Same here. Heavy gauge coat hangers, a pouch made from an old leather shoe tongue, and six wide rubber bands.When I were a lad, the slingshot of choice was made from a wire coat hanger, much like this one:
The loops on the fork should make at least one twist around the arm to prevent them from opening.
All you needed to make it was a pair of lineman's pliers or needlenose pliers with a cutter.
The rubber band was typically a bunch of wide rubber bands daisy-chained together, for a long pull that did not stress the fork too much.
"Paper ammo"? Hah.
We cut the rest of the coat hanger into 2" lengths and bent them into a "U", therefore no need for a pouch. Fence staples are nice too.
Even so, nobody I know lost an eye.
The perfect design for office warfare.
No one lost an eye, but one friend had his forehead split open from a rock fired out of one.