Life Size K'nex War Cannon

Introduction: Life Size K'nex War Cannon

Here it is the best of the best life size (or almost life size) war cannon. Yes I know there are lots of knex cannons on Instructables but this one is different from the rest. It looks like a cannon. It will shoot 60 - 70 feet with 2 rubber bands ,and will shoot though 4 pieces of paper. This does use ALOT of parts so I took the time to take a part count so you don't waste your time. It uses a more simple trigger Then IAC cannon but it(kinda) uses the same mech.

looks great
wonderful distance 60 - 70 feel with 2 rubber bands
will completely destroy 3 pieces of paper

uses a lot of pieces

Step 1: Part Count


76 gray

70 red

37 yellow

27 blue

55 white

100 green


17 white

40 blue

44 yellow

58 purple

70 green

27 red

6 gray

11 orange


4 gray clips

8 small gears

I can't give a number of spacers. Because the number will differ for each person.

18 black hands

2 rubber bands

Step 2: Wheels

Okay you might recognize these wheels they are from IAC's cannon but I enlarged them by 5 times.

Step 1: build 2

Step 2: add rods to one of them

Step 3: Build 8

Step 4: connect both sides

Step 5: add rods with spacers to all of the spaces

Okay now do this whole section again.

Step 3: Barrel

Okay I tried to do this as good as I could but it was very difficult for me to make this part of the Instructable.

PIC 1-2: build this part (it is the front of the barrel) PC 2 is of the same part upside down

PIC 3-4: build this. It is the middle part of the barrel.

PIC 5-6: build . This is the back part of the barrel and the firing mech

If you can't follow any of this Instructable let me know on my orange board and I'll try to help.

Step 4: Connecting the Barrel

Okay now we are going to connect the three parts of the barrel we just made.

Pic 1: connect the 3rd part with the 2nd

Pic 2: now connect the front with the rest.

Pic 3: you are done with the barrel it should look like this. ignore the bow thing we will make that in a bit

onto the next step. >>>>>>>>>

Step 5: Body

Okay this is more easy.

Step 1: build 2

Step 2: build this little thing ( both rods need to be black)

Step 3: connect the last 2 parts we made together

Step 4: connect both sides with the red rods

Step 5: build

Step 6: add last part

Step 7: add gray rods

Step 8: add gray rods

Yay half way done!! onto the next step >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Step 6: Stand

okay. We are to the stand.

Step 1: build

Step 2: build

Step 3: connect both sides

Step 7: Connect the Parts

It is time to connect all the parts.

Pic 1: connect body and stand

Pic 2: add 3 spacers on each side.

Pic 3: add wheel and put however many spacers needed to fill the rod (will be different on each side)

Pic 4-5: now we are going to connect the barrel to the body.

Pic 6: Build

Pic 7: tie 2 rubber band together

Pic 8: add "bow" and rubber bands

Pic 9: build

Pic 10: build

Step 8: Loading & Firing

This is very easy

Pic 1: Load it like this.

Pic 2: pull rubber bands back and hook onto the ammo.

when you are ready to fire just pull out the pin.

You are done!!!!!!!!

Have a lot of fun!!

If you have any questions let me know.

Let me know what you think.

1 Person Made This Project!


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9 years ago on Introduction

This was the first of the cannons that i built about four and a half years ago on this site.

bob the HUNTER

dude this thing rocks just built but the only down side is that is does not shoot good for me

Dr MonkeyMan
Dr MonkeyMan

Reply 9 years ago on Introduction

I built 4 of this but i didnt bulled the wheels so i took the cannon pieces and attached the barrels to my arm and walked to into the libreary with it....

Dr MonkeyMan
Dr MonkeyMan

9 years ago on Introduction

I built this and i tested out how far the projectile would fly so i put it in our drive way and pulled the trigger and the piece flew out and hit a moving car. The person stopped so i pulled the cannon behind are car and waited for him to leave.


14 years ago on Introduction

cool, I'm gona build this and put a seige on the playground fort hahaha


Reply 12 years ago on Introduction

sounds fun.... can i join in?


Reply 9 years ago on Introduction

i would but im 3 years too late :3


12 years ago on Introduction

This is good!

You should check out I_Am_canadian's knex heavy cannon.

Brad G
Brad G

12 years ago on Introduction

Modded this quite a bit, ALOT less skeletal it looks pretty awesome ;) fully metallic shoots a bigger projectile (like IAC Cannons) and the end of the barrel is modded a little, i will try and get pictures thanks for making this great cannon ;)


12 years ago on Introduction

you need cannon ammo not little tiny ammo u cant find after shooting it, other than that very cool! 5*


12 years ago on Introduction

dude it doesn't go 60-70 feet. you lier i shot it it went 150-200 feet !!!!