I've made a lot of k'nex guns but none of mine can seem to beat this one. it can fit a small green rod, a white rod or up to three bb's. This is my first instructable so dont be too harsh.
You will need:
2 blue rods
2 orange connectors
1 grey 2-slot connector
5 grey 1-slot connectors
1 rubber band
Step 1: Make the Body/barrel...
Very simple, just make what you see in the picture...
Step 2: Now the Firing Pin...
Again, make what you see in the picture...
Step 3: Done!!
Put the firing pin through the top hles of the gun and put the two ends of the rubber band over the top parts of the orange thing.
pull back the pin, (be sure to move the trigger so that it holds) and put in some ammo!