Introduction: K'NEX Repeater RBG

About: I am obsessed with design...
Back in mid November of '07 I was itching to try out at making a rubber band gun out of K'NEX, but I was disappointed with the performance of the designed guns that I came across. So after some tinkering I came up with a design of my own. This firing mechanism is simple and performs great with a variety of rubber band ammunition.

  • Notice
  • Please observe caution when using this rubber band gun mechanism. Parts will fly off if loading rubber bands improperly. Please use sense to match the rubber band size to the mechanism you are building, and please play safely.

This is a semi-automatic rubber band gun with 8 pegs. This design includes a safety for the trigger, and an easy loading system.

6.19.08: These instructions are being updated to feature the barrel and quick stock seen in this design. Check back soon for these updates.

Step 1: Receiver: Making the Side Pieces

The receiver contains the wheel, spacers and trigger sandwiched together. Create two of these side pieces.

Step 2: Receiver: Adding Rods

The two sides are initially held together by three blue rods. From there we add connectors for support.

1. Add the first rod on the yellow connector towards the bottom.

2. Add the next rod on the same yellow connector, but on the other side.

3. The third rod goes on the white connector's inner connector.

Step 3: Receiver: Adding Rear Spacers

With the rods in place, we can add three yellow connectors that act as spacers.

1. On the lowest rod, insert a yellow rod. Three yellow connectors will be placed next to each other.

2. A second connector goes next to the first.

3. The third connector is placed in the same way making the back of this handle more rigid.

Step 4: Receiver: Adding Front Spacers

Just like the last step, we are adding more connectors that act as spacers. These spacers not only offer stability, but keep the trigger locked in a resting position to be pulled.

1. A green connector goes on one side of the blue rod.

2. The red connector goes next to the first green connector you added.

3. The second green connector goes next to the red connector.

Step 5: Receiver: Adding Safety Pieces

These next two connectors are used to lock the trigger in place. This is a nice feature for such a creation; however, this step is option.

1. A green connector goes on one side of the rod.

2. The Gray connector goes on the other side of the same blue rod.

In the end, each piece should be touching a side piece of the handle. Later, when you want to lock the trigger, slide the green connector to the center to prevent the trigger from being pulled. The gray connector acts as a stop.

Step 6: Receiver: Creating the Trigger, Trigger's Pin, and Spacer

Now to add the actual trigger and spacers. These spacer make sure the trigger moves smoothly.

Step 7: Receiver: Adding the Trigger, Trigger's Pin, and Spacers

1. Start by hold the pin you made in one hand, but leave one side of the pin (blue spacer piece and connector) off to slide it through the white connector. As your sliding the pin in, insert one of the spacers as seen in the picture. The pin will partially hold the spacer you made in place.

2. Just as you did in Step 1, insert the trigger while pushing the pin through.

3. Next, add the second spacer while you push the pin through to the other side.

4. Replace the gray connector and blue spacer piece to the end of the pin to close it off.

Step 8: Reciever: Making and Adding the Spacer Pin

Just as before, you will need to make another pin to hold up those spacers you've just added. This pin goes through the top holes securing the spacers in place.

Step 9: Trigger Frame - Making and Adding the Toothed Wheel

Now for that one vital piece, the toothed wheel. This is where all the rubber bands will be loaded on to. Like previous steps, this involves creating a pin to hold this wheel in place.

Use the small blue spacer pieces to make sure the wheel is in the very center of this pin.

Again, this step is like steps 7 and 8.

Step 10: Making the Trigger Work

All that is left is to add a small rubber band to the trigger to make the whole thing operate properly.

First. Try and find a rubber band slightly larger than a quarter as seen in the picture.

Step 11: Adding the Rubber Band

With the rubber band, loop it around so that it is attatched to both ends of the blue peg under the trigger.

Step 12: Adding the Rubber Band (cont.)

Lastly, you must take one side of the looped rubber band and bring it up to a part of the trigger within the frame.

As you can see. The rubber band must be attatched to the small green peg on the trigger itself inside the frame. This makes the trigger snap back.

Step 13: Trigger Mechanism Completed!

As Of: 6.19.08
These Instructables are being updated to feature instructions for creating the featured barrel and quick stock used for this rubber band gun. Check back soon for updates.

Step 14: RELOAD!

It is important to match the rubber bands to the length of barrel you make to insure smooth operation.

I recommend rubber bands that are slightly wide(not the rope "thin" kind)

Second Picture: Stretch the rubber band from the barrel tip to the first firing peg. The firing peg is not exactly 90 degrees, but facing only slightly toward the front of the gun.

Note: After loading one rubber band on the firing peg, cock the wheel backward to expose a new peg in the same position. Load the rubber bands in this backwards fashion untill all pegs are full.

See the attatched video to watch in action!

Step 15: FIRE!

Firing is as simple as pulling the trigger! I hope everyone enjoys this design, and always always ALWAYS be careful and excercise caution when using rubber band guns.