Hello, this is a little slingshot that I've made. It has gone through many names, such being bow and cannon, but I've come up with the most suitable word for it: a slingshot. It can fire from my house's kitchen, through the dining room and slightly into the living room with a medium band.

How it Works:
1: Pull the rubber band that is attached to the front onto the 2 white rods sticking out in the back of the slingshot.
2: Rip off one of the slingshot's legs :D (the red connector with a yellow rod on it's middle slot.
3: quickly pull the leg so that the red connector goes between the 2 white rods in the back, pull it up and let go. PEW! you send the leg across the room.

This is an ideal 'shot for fun and mostly non-lethal K'nex wars with friends! It might sting at point blank or the sort, though.
This slingshot it totally built for single-shot, but, if you have enough dexterity, don't forget the multi-shot feature as in all slingshots.

Step 1: List of Pieces Required

These are the required pieces for a whole Lobster cannon. NOT INCLUDING AMMO which takes another 4 red connectors, and 4 yellow rods (1 yellow plugged into the middle slot of each red conector)

LIST OF PIECES FOR THE ITEM:
-Connectors-
2 Whites/Snowflakes
2 Small Greys
2 Light Browns/Pins
4 Reds
4 Blacks/"Y"s
5 Greens
9 Yellows
11 Purples

-Rods-
2 Yellows
2 Stretchy Oranges
2 Stretchy Light BluishPurples (can be replaced by blue)
3 Blues
9 Whites
10 Deep Greens

-Misc-
1 Rubber band (I use a medium-thick band but the others might work as well)

EDIT: you should be able to do normal purples instead of the stretchy ones; I just use the stretchy ones for comfort.

Step 2: Number 1-10 Steps

The pictures should be sufficient; Comment for misc problems and I will try to answer them.

Step 3: Number 11-21 (final) Steps

Follow pics, again, and feel free to comment/ask for help

Step 4: Firing

If you're seeing this, you probably completed the gun, good job! :)
When the rubber band is in place, take an ammo off the Stretchy Oranges, pull it back and out of between the two whites in the back, and fire!