This is my first Instructable and it utilizies a new firing system quite unlike all other knex guns on this site. It uses a "catapult" system where a rubber band is pulled back and over a bullet in the barrel and is catapulted forward by the rubber band. It is hard to understand from writing, but make this gun (or something like it) and find out how awesome it is! (I got this gun to shoot 60+ feet, and this new firing system is more efficient per rubberband, so the bullets fly faster as well)

Step 1: Construct Stock

Pretty self explanatory,just make this picture. This is optional, it just makes the gun look cooler.

Step 2: Construct Piece Which Holds Rubberband at the Front of the Gun and Gets Pulled Back on to the Bullet Which Eventually Will Be Fired

Well, the name of this step pretty much says it all.
1. Completed Piece
2.First Thing You do
3.Add green connectors, blue circle things, and something at the ends (doesn't have to be the beige things)
4. Add long rubber band to the top tooth of the green connector, and secure it on both green connectors by putting on green rods over the rubber band.

Step 3: Construct Barrel and Front of Gun

Sorry for not too many pictures on this step.However, it is self-explanatory.
1. Construct this large piece. Line up two long grey rods and connect them with 7 yellow connectors. Then put on 8 greys on either side before putting another yellow connector to secure that. Add two more greys on each side, another yellow connector, 10 grets on one side, another yellow connector, and then add two orange connectors to what is left of the original two grey rods. Finally, add three grey rods to the bottom of the yellow connectors as shown in the picture. (sorry for this being confusing)
2. Add handle by putting 7 yellow rods to the bottom of the Yellow Connectors
3. Construct Trigger
4. The final piece, with trigger inserted into barrel. Insert trigger by putting the blue end into the yellow barrel at the end of the gun and attatching the other end of the trigger on to it. This makes it so the trigger won't fall out of the gun.

Step 4: Construct End of Gun's Body

Sorry for only one picture, but it's easy to follow. Just make what is in the picture.

Step 5: Put Things Together

1. This is where you connect the two ends of the body. The Three orange/black connectors shown here are connected.
2. Other part where the two ends are connected. snap the grey rods onto the yellow/grey connector, and attatch the rods to the orange connector.
3. Attatch the stock to the end of gun as shown here.
4. Attatch the piece that holds the rubber band to the front of the gun, as shown here.

Step 6: Loading/Firing

1. This is the ammo you want to use, the ones on the left work the best.
2. Put ammo into the end of barrel as shown here
3. Pull rubber band back and around the ammo, as shown here.
4. Another image of loaded gun. Pull back on the trigger, and the piece will get catapulted forward very quickly and it will fire very far.
5. Here are some other guns I have made using this system. They include single, double, and triple shot guns, and I have a five shot as well.
6. Just a sicknasty picture of the loaded gun and aiming.