Picture of 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
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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

Picture of 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

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

dude this thing rocks just built but the only down side is that is does not shoot good for me
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....
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.
Sypran6 years ago
cool, I'm gona build this and put a seige on the playground fort hahaha
good idea
im gonna terrorisate the mcdonald's playground=D
sounds fun.... can i join in?
That's gonna be fun!!
Let's both build one and shoot children?
i would but im 3 years too late :3
do u have to use the flexi-rods for the barrel
skyfaller4 years ago
This is good!

You should check out I_Am_canadian's knex heavy cannon.
Brad G4 years ago
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 ;)
instruct394 years ago
you need cannon ammo not little tiny ammo u cant find after shooting it, other than that very cool! 5*
clader15 years ago
dude it doesn't go 60-70 feet. you lier i shot it it went 150-200 feet !!!!
lol XD its really cool!
Furloy5 years ago
 4.5 stars, it skeletonish
I gotta say it looks good. 4.5*
i think that it is really cool but i do agree that it could use more reinforcement. I think that it would be cool if you made it a breech loading cannon if you made any mods to it.
knexkrazy (author)  codemaster25906 years ago
Thanks! I'm working on a second version that has more parts, but it takes a lot of pieces.
Umm? "second version that has more parts, but it takes a lot of pieces." LOL
so how far can this canon shot 70 80 feet or is it a low range gunthat can only shot about 20 feet
lol it say right there /\ /\ /\ /\ /\
Skreetsha6 years ago
Cool! A bit skeletony but, it probably functions as it looks, and that would be great :D 5 stars!
Oh yeah... Nice wheels Nice pictures.
alfpwns6 years ago
builder9686 years ago
pretty cool. I know i dont have any howework tomorrow evening;might build.
then again, i might not. might build on sunday(saturday i have a friend's party).
arrow shot6 years ago
nice, but i hardly believe that cannon barrel is life sized...maybe provide us with a picture? of the real thing>?
knexkrazy (author)  arrow shot6 years ago
This is the cannon I was modeling it after. Of course I can't go true life size without using a TON of parts. But, I called it life size because it is VERY big and looks pretty much like the real thing.
Yeah, it actually is almost life sized...If i had to guess, i would say 5/8? Havent built this yet though, so idk...too many peices for me XD
apples!!!!!6 years ago
Now I don't know if I want to work on the one I wanted to....
yerjoking6 years ago
Wow, I'd just love to sit at the back then fire it at someones face, they'd get owned lol.
Master_Zane6 years ago
Sweet! Looks Great!
knexkrazy (author)  Master_Zane6 years ago
uguy6 years ago
Life size?
knexkrazy (author)  uguy6 years ago
I said in my intro that it was "almost" life size. Actually, it isn't too much smaller than some cannons, but obviously not "real" life size.
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