Knex Pump Action Gun




About: Very oldschool Knex gun builder. I invented everything. Now I just go to wars.

Ok here's a little gun i made out of knex. It's small and is good for making a few to play with friends. Also, it shoots pretty far and is easy to reload :)

Step 1: The Hopper and Shooting Platform

the gray connectors and blue rings are where the green "bullets" are kept. and the little black connector between the red rod and red connector is so the bullets don't fall through when you reload

Step 2: Locking Thing

this is to lock the firing piston after you pull back the pump

Step 3: Pump and Firing Piston


Step 4: Locking Thing + "launching Pad"

connect the end of the red rod on the locker to the yellow connector on the launchpad. then the orange connector to the side of the write connector

Step 5: + Pump and Piston

slide the pump on so it points tward the front, then the piston in over it
make sure the free-moving red connector on the locker is to the right of the rod on the piston

Step 6: Handle and Trigger

put a handle on. and a trigger by sliding a grey connecton onto the stub of the leftover red rod. then use another red rod to connect the grey and free-moving red connector. get 2 medium sized rubber bands, one thick and one thin.

Step 7: Rubber Bands

use the thin rubber band to pull the pump back into the starting position, and the think one to fire the piston.

and then you're all done! just fill the top with about 5 small green rods. put your thumb on the back of the first red rod (next to the trigger) and pull back on the pump and let go of it. then push the trigger down with your thumb and it shoots :D



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    100 Discussions


    2 months ago

    this was the first gun i made out of knex 3 years ago


    9 years ago on Introduction

    i made a mod so that the hopper could be larger u need 1 blue rod 2 orange connectors 2 blue spacers 3 dark grey connectors hook an orange connector on the blue rod. put 2 grey connectors a blue spacer grey connector blue spacer and then a orange connector. second pic is how to attatch dont care if its not a mod, trying to make a hopper to sit on top

    download.jpgdownload (1).jpg
    1 reply

    Reply 9 years ago on Introduction

    I did something like that a very long time ago when I made a machine gun that used this hopper. Instead, I used light gray connectors instead of dark gray on the top of the hopper, then I attached a gray rod to them.


    9 years ago on Step 7

    Doesn't work well at all but I like the idea and design. It's kooll


    10 years ago on Step 7

    the design is great but it isn't very reliable. The mach just doesnt work when you pull the pump.


    12 years ago

    whoa! i shot mine 18 1/2 feet! that's farther than any gun i've built... that's sad because iv'e made the AST rifle, and it shot 6 feet...

    4 replies

    Reply 12 years ago

    You could probably increase the range of the AST rifle by changing the magazine to use smaller rounds. Also did you figure out the trigger and use a broccoli band?


    Reply 11 years ago on Introduction

    yo, i made the ast and its good, except the firing pin sometimes blew up the magazine :)

    An Villainjli1

    Reply 10 years ago on Introduction

    sometimes? it exploded the mag EVERY shot, so i modded the magazine. it worked good but didn't fire far so i broke it.