Introduction: Knetix Semi Auto Knex Gun

Picture of Knetix Semi Auto Knex Gun

This knex gun is different from other semi auto guns because instead of using manual power to pull back the pin, the tension of wound rubber bands is used, making the trigger easier to pull and very unlikely to break when you pull it.

I give credit to extreme builder for the pullback mechanism (the black wheel)

I also give credit to revtiedye for the trigger and placement of the band wheel

Semi automatic
Very sturdy
Shoots farther than most semi auto guns (about 15 feet)

Needs to be wound every few shots
Does not shoot as far as a pull-back gun would


Step 1: Frames and Main Supports

Picture of Frames and Main Supports

The body frames and mandatory supports of the gun. This step also includes the safety lock

Step 2: Firing Chamber and Magazine

Picture of Firing Chamber and Magazine

The firing chamber is my original design. The magazine feeds straight into it so it there's no little crevice for rods to get jammed in. This also includes the mag ram.

Step 3: Sight

Picture of Sight

The sight of the gun-sight also functions as the band guide

Step 4: The Guts

Picture of The Guts

These are the innards of the gun. This includes the pullback mechanism, the band wheel, the trigger, etc.

Step 5: The Butt :)

Picture of The Butt :)

The butt... a really easy step

Step 6: The Firing Pin

Picture of The Firing Pin

This is the firing pin that extreme builder used-i modified the tip a little to decrease friction.

Step 7: The Chain

Picture of The Chain

This is the big chain that you see on the side of the gun. If you find out a way to replace the chain with gears without getting in the way of the other parts please tell me-the chain causes a lot of friction that makes it harder to pull back the pin.

Step 8: Attaching the Guts

Picture of Attaching the Guts

This tells you where to put all the innards. This does not include the outer gears

Step 9: Attaching the Gears and Chain Gears

Picture of Attaching the Gears and Chain Gears

The outer gears and chain gears of the gun.

Step 10: Adding the Rubber Bands

Picture of Adding the Rubber Bands

This is where the rubber bands go

Step 11: Optional Supports

Picture of Optional Supports

The optional supports. I would use them but you dont have to

Step 12: Winding, Loading, and Firing

Picture of Winding, Loading, and Firing

You are done!!! It would be best to use a piece of surgical tubing as the wheel bands because it is stronger and thicker, so it is less likely to get jammed.


LvNo1000 (author)2013-08-09

Why isn't "requires a bunch of broken pieces" in the cons list? It would have been nice to know that before I got nearly half-way through making it and realized I wasn't willing to break that many pieces to make this.

TheRacker (author)2011-08-27

Kind of obsolete now, isnt it?

Football viking boy (author)2011-05-07

only shoots 15 feet????? there are a lot better semi auto guns

Hmmm...this gun is three years old maybe? And yeah there are but they're pseudos. If you want to see an amazing semi auto check out my forum semi auto. Not sure when it will get posted though because it still needs work.

Crumble (author)2010-11-22

is there an easy way to break the grey connector in step 1 pic 9?

slippdiddy (author)2010-11-04

AMAZING!!! i love it..... im building one but it has a second ram rod (or fireing pin) that smashes in to the firing pin to pull it back after you shoot, then on your second shot you pull the same trigger but it uses a different mech.... and there you have a semi auto..... but it only shoots two times then you have to cock it (so its not true) :( but i still like it and im getting close (im just on the concept) ....... awesome gun

slippdiddy (author)slippdiddy2010-11-05

here it is --->> still not realy working :(

glugnar (author)2010-09-07

looks awesome

Michaelgoode (author)2010-05-14

Is there a video of the gun shooting?

An Villain (author)2010-03-10

my rating boosted it over 4*

Madrias357 (author)2010-01-16

I have a method to rid yourself of the chain.  Use the little sized k'nex wheels, and a rubber band.

Kinetic (author)Madrias3572010-01-16

 Maybe-it might not grip well enough though. Good idea however.

Senior Waffleman (author)2009-12-20

you seem to use the same stock and handle in ur guns

KnexFreek (author)2009-11-26

it looks really cool :) !!!

Kinetic (author)KnexFreek2009-11-28


devon34 (author)2009-10-29

its good but your handle is a bit rubish

Kinetic (author)devon342009-10-29

What makes you say that?  Works perfectly for me.  And if you have a problem with it you can easily mod it to fit your wants. 

devon34 (author)Kinetic2009-11-01

i havent made it but it looks a little bit fimsy

Kinetic (author)devon342009-11-01

It actually works fine, since it is 5 layers thick. 

devon34 (author)Kinetic2009-11-01

is it powerfull and what does the chain do

Kinetic (author)devon342009-11-01

The chain connects the band wheel (where the energy is) to the firing pin.  It gets about 10-15 feet.   

GeekBeam (author)2009-10-24

how many and what pieces do you need

Kinetic (author)GeekBeam2009-10-25

Sorry man this gun was taken apart a long time ago.  I have no idea.   

Knetix (author)2009-04-25

hey ppl sry i havent been answerin any questions-i lost my old account (kinetic) so i see that there is a lot of controversy about this gun. Yerjoking-i lookd @ ur profile and i dont c any semi autos at all so dont be trying to compare us-and also-oodas semi auto inst really a gun-more like a handheld cannon-guns use triggers, not levers-of course u can get more power uf ur usin ur whole arm instead of just ur fingr-no offense 2 ooda- its still a great design

GeekBeam (author)Knetix2009-10-24

oh no need to worry it happens from time to time, sucks when you have a good account going ,and *poof* it's gone

Kinetic (author)GeekBeam2009-10-25

Actually I just couldn't remember the password but I figured it out afte a while thank god lol 

DrWeird117 (author)2009-03-22

Damn it! This is cool, and new. Why so many complaints?

DJ Radio (author)DrWeird1172009-03-26

because ppl think its not TSA

DrWeird117 (author)DJ Radio2009-03-29

They should actually build it.

GeekBeam (author)DrWeird1172009-10-24

duh they need to build it before they critique it im going to do so later on

Fred the Penguin (author)2009-04-15

my revolver is probably one of the closest guns to semi auto it uses a sharpened ball connecter to hit the white rod in the bullet holder of a rotary drum, it uses a hammer to help this and all 8 shots can be pulled in under 5 seconds heres pic:


ooh aah cool looking gun man

Knetix (author)Fred the Penguin2009-05-05

u should post it--i would build it

GeekBeam (author)Knetix2009-10-24

me too

It's not the closest to a semi auto, we have semi auto's already, lol. Never seen a fully working semi auto revolver yet, only seen certain parts.

DJ Radio (author)yerjoking2009-08-29

Combine BRv1 turret with Ednator 55's semi auto mech.

Kinetic (author)DJ Radio2009-10-09

 Thats actually a really good I'm going to try that some time.

yerjoking (author)DJ Radio2009-09-02

Then you have a gun which will shoot even worse than the original gun.

DJ Radio (author)yerjoking2009-09-02

Yeah, but semi autos are not power guns, but concept guns.

yerjoking (author)DJ Radio2009-09-03

But you want a gun that can shoot atleast 10 feet with semi auto.

agent harmsy (author)2009-08-29

OH COME ON! I built the entire gun, up to adding the gears, only to find I CANT FINISH IT BECAUSE I ONLY HAVE ONE GOLD GEAR! Epic failed.

GeekBeam (author)agent harmsy2009-10-24

hey dont you have a grey gear that doesnt attach with tan locks like the other gears(its one of the earliest gear types knex made)

Kinetic (author)agent harmsy2009-08-30

thats horrible-it might work with just one but if might break

agriff (author)2009-06-16

what is the chain made of?

chazman2 (author)agriff2009-09-26

der its knex

caebersbach (author)agriff2009-06-22

Plastic K'nex chain pieces

squarepants (author)2009-08-31

the handle looks kinda unfinished with the white rods stickin out

Kinetic (author)squarepants2009-08-31

na i do that on purpose-i just like it that way you can build it however you want though

squarepants (author)Kinetic2009-09-01

thats a nice idea-built it to suit you.

About This Instructable




Bio: Sometimes it takes a man to push beyond what he thinks is possible before he realizes that possibility is a mere conception of the mind ... More »
More by Kinetic:The Kinno-2: A Semi-Automatic K'nex GunThe Kinno-1: K'nex Semi Automatic Rifle (preview)The Kinetic Sling Pistol (KIC2 contest entry)
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