone.
Saves on ammo weight.

Yeah, phasers need packs,don't think vaporizers [which cast boiling blood, does lots of damage] do: don't remember ever reloading them...

Oru

Vaporizors are ready-made gadgets that you see a lot of when trying to get a light sword. They cast instant death and do not require powerpacks