Yet Another K'nex Gun (YAKG)

Let's face it. There are a lot of K'nex guns on Instructables. After looking a most of them, I wasn't satisfied with any single one. Some had good ideas, such as a good handle, firing pin, or trigger, but none had it all. So, I decided to make my own gun, pulling together various parts from other guns. Never fear, everyone who's ideas I used get credit in the next step.

  • This is my first Instructable, and is subject to spelling errors, typos, incorrect part count, etc. Please let me know if you find any problems!

Step 1: Information

  • Repeat capability: Re-cock*
  • Ammo type: Blue rod
  • Ammo storage: Bottom-loading magazine
  • Ammo capacity: 15 blue rods
  • Trigger type: True trigger (front-blocking type)
  • Rubber band capacity: up to 8

Extra features:
  • Simple adjustable laser mount (mod)
  • Recoil dampening (mod)

And in case you missed it, that's magazine, not hopper. You can fire this upside-down.

Where I got the ideas from:

Anybody can build a K'nex gun, but it takes something else to come up with ideas. I am a big advocate for people getting credit for their ideas, so I will show where all of the ideas for this gun came from.

Firing Pin:
Rubber Band Sliders:
  • This isn't my idea, I got it from a gun with big wheels sticking out of the sides. I can't find it anymore. Let me know if you see it.

Breech (modified connectors):
*Most people incorrectly call this semi-auto.

Step 2: Parts

Here is what you'll need:

  • 23x White
  • 20x Yellow
  • 14x Red
  • 11x Light Gray
  • 6x Orange
  • 1x Modified Orange
  • 21x Dark Gray
  • 3x Modified Dark Gray
Total Connectors: 99

  • 2x Gray
  • 1x Black (or Gray)
  • 5x Red
  • 11x Yellow
  • 6x Blue
  • 23x White
  • 25x Green
Total Rods: 73

  • 8x Tan Hubcap
  • 58x Blue Donut
  • 2+x Large Thick Rubber Band
  • 2x Small Thin Rubber Band
Other parts: 66

Total Parts: 238

No exotic parts!

Don't let the part count scare you. Most of it is green rods and blue donuts. This is actually a very simple gun to build.

Optional: (for mods)
  • 4x Tan Hubcaps
  • 3x Small thin rubber band
  • Laser Pointer
  • Masking tape
  • 2x Blue Donut
  • Small Strong Compression Spring

  • Dremel tool with cutoff disc or hacksaw

Step 3: "Enhanced" Parts

You will need to decapitate 3 gray connectors. If you've built many other K'nex guns, you should already have some. If not,

1. Clamp down the connector with the hole sticking out.
2. Using a dremel or a hacksaw, cut off the top half (or a little more) of the hole.
3. Smooth it out with the dremel or sandpaper or your fingers.
You will need 3 of these.

I believe the modified orange connector is a new part. It's very simple.

1. Clamp down the connector with one end sticking out.
2. Dremel, hacksaw, bite off, whatever, one jaw of one end.
You only need one.

Important note:
The modified orange is optional unless you are using many rubber bands. If you do not feel like modifying one right now, you may proceed building. Be warned, however, that the unmodified orange connector makes it a lot easier for the gun to accidentally go off. The effect is magnified with more rubber bands. Never use more than 3 rubber bands with an unmodified connector, as the results will be unpredictable.

Step 4: Handle

Although simple in concept, this piece is hard on the hands. There's no good way to do it.

1: You'll need to stick 18 white snowflake connectors onto 4 red rods. Play around with it until they all go on.
2: Stick one red rod loose in the middle.

Step 5: Trigger

1: Simple enough, right?
2: Make that piece shown above. Use the modified orange connector from step 3.
3: Stick the piece you just made in the hole.
4: Add donuts and the light gray connector.
5: Cap it off, add another blue rod, and a green rod.
6: Add 3 dark gray pieces and another donut.

Step 6: Barrel

View is upside-down until picture 4.

1: Build this. Not nearly as hard as the handle.
2: Add the trigger like this
3: And the handle too. Make sure all 3 red rods slide in properly.
4: Build the part on the left, and double check the part on the right.
5: Add it.

Step 7: Magazine

1: Make these. Note that one of them has blue donuts.
2: Insert 8 yellow rods. The ends are highlighted in pink.
3: Connect your two pieces together like this.
4: Now, flip this assembly upside-down and connect it to the barrel. Note that the side with the blue donuts is closer to the handle.

Set this aside.

5: Make these.
6: Connect them together with blue rods and donuts.
7: Add more blue donuts and tan hubcaps.
8: Finally, flip the gun upside-down. With any luck, the piece you just made should slide right into place, and lock in with the light gray connectors.

Step 8: Breech

1: Make this. Use a half-gray.
2: Add two more half-grays.
3: Turn that piece upside down and insert it into the gun.
4: Make sure these white rods align properly.
5: Add 9 gray connectors on each of the yellow rods.

Step 9: Firing Pin and Pusher

Firing Pin
1: Build this.
2: Insert it into the back of the barrel. You may need to press the trigger to let it go all the way forward.

3: Build this.
4: Turn the gun upside-down and slide it into the magazine.

Step 10: Adding Rubber Bands

1: Loop a rubber band around the front of the trigger as shown.
2: Remove the two white rods, and loop a rubber band over the front like this.
3: Stretch it along the length of the gun, across the blue donuts.
4: Attach it to the firing pin as shown.
5: Add more rubber bands. Alternate above/below the orange connector.
6: Replace the white rods.
7: Remember those two red connectors you were saving? Here is where they go.

Step 11: Loading and Firing

1: Turn the gun upside-down and remove the pusher.
2: Add up to 15 rods into the magazine. This takes practice.
  • For the first 7 or 8 rods, you may want to insert them through the hole shown in the picture.
  • It may be necessary during loading to jam the pusher into the magazine to settle the rods.
3: Replace the pusher, and strap it in with a rubber band.

4: Hold the gun from the front with your non-dominant hand.
5: Pull back the red connectors on the firing pin until the trigger locks into place.
6: You may want to ensure that the firing pin is correctly locked in.
7: Hold the gun by the handle with one hand and pull the trigger.

Important note about loading:
Do not load with the firing pin pulled back. Not only is this stupid, unnecessary, and unsafe, it just plain won't work. The extra tension on the rubber bands from the firing pin pulled back causes the magazine to compress slightly, preventing the rods from sliding down correctly.

Step 12: Option #1: Laser Mount

These options are just that. Optional. You should have a fully functional YAKG by now. If you wish, you may stop reading this instructable.

Yeah right, like that's ever gonna happen. You want to make your YAKG better, right? Right.

This one is very simple. Mount pretty much any laser pointer onto this gun.

1: Get yourself a laser pointer. Put a rubber band around it, so that you don't have to manually hold the power button.
2: Add 4 tan hubcaps to the top of your gun.
3: Attach the laser pointer with 2 rubber bands.

You can slide the 4 tan hubcaps to adjust the laser.

Step 13: Option #2: Reinforced Firing Pin

If you are using a lot of rubber bands, you will notice that the back end of the firing pin may break off sometimes. Here is how you can reinforce it.

1: Remove all rubber bands, and take out the firing pin.
2: Remove the red connectors from the black rod.
3: Wrap a small piece (3-4 in, 7-10 cm) of masking tape around the end of the firing pin to give it a little extra thickness.
4: Replace the red connectors, re-insert the firing pin, and replace rubber bands.
  • If it's easy to snap on the red connectors, add more masking tape.
  • It helps to snap on one red connector at a time.

Step 14: Option #3: Recoil Dampening

You may notice this gun tends to kick forward a little when the firing pin hits the barrel. This can throw off your laser and/or your aim. Here is how to minimize that recoil.

Go to your hardware store. Bring a small K'nex rod with you. Find a nice strong compression spring that fits closely around the K'nex rod. Clamp down your spring, and cut it to about 3/4" with your dremel or hacksaw. If you use a dremel, it makes cool fireworks-like sparks.

1: This is about what your spring should look like.
3: Remove the rubber bands and take out the firing pin.
4: Place your spring onto the black rod, with a blue donut on either side.
5: Stick the firing pin back in, and replace the rubber bands.

Step 15: Wrapup / Troubleshooting

I hope you have enjoyed building the YAKG. Have fun and be safe. Don't torment your pets or siblings with this.

With enough rubber bands, it can penetrate paper easily with blunt rods. Sharpened rods are even more dangerous.

Troubleshooting / Maintenance
  • Be sure to check the area around the breech for loose rods, especially if you didn't do Option #3: Recoil Dampening.
  • It is fairly safe to fire a few times without any ammo, but repeated "firing on empty" could damage the red connector on the pusher, and break the magazine.
  • If the rods come about halfway out of the barrel and stop, they are getting caught on the other rods. You must be using very weak rubber bands. Get some stronger ones.
  • If the firing pin flies off, your rubber bands are too strong. Consider weaker rubber bands, or search Instructables for a stronger firing pin. You can also add more tape on Option #2: Reinforced Firing Pin
  • If your rubber bands wear quickly, make sure they are on the blue rollers, under the first white rod, and threaded onto the firing pin correctly. Refer to step 10 for rubber band loading information.

Happy shooting!



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    84 Discussions


    7 years ago on Step 15

    This is one of the few K'nex guns I have made off of this awesome web site, and by far this one is the BEST!!!! Thanks for posting all of the instructions clearly!!!! Some guns i see only show a picture of a gun with no instructions, and i am not very good at following that!!!!
    Thanks again, please post more!!!


    8 years ago on Step 3

    Or you can just use a ball joint socket for the "decapitated" grey connector coudn't you?

    You can get recoil on a knex gun because recoil is the backwards shock. Remember every action has an euqal and opposite re-action


    Reply 10 years ago on Introduction

    Yes but it's so overpowered by the ram pushing forward, it's virtually undetectable.


    Reply 10 years ago on Introduction

    Oh sorry. "u are a nerd" -> "No he isn't. it's common knowlede basically"