Introduction: (True)Semi-automatic Knex Pistol.

Picture of (True)Semi-automatic Knex Pistol.

I as tinkering around and made a semi-auto one.

Oh and.. I know it's weak, because I made it mostly for scientific design, not for performance. So feel free to take it farther and make a real shooter out of it. : )

Step 1: Hopper and Front

Picture of Hopper and Front

this is the hopper and front of the gun. like the last one, the gray connectors and blue spacers are the hopper ;and the black piece under it is there to stop bullets from falling through.

Step 2: Firing Thing

Picture of Firing Thing

the yellow rod is what hits the bullets to make them go flying; and the chunk on the right is the handle. that red connector with the green rod on it is the trigger.

Step 3: Important Piece

Picture of Important Piece

this is connected to the trigger and pulls the firing piston back.
(sorry the picture is blury)

Step 4: Another Important Piece

Picture of Another Important Piece

this makes the piston release as you pull back the trigger

Step 5: Hopper + Firing Thing

Picture of Hopper + Firing Thing

connect the black rod and the orange connector to: the yellow connector and the white rod on the hopper piece respectively.

Step 6: + Trigger Piece

Picture of + Trigger Piece

this is a lil hard, put the red rod into the grey pieces sticking out of the shooting thing. then lift it up a little and attatch it to the trigger. then put a small black piece between the trigger and grey pieces for stability.

Step 7: Rubber Bands

Picture of Rubber Bands

put a thick rubber band on the firing piston and a thin one on the trigger.

Step 8: + Thing

Picture of + Thing

put that thing on the blue rod comming off the hopper (this view is from the top of the gun)


ok now you're done!
load 7 small green rods into the hopper and hold somwere on the back (front too if you want accuracy and a more confortable position) and pull the trigger until it shoots. make 2 and use one in each hand ;-)

sorry for the sloppy instructions and any misspellings "-_-


Knex4Life23 (author)2012-07-27

Sorry for my lack of knowlegde but what is a Patch.

JesusChrist101 (author)2011-09-07

its ok...

sneature (author)2011-07-02

i cant tell what that one piece is connected to the upper tan piece does anyone know what it is

Jedi_man (author)sneature2011-08-12

If you are talking about the gray one, it's a 2 way connector. If you are talking about the white one, it's a white rod.

lhinkle (author)2011-01-28

really awsome gun but how to fire it

oodalumps (author)lhinkle2011-01-28

Pull the rod connector back like a trigger.

X Files (author)oodalumps2011-07-18

i find that the thing that pulls back the ram needs to be pulled left like a block trigger. i've made the mod that makes the gun true, and i'll post it soon.

oodalumps (author)X Files2011-07-18

If you really want to use this gun, here is the v2. It's a lot better.

oodalumps (author)X Files2011-07-18

Then you built it wrong. The white rod that sticks up on the front of the trigger mech hits that piece from step 4, releasing the pin.

X Files (author)2011-07-18

actually upon building it, i've found that the ammo falls out of the bottom of the magazine. i would appreciate it if you could fix that.

oodalumps (author)X Files2011-07-18

Sounds like you didn't put in the black Y connector. Step 1, the only part I put a box over.

But this gun is seriously old (the 6th knex gun ever posted on instructables). It isn't all that great. Just go build the WASP on if you want a semiauto.

X Files (author)2011-07-16

its a good gun, but the name isnt very accurate. truly semi automatic is where there is no ram that needs to be pulled or pumped or bolted. i have a mech i've been keeping to myself, and i think im gonna release it now. nice gun tho! :-)

X Files (author)X Files2011-07-16

o ok i see. but still plz check out min new instructable. i published it literaly 2 minutes ago!

oodalumps (author)X Files2011-07-16

This is a true semi auto. You never pull a ram back, you just pull the trigger.

ultimachris (author)2010-04-12

A mechanical masterpiece! Simplistic yet efficient, small but sturdy, it's just a brilliant piece of work! I'm putting this mech in a rifle I'm currently working on if you don't mind. I'll give credit to you if i post it.

oodalumps (author)ultimachris2010-04-12

I once put an up-scaled version of this mech into a rifle. You can use it for reference:

NotExactly (author)oodalumps2010-04-25

genius mech. do you happy to be KnexGunTutorials or Untd103? Because hes posting instructions of that rifle on his website.

DJ Radio (author)NotExactly2010-07-16

That's actually someone else, who stole ooda's design, and is posting without permission.

What a theif!
I go on that site, Destroying noobish guns makes me feel important.

jmand (author)2011-04-15

dude this really is a genius design a bit peicey though like with the 1 conecters
and every thing needs a tune up
but i im gonna try to incorporate this into my pistol im workin on
semi auto will make it that much better

Bartboy (author)2009-07-04

If this were posted today, it would be a fail. In many ways.... :(

oodalumps (author)Bartboy2009-07-04

You do realize this is a true semi-auto, don't you?

Bartboy (author)oodalumps2009-07-04

Yes, I know that. There are a few of them now, and they are better than this. This was fantastic at the time, but it shoots less that 20 feet, and is uncomfortable.

oodalumps (author)Bartboy2009-07-05

The other ones used a lot of pieces and don't shoot any farther.

Bartboy (author)oodalumps2009-07-05

They do use a lot of pieces, but they do shoot further. A lot further.

oodalumps (author)Bartboy2009-07-05

Are you talking about the pseudo semi-autos that use lots of preloaded rubberbands?

Bartboy (author)oodalumps2009-07-05

There are many variety's... And this isn't semi-auto. It's a repeater...... (I think)

oodalumps (author)Bartboy2009-07-05

My pistol is semi-auto.

Bartboy (author)oodalumps2009-07-05

This? It doesn't shoot very fast though....

oodalumps (author)Bartboy2009-07-05

It shoots every time you pull the trigger. What's not semi-auto about it?

Bartboy (author)oodalumps2009-07-05

Well it's semi auto, but isn't it a repeater?

oodalumps (author)Bartboy2009-07-05

What are you even trying to say?

Bartboy (author)oodalumps2009-07-05

Is this a repeater or semi auto?

oodalumps (author)Bartboy2009-07-06

It's a semi-auto. I think I've said that about a hundred times. Why even ask?

Bartboy (author)oodalumps2009-07-06

What is the difference? I am asking you 'cause you probably would be more helpful that google, but I guess not....

oodalumps (author)Bartboy2009-07-07

It's a gun that shoots every time you pull the trigger. You never need to pull back any pins or rubberbands to make it shoot, only the trigger.

Bartboy (author)oodalumps2009-07-07

And a repeater is...?

oodalumps (author)Bartboy2009-07-07

You pull back something then pull the trigger. Then repeat.

dragonsniper (author)oodalumps2011-03-05


knex_mepalm (author)oodalumps2009-08-19

i never knex you wrer on ibles...

oodalumps (author)knex_mepalm2009-08-20

you never knex i wrer on ibles...

knex_mepalm (author)oodalumps2009-08-20

sorry i meant i never knew you were on 'ibles, my hand is so used to typing knex that it comes up on everythinx

knex_mepalm (author)Bartboy2009-09-29

Why? Its a true semi-auto, you can't do that can you?

Bartboy (author)knex_mepalm2009-09-29

But the range and power is so bad....

knex_mepalm (author)Bartboy2009-09-30

It was made for scientific design not preformance, i bet if i tired i can make it stronger.

Bartboy (author)knex_mepalm2009-09-30

Not by much..... Pulling the trigger is pulling back the pin. If you can pull the pin back with one finger, it's too weak.

knex_mepalm (author)Bartboy2009-10-01

My new one is like a squezee gun you squeeze the trigger, shoots 25-30 feet

skyfaller (author)2011-02-26

It doesn't work for me, im sad. im pretty sure the trigger isnt pulling the ram back.

Abcwtfidontcare (author)2011-02-18

It's awesome, but is a bit skeleton like / very skinny.

It's one the oldest guns on this site. Build quality wasn't such an issue back then.

About This Instructable




Bio: Very oldschool Knex gun builder. I invented everything. Now I just go to wars.
More by oodalumps:7 Shot Knex PistolKnex Machine Gun(True)Semi-automatic Knex pistol.
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