Gun Construction Kit or similar resources?

[Dwarf99]

Originally Posted by PTTG

And now we're full circle back to 3ed vehicles.

Perhaps I should have clarified that there's tables in 4th edition Spaceships that do energy output in kJ and don't require any math. Just look at the table column that has cm corresponding to your gun's mm. A side note: Alternate GURPS 2 presents a different table based on the square rather than the cube.

Actually, I've been writing this stuff out and what I'm finding is that for my purposes, I'm going to have PCs build their weapons as innate attacks.

I am doing that for my game, but it's TL 3+5 so the only firearms are Metatronic Generators.