Paperclip Bow
If you have a few unbent paperclips and nothing to do with them try this. BTW for ammunition use a few ink cartridges. I do not take blame if you injure someone
Preparation
Take your 2 paperclips and unbend them into 2 straight lines. Bend one into a re-curve shape(like above), and leave the second one alone for now.
Bend the 2 ends of the re-curve paperclip into small open loops (I recommend using pliers).
Take your rubber band and place it in one of the loops and close the loop with pliers.
Twist your rubber band to add tension and while keeping it twisted hook it under the other loop of the paperclip and close it.
Reinforcment
Take your second paperclip and twist it around the first to reinforce it.