Introduction: Knex Catapult-Gun Hybrid

Picture of Knex Catapult-Gun Hybrid

This is a knex gun that uses a firing mechanism that is similar to a catapult. It is pretty small, can fire any length rod, and has a true trigger. The actual power comes from pulling the trigger, not from a rubber band, so the distance it shoots depends on how hard you pull the trigger. This also makes it so don't need to cock it back each time you shoot.

Any comments or constructive criticism (even negative) are appreciated. And please rate it if you like it. Thanks.

Step 1: Body and Handle

Picture of Body and Handle

Just follow the pictures... Not too complicated.

Step 2: Top Part

Picture of Top Part

This is the part attatched to the trigger that pulls the catapult arm. The last three pictures show how it is attatched to the body.

Step 3: The Arm

Picture of The Arm

This is the part that flings the ammo rods into the air. A little more complicated, but you should be able to get it through the pictures.

Pics 1-3: Show the whole arm from different angles
Pics 4-5: Show two different parts of the arm
Pic 6: Shows how to put the two pieces of the arm together
Pics 7-10: Show how to attach it to the body

Step 4: Rubber Band and Operation

Picture of Rubber Band and Operation

Put the rubber band that keeps the arm back in the following spots. To fire, just stick any size rod in the orange connectors' hole on the arm and then pull the trigger. I've found that blue rods work best as ammo.


didexo (author)2014-07-03

Better than the TR for sure!

jayboy2431 (author)2012-02-10

not the best range 1-5 ft if you made the barrel longer or a way to make the trigger pull faster it would fire better

thehoyboy (author)2010-12-08

good gun

CODKING (author)2010-06-23

do u wnt me to make all of the picturs or no

CODKING (author)2010-06-23

do u wnt me to make all of the picturs or no

knex_mepalm (author)2009-07-10

Does this work without the band in response to my question?

smickel (author)knex_mepalm2009-07-22

Yes, it works without the rubber band, however it won't automatically return to the "cocked" position.

smattman22 (author)smickel2010-02-11

add a hopper or something and you've got semi-auto :D

knex_mepalm (author)smickel2009-07-24


An Villain (author)2009-08-14

interesting design, very innovative, 5*. could use a better handle though (fixed.)

knex gun maker (author)2009-04-14 join this club copy and paste to the url box , we would like to see your knex guns and advertise the url on knex instructables

ben-with-his-knex (author)2009-04-06

really cool catapult-gun

lou33mig41 (author)2009-03-31

how powerfull is it?

Undermig (author)2008-12-28

erm does it shoot ure self?

smickel (author)Undermig2008-12-28

No it doesn't. You're probably holding it backwards.

Undermig (author)smickel2009-01-02

lol ok

Wafflicious (author)2008-11-28

i did something like this earlier this year. I used dsman's crossbow's ratchet system so it used rubber band power.

shmi117 (author)2008-11-06

I am currently making a mag for this gun... ill post when i can and if it works out.

bounty1012 (author)2008-07-25

it is pretty cool i was making it to destroy a lego castle but it didnt but it is a very good gun. nice idea

Oompa-Loompa (author)2008-07-16

This could get some imagination flowing. good gun.

Storm950 (author)2008-05-07

The design is nice and seems to work, but in reality this goes no more than 6 feet.

smickel (author)Storm9502008-05-07

To be honest, I didn't design it for power, I was looking for a new way to fire things. So consider this a prototype. I may tweak the design to add more power, or do something like dsman suggested and use rubber band power for my next design. Thanks to all of you who like it, I'm glad you do.

StyleCore (author)2008-05-05

I Like It and i would know, hence the name

carrothead23 (author)2008-05-05

this is the coolest thing on instructables!!!!!!!!!!
=) =P

its so freakin fun!!!!!!!!!!!!!!!!!!!!!

23GUITAR05 (author)2008-05-04

I am am obsessed with catapults this is AWESOME!

bobbyk881 (author)2008-05-04

This looks like a smaller version of my catapult, But better. This thing is awsome!! Great job.

I_am_Canadian (author)2008-05-04

nice! I might suggest putting it on a frame that is a blue length across instead of a white. That way you can have a sturdier frame and handle. good job, though.

daz108 (author)2008-05-04

this could be the new thing and it could be made semi auto

dsman195276 (author)2008-05-04

well, its not bad, but not powerful.maybe if you make is so the trigger holds the arm back, instead of pushing it forward, you could hook rubber bands to the arm to get more power.

s0lekill3r (author)2008-05-04

Hmm...if you add a mag to this somehow, it would be semi-auto... This is a pretty ingenious firing system, like a handheld catapult +1 from me.

thebboy (author)2008-05-04 +.........................1....................................... wow

Danny A (author)2008-05-04

New............... Wierd............. ....................................And I Like It...........................................

lodefreak (author)2008-05-04

wtf? this is so weird! but good +1!

agent harmsy (author)2008-05-04

Crazy! i like it!

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