What would be the price of a transforming weapon?

[WaterAndWindSpirit]

So I've been looking at the D20 Modern SRD for good FX items to convert, and I was thinking that a weapon that can change shape, called a bladegun, would be nice.

Basically, a weapon that could transform from one form to another, like a sword that could turn into a FAMAS, or a baseball bat that could turn into a compound repeating crossbow, where both weapons would have the same magical properties, but act like they normally would in the form you have them turned into (so no parrying with a gun unless you want to ruin it, and no shooting with a sword), and changing forms takes a Concentrate maneuver on part of the wielder.

Also, would it be possible to turn an existing magic item into a transforming weapon into a bladegun? How much would it cost?

[Anaraxes]

Payload seems like the simple method. Uses a Ready Maneuver to swap rather than Concentrate, though. (If the small differences there are important, you might get away with adding "Requires Concentrate".) Add the +50% Cosmic to make it extra-dimensional hammerspace if you want to be sure the inactive weapon is undetectable. The fact that you're "transforming" one weapon into another rather than stashing one and retrieving another is mostly just fluff, though you might want to rule that damage or loss affects the inactive weapon as well.

[Refplace]

Originally Posted by Anaraxes

Payload seems like the simple method.

Really good idea!
I would add to that a perk for each weapon to allow a single Fast Draw skill to apply to any of them.
And gadget limitations if ts the weapons ability.

[WaterAndWindSpirit]

I may have been unclear. My bad.

I wanted to know the energy cost you would put on enchanting a weapon to be a bladegun. I want to do it as equipment, not as character abilities.

[Anaraxes]

Well, a fairly literal translation of the Payload notion in GURPS Magic terms is to make the blade a Hideaway big enough for the gun, while the gun is enchanted with enough Hideaway to hold the blade. (Basically 100 energy * the sum of the weapon weights.)

One round of Ready is reasonable to find something if it's the only thing in a small Hideaway; I'd probably let the outside one get stashed as part of the same action.

A Fast-Draw (Bladegun) skill sounds like a good thing for a character to pick up, if you want to allow that. Since it's supposed to be a magical transformation, and not really stashing one object inside another, you might want to decide that the change just takes as long as it takes.

I'd write it up as a new Enchantment spell, with a prereq of Hideaway. The enchantment would require the two items both to be present for the ritual, and only those two items would be linked to change into each other. (A double Hideaway, taken literally, would let any third object, or a third and forth, be stored in the first two, which we don't want, nor can you just replace the blade or gun component with a new upgrade without redoing the enchantment. This restriction is mostly to fit the fluff, but I'm happy to have a small drawback to balance out the benefit from the faster swap.)