Introduction: Echo Crossbow

Picture of Echo Crossbow

That's right, a repeating crossbow.

Step 1: Barrel

Picture of Barrel

1 - Rails. Make two

2 - Barrel walls. Make two

3 - Barrel floor

4 - Add the floor parts to one of the walls with white rods as shown

5 - Add the other wall

6 - Add the rails onto the sides of the barrel

7 - Closeup of the back, showing how to secure the rails

Step 2: Trigger

Picture of Trigger

1 - Make

2 - Make

3 - Make

4 - Put them all together

5 - Add to barrel. Shown without the rails for clarity

Step 3: Handle

Picture of Handle

1 - Make

2 - Put the pieces together with three white rods

3 - Attach to the barrel. Shown without rails

Step 4: Magazine

Picture of Magazine

Or just the top of the crossbow in general

1 - Oops, sorta blurry. Walls of the magazine

2 - Sides of the magazine

3 - Attach four white rods at appropriate places on one wall

4 - Slide side walls onto previously mentioned white rods

5 - Attach the other wall

6 - This goes on the back for a little stability

7 - Attach the magazine to the barrel

Step 5: Bow

Picture of Bow

What's a crossbow without a bow?

1 - Two stiff, gray-sized rods in the front of the barrel. Connect at the ends with light grays

2 - Add two red connectors and two white rods to each side like so

Step 6: Pump

Picture of Pump

1 - Make

2 - Make

3 - Add two yellow connectors to what you made from pic 2

4 - Connect the two things together

5 - Add the white rods and yellow connectors to the ends

6 - Prongs - they hold the rubber band. Make two

7 - How the pump attaches to the barrel. It takes a little pushing and pulling to get it around the rails

8 - Attaching the prongs to the pump. The white rods just slip into the hole of the middle yellow connector

Step 7: Finishing

Picture of Finishing

1 - Three bolts is all it can hold

2 - Pusher

3 - Two #64 bands tied together function as the bowstring

4 - Attach the tied bands around the front white connectors

5 - Rubber band for the trigger. Hook it in the orange connector and then around the white rod. This makes it not get stuck when you pull it down

6 - Bands for the pusher

7 - How the bolts should look inside the barrel.

When the tied bands are pulled back, they should go over the angled edge of the trigger and hook on the back. With those bands out of the way, a bolt gets pushed down into the barrel (note - sometimes the magazine and the barrel aren't exactly aligned. If this happens, just push the side of the mag a little so they line up). After firing, the system will reset. Just repeat.

Happy shooting and comments/criticism always welcome!


ninjalim (author)2014-07-30

thanks i realy like it

bboy321321 (author)2012-12-15

how powerful is it, I'm guess i know in about an hour

KnexFreek (author)2010-02-01

 Hey dradis, have you seen my repeating crossbow?

crestind (author)2008-11-15

Interesting! Sort of like the Chinese Zhu Ge Nu.

wangtrevor (author)crestind2009-12-29

lol i call this the nu plain nu

Stavroz (author)crestind2009-01-01

You mean the Chu Ko Nu.

crestind (author)Stavroz2009-08-19

Well in pinyin it's zhu ge nu.

SnapFitPieces(: (author)2009-12-12

 Seriously dude put in a ratchet it will be a killer

beameron (author)2009-05-04

This works for ANYONE AT ALL ?? How to fire and load and lock and stuff IT DOESNT WORK !!

it dosent work but mine will

beameron (author)2009-05-04

NO WAY !!! U can lock this device U just made fack sh*t :P +_=

Bugman9 (author)2009-03-13

I made it and added a stalk with a scope and a big rubberband from the doctors.

ILIKEPIE333 (author)2009-01-31


Stavroz (author)2009-01-02

I have it suscribed faved and fived. XD (Sorry Viccie ure lines)

Stavroz (author)2009-01-02

It would be awesome to make te bow a sort of folding out like this on 0:13.

to make it more portable.

Skreetsha (author)2009-01-02

Sweet idea, man! fived and faved!

Stavroz (author)2009-01-01

Cool idea, so its pump action or is it like a bold?

Electroinnovation (author)2008-12-16

You totally have a great idea!!!! Now for me to mod. I promise in under 1 month I will come out with a repeating crossbow that has a range of over 50 feet and will hold 5 shots. It wont have a pump but it will be insane.

DrWeird117 (author)2008-12-10

HALP! Everytime I try to pump it, the band doesn't go around the trigger...

DRADIS (author)DrWeird1172008-12-11

Sometimes you may need to pull the trigger down slightly in order to give it a little extra help, OR you put a green rod into the middle of the bottom of the pump, facing the trigger, so it bumps into the trigger and pushes it down slightly.

DrWeird117 (author)DRADIS2008-12-14


Nazgul (author)2008-11-22
DrWeird117 (author)2008-11-14

By repeating, do you mean semi-auto?

DRADIS (author)DrWeird1172008-11-15

No, just rapid fire

DrWeird117 (author)DRADIS2008-11-16


Dutchj (author)2008-11-09

Awesome. I tried my hand at making a repeating crossbow twice, but the first failed, and the second one blew up all the time. I guess I should have just used rubber bands on the second one though, flexible limbs are impossible with K'nex T_T

Wicky (author)Dutchj2008-11-11

Nope not impossible, I did make one, that had 2 hinges near the center of the bow and had loads of rubber bands there.
Wasn't very powerful though =|

Dutchj (author)Wicky2008-11-11

It would be possible that way, and it would have some good power because of leverage if applied correctly. But technically it would still be powered by rubber bands, not by the limbs.

Wicky (author)Dutchj2008-11-11

Well it only simulates it =d

But building one that uses pieces actually bending sounds very hard to pull off; if not impossible =o

iKill (author)Wicky2008-11-11

mepains crossbow uses flexi arms....

Dutchj (author)iKill2008-11-11

I've never really tested how well that performed, even though I did build it. I guess I couldn't get it to work.

iKill (author)Dutchj2008-11-12

it was amazing!!!!!!

Vynash (author)2008-11-12


s0lekill3r (author)2008-11-09

I was just working on a repeating crossbow but miserably failed, glad to see someone succeed! Nice job =D.

plasmaspy (author)s0lekill3r2008-11-09

same i tried but failed too

Oblivitus (author)2008-11-09

I just finished making this, impressive mech, but it is low power and capacity.

Oompa-Loompa (author)2008-11-09

this is the peak of all knex crossbow inventions. You have my respect, sir DRADIS.

Storm950 (author)2008-11-09


jollex (author)2008-11-09

THIS IS AWESOME! I will build once I destroy my new sniper that is using all my yellows.

grevious (author)2008-11-09

looks pretty freaking tanked.
needs a better handle and a stock then it would be one of the best looking xbow on the site =D

pls (author)2008-11-08

ooooo neat!

About This Instructable




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