This is technically a crossbow, but it's used as a pistol. It's a crossbow because there is no ram, but there is a trigger. It is powerful with just one rubber band - 15 to 20 ft max range, 10 ft effective range. By effective range I mean the max distance where the round is still moving on a straight path without an arc. This the first gun that I can take full credit for.

Step 1: Gather Parts

the parts you will need are

RODS:
2 red
3 yellow (required but they will be the ammo)
1 blue
2 white
3 green

CONNECTORS:
12 yellow
1 orange
3 grey angles

EXTRAS:
5 black clips
6 blue spacers

Step 2: Build Trigger

This is a simple step. The picture should explain fully.

Step 3: Build Barrel

This is the longest step. The main body of the gun is also the barrel. The series of pictures should explain fully again.

Step 4: Add Rubber Band Handles

Add pegs for the rubber band and attach the rubber band

Step 5: Add Front Handle

The handle is made of three yellow rods.

Step 6: Loading and Firing

This is a bit complicated and may seem very much like an 1800s style gun, but you'll get the hang of it. First you push a yellow rod into the barrel. The you use the blue rod on the trigger to push it out of the back of the gun. Grab the yellow rod and reattach the blue rod to the trigger. Pull the yellow rod back and make sure the trigger locks. Pull the blue rod on the trigger to fire. The pictures may give more detail.

Step 7: Finished!

I hope you have some fun with this. I haven't yet tried a sharpened point on the ammo. I think it may be more liable to misfire. Leave a comment if you try; I'd love to see how it turns out. Also, try to see how powerful this thing can get. I just got some new rubber bands today, so I'll be trying too.