Introduction: K'NEX Repeater RBG

Picture of K'NEX Repeater RBG
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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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

Picture of 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.)

Picture of 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!

Picture of 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!

Picture of 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.


mdperry977 (author)2014-10-11

I couldn't get the trigger system to work

screenguy (author)2010-05-29

 i modded thid gun so it shoots farther and pretty neat systen i built the barrel by looking at the pics and i got it right

KnexFreek (author)2009-12-19

 does it shoot one at a time or all at once?

123bob321 (author)2009-11-19

i want the barrel instructions badly. (lol i tried 2 make it by picture)

danroy99 (author)2009-05-28

where could I find instructions for the rest of this gun

cj81499 (author)danroy992009-09-03

you dont need them just look at it i is easy if you think. i did it so it cant bee that hard

cj81499 (author)cj814992009-09-03

ps the instructions leave out some major info but i can give you some pics of the mech i did for this it is a little different but not by alot

cj81499 (author)cj814992009-09-03

pps and pics of the barrel

revtiedye (author)danroy992009-09-02

If you have a good supply of Knex, you may want to check out my adaptation of this gun. It does have full instructions, even though the last few pictures are blurry. I've had good comments--and a few criticisms. But it does take a ton of green connectors; I was trying to make it sturdy.

cj81499 (author)2009-09-03

never mind i figured out how to make it and i added the knex awsome stock it is soo cool!!!!

link too it below

kizman (author)2008-01-24

hey nice gun, think you could add the barrel to the instructable, would help me alot as i am a beginner to this k'nex gun stuff.

revtiedye (author)kizman2008-05-14

I was very pleased with what I developed from the repeater mechanism here. If you want to see my rugged rubber band shooter, check it out:

Gunzo The Great

revtiedye (author)revtiedye2009-09-02

By the way MrRadicalEd, I've gotten tons of compliments on my implementation of your repeater mechanism. I've done my best to let folks know I got the geometry from you. But I thought you might want to know that it's been over a year, and I'm still getting comments. Thanks again.

MrRadicalEd (author)kizman2008-06-09

revtiedye, that is a very logical revision to the design. Nice work

Kizman(and everyone else wondering), I have plans for the barrel and much more in the works here at Instructables. I have decreased the size of my RBG and made improvements for a more solid and fun platform. It will come fairly soon.

hobobob (author)2009-08-24

my picture has a hobo with a sign saying children captured by ninjas need $4 karate lesseons

hobobob (author)2009-08-24

i need some k'nex gun instructables to get me started out and i need some ideas for making one

samsara55 (author)2009-06-17

its nice

MrRadicalEd (author)2008-06-18

An update this instructable is in the works do to my acquisition of some new toys. All of my future Knex instructables will be in this new media.

Storm950 (author)MrRadicalEd2008-06-20

Umm, what do you have planned for your future Knex?

MrRadicalEd (author)Storm9502008-06-20

I have two gun models, some automotive parts I am considering, and some misc models for fun.

chinese_boy (author)MrRadicalEd2009-06-06

whats aking so long for you to update this article

DJ Radio (author)MrRadicalEd2008-07-25

that makes the ible worse....

danroy99 (author)2009-05-26

could you please hurry up with the rest of the instructions I'm excited for the instructions for the barrel and quick stock

therandomperson (author)2009-04-05

Is there a mag on that gun?

no its a Rbg

well naa i can see stupid just some people can put the 2 togethrer....

therandomperson (author)2009-04-05

The pictures aren't perfect...

brammeke11 (author)2009-02-05

This is not that good but is mod able. i made an 8 round 3-shot shotgun out of this, with comfi handle.

FutJJ (author)2009-01-10

i made a sniper with this system, just watch it, also made a p90, but taked the p90 apart

ghost19855 (author)2008-12-29

you are soooooooooooo stupid you changed every picture and this gun doesnt even work!!!!!!!!!!!!!!!!

Wafflicious (author)ghost198552008-12-29

it does if you add green rods to the trigger inside the gun

DJ Radio (author)2008-08-06

Can I use your trigger mechanism on my new gun. I wasn't gonna ask, but you haven't given the instructions for the stock and barrel

adamsdead (author)2007-12-07

Why did you do the same thing as bedbugg? Its retarded!!!! Why is everyone creating new accounts == JUST == so the can have a better rating?!!!

DJ Radio (author)adamsdead2008-08-05

dude, this guy beat bedbugg by 7 months!

Knexagon (author)adamsdead2007-12-17

He made this instruction first?

adamsdead (author)Knexagon2007-12-17


DJ Radio (author)2008-08-05

this is good, I've added a new stock and bipod, but I do have a complaint this is full auto and is only semi-auto if you have fast fingers (that happened once, the semi-auto) I really liked the safety, it's a nice touch for when you are playing a knex sniper game and you are assaulted from behind and the gun is stolen. the guy will try to use it, but can't pull the trigger. neat prank....

hornbadoing (author)2008-07-29

make a youtube vid on how to make it kk

brammeke11 (author)2008-07-04

may I have your parts list on sketchup or maybe you can export them too the sketchup library

brammeke11 (author)2008-07-04

nice system, I modded it a little bit and my gun shoots now 24 rubber bands in pairs of 3. do you guys make this pictures with skechtup? man your guys are good... I can´t even build my own house on sketchup

codemaster2590 (author)2008-06-19

how did you get the skech up design. Could you tell the website or just how you installed it.

I used Imperar's knex pieces in SketchUp to model what I had made. It is ridiculously easy; especially if you have ever mapped for a game like HL or Quake.

snake_eyes (author)2008-06-13


knexarethebest (author)2008-06-10

hat looks preaty neat but bedbugg2 already used the trigger design.

Check the instructables dates to see who's was posted earlier.

well sssoooorrrryyyyyyy!

Kerwination (author)2008-03-28

how do i prevent all the rubberbands from flying off when i pull the trigger??

revtiedye (author)Kerwination2008-05-12

If it is built properly it should hold several rubber bands. In my experience, when you add too many rubber bands, the first time you fire it, the wheel spins with so much force it overwhelms the repeater catch. Try it with 2 rubber bands, and if it works right, try again with 3, then 4, etc. If it doesn't work with 2, you either built it wrong, or your barrel is too long.

revtiedye (author)2008-05-10

I wish I saw your gun before I spent 2 weeks trying to design my own. But the design process was pretty fun. I like yours a lot better. I'm going to have to redesign the handle, because my son can't get his hand around this one. I support you in the way you gave very thorough instructions on the trigger mechanism, and left the barrel up to us. I'm sick of complete yet vague instructables. I've gotten halfway through a few guns and gave up because the instructions know...lame.

DRADIS (author)2008-04-24

Best RBG I've built +1

About This Instructable




Bio: I am obsessed with design...
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