Knex Concept Gun: Bullpup Bolt Action Repeating Slingshot


Introduction: Knex Concept Gun: Bullpup Bolt Action Repeating Slingshot

About: Knex builder here at Instructables. I build Guns, and, Roller Coaster. I currently build about 2-3 guns a month. I strive to post quality as well as quantity. If you have any ideas for a gun for me to try ou...

Hello instructables! My third collaboration with blue mullet, and it's a big achievement! A bullpup bolt action, repeating sling shot. This gun was inspired by the cross bolt nerf gun. Many people over the years have been trying to make a repeating sling shot, the biggest mistake people made when building was putting the mag in front of the trigger. With this design, the slide pulls back the rubber band on to a trigger that is angled below the main barrel. Then a arm pulls the bullet out of the mag, over the trigger, and onto the barrel. Never before has someone made a repeating slingshot, that uses one single motion.

I could have never done it without blue mullet. He was not able to finish his because of his ball machine hornets nest. We brain stormed for hours on this mighty task. Long tedious hours of building with plastic, and shooting cats with nerf guns hehe (sorry I had to say it blue)

Hopefully this concept will be tackled by other users and Mabey one day take over pin guns.

It's a repeating sling shot!
Bolt Action
70 foot range
Shoots metallic clips and purple connectors
Very nice trigger
Decent looks
Jams very little
Bolt come out the back of the gun :(

Hopefully this sparks some innovation back in the community. I will have a vid up soon and blue mullet should have one after his ball machine is complete.

Again special thanks to Blue Mullet!
~Lucas The Boss~



    • Stick It! Contest

      Stick It! Contest
    • Backpack Challenge

      Backpack Challenge
    • Game Life Contest

      Game Life Contest

    31 Discussions

    Finally, my zipdart has been eclipsed :P

    Great job dude, that looks awesome!

    I've gotta get back into things again, so many new innovations since I stepped out--I might be able to use a couple to figure out how to get my pullpup idea working :)

    Nice gun, like the look of it, I have a gun, hopefully posting it soonish, just got to finish it off. It is a remake of my NYG The other little project at the end of my bal concept post. I just haven't been posting anything new recently!

    2 replies

    It may be a while, but I've said to myself that I will post it!

    Excellent, now have it fire finned ammo, perhaps use a pump. Then you're well on your way to making a very war-worthy weapon. Also, for as small of ammo you're using, I think you could get away with not needing to have a bolt that goes out the back of the gun. The mechanism I imagined was an internal part that was pulled over the magazine with a rubber band. Then you'd use the slingshot band to push back this part, uncovering the magazine and letting a bullet out, and then sliding the bullet forward out of the mag until the band catches on the trigger. This could be done via a bolt or pump I imagine. Should improve reliability by removing complexity and isolating the mechanism inside the chamber. I'm sure other repeating slingshots have used something like this before.

    Glad to see you're still building.

    4 replies

    I think there need to be a lot more advancement on this concept before it's ready for a war. Making it shoot would be extremely difficult to do and would require a long and uncomfortable stock. We wanted to keep it compact so the bolt was necessary for it to function. I would love to see you try this concept and see what you can turn out. I'm pretty sure this has never been done. I know the kinetic rifle was a slingshot with a mag but it required two actions to prime the gun. Thank you though! I've been building a lot recently.

    I don't see how giving it the bolt made it more compact. I was trying to save you space with the idea I presented. And what's your definition of a single action? I mean technically with a bolt, you have to pull it back and push it forward, two distinct actions, just in a smoother package. But that is better than two separate, unrelated actions. What are you working on next?
    Oh I'd love to give it a shot when I get more pieces. Perhaps I'll try to make a proof of concept for a magazine and barrel design. I don't know if I can make a gun yet though.

    Well what I meant by single action is you are accomplishing two things without having to take your hand off the slide. A few years ago my dad tore out his rotator cuff and had to do physical therapy, he had this massive surgical tubing stuff and gave it to me. I'm going to try and make a sling shot that uses it (not repeating). That stuff is like an inch think so I should get some serious range.

    I hate to say this but I can't believe that you got a blue clip or a grey clip to go 70 ft. Our velocity shot yellow rods only about 60 ft

    1 reply

    Slingshots naturally have more power than a rail gun. Metallic clips are small and roundish having less surface area for the air to slow down.

    What changes did you make? I'll have the vid up soon.