Introduction: The Logic Bow

Picture of The Logic Bow

This gun reached 6th highest rating for knex!!!

Whether you like it or not, here it is.

Because I cannot be bothered typing out a wall of text here is some stuff from my forum topic.

The concept behind The Logic Bow
By using a ratchet system to hold the bands behind the pin you can:
@ Decrease pin friction in barrel
@ Increase pullback distance
@ Increase power
@ Make the pin easier to pullback
@ Have a simple rail system

This is a pin type gun, not a slingshot. It uses a ratchet system to hold the rubber bands, therefore increasing the amount of bands that can be used and increasing ease of pullback. These bands are released when the trigger is pulled, propelling the pin into the bullet. This means that the effective pullback distance is increased, therefore increasing the range and power.

well here is the first "new thing" I have done in ages, (the last Truly innovative thing I built was the D-Frag grenade) the Logic Bow. It uses an all new 4-stage firing system that runs between two rails (I tried using a dual rail system but that didn't work out). So far I have the mech working, but it needs the rest of the body, the bow, a handle and probably a stock. It is a single shot that should have more power than a pin gun, the really cool thing about it is that although it uses a pin mech the pin takes almost no effort to slide back.

Review by Knex Gun Builder

and how I would rate it.
power 8/10 incredible power for a pin gun
rate of fire 2/10 for single shot version
rate of fire 5/10 for the turreted version, very slow
range 7/10 one of the highest ranged pin guns out there
comfort 7/10 comfy but could be better
innovation 9/10 first gun of its type, but not exactly new (lt licorice)
ease of use 10/10 my sister can use it, nuff said
looks 6/10 not the best looking gun, but fully loaded from the front like in the pics it looks cool
War Rating: I would recomend it for large scale wars because:
-It has a better range than most guns
-It is quite large
-Low rate of fire is really bad in close quaters
overall 8/10 or 4* but rate it whatever you want.

Step 1: Front End

Picture of Front End

Sorry its all in one chunk, I couldn't be bothered taking it apart, it should be easy enough to build though.

Step 2: Handle and Trigger

Picture of Handle and Trigger

Again I couldn't be bothered to break this up completely, but you should manage.

Step 3: The Middle Rail.

Picture of The Middle Rail.

I did this one properly, you do not need the orange connectors on the z axis, they just add more support.

Step 4: Assembly and Loading

Picture of Assembly and Loading

wow, that was fast

Loading and firing
1 pull back bands onto ratchet, make sure they are at the back.
2 pull back pin
3 stick bullet into front barrel, make sure it is locked into the bullet lock
4 point the gun at whatever you want to die*
5 pull trigger and watch what ever you pointed it at get pwned

*so don't point it at anyone, seriously don't.

Step 5: Questions and Other Stuff.

Picture of Questions and Other Stuff.

if you have any questions ask them here, also if you do build it post a pic

Step 6: Turreted Version

Picture of Turreted Version

Well here's how to turn your Logic Bow into the turreted version. This shows how to mod it into an 8 shot turret but you can just as easily use an 18 shot version by using a black rod on the bottom connector slot.

Step 7: Ultra Logic Bow

Picture of Ultra Logic Bow

Bigger, Meaner, Awsomer.

Well after a long string of failed projects I rebuilt the L Bow. But this time I made many improvements to the original design, these include:
-Removing the bottom of the rail to get rid of friction
-Modifying the handle for comfort
-Adding a removable stock
-A more intergrated turret design (the old one looks like it was just stuck on)
-A tactical rail for things like ammo holders or a bipod
-A support rail to add strength.

Although there are pictures on my OB, there are more here


shieldsam (author)2011-12-23

i added a stock and a scope but i destroyed it before i could get any pictures

destorny (author)2011-12-19

please repost the insturctions

destorny (author)2011-12-18

please repost the first two parts of the logic bow i can't get the lower part that is like a hand rail for comfort ......... to confusing :(

beanieostrich (author)2011-06-08

Hey logic boy, may I build this gun and give you credit?

DracoUltima (author)2011-05-22

I have built it, and it was not-so-good, the first is it takes a LONG time to reload. The second is that this mechanism ADDS friction. I have put on 7 bands thinking that it will go super far, but it didn't, 50 feet was what I got at best, with a sniper rod. Maybe, it's just me, or maybe it's just the gun, I'm not sure. I built it correctly, everything is identical. If you could, please post a video of it shooting 100+ feet.
I mean the range is still better than a lot of other knex guns but not as high as you claim. For now, 3.5*.

Hmm strange, tbh I never had any of those problems. as for the video, I am disinclined to build this gun again, I'd rather rebuild the newer version of it (picture below)

some possible solutions:
Pin/body not completely straight. this means that the pin has more friction than it should and would possibly cause reduced range, to fix replace pin/recheck body

Version: the singled version definitely shot further than the turreted version. Also remove the orange connectors under the pin, I found that they added alot of friction. (see step 7 for full list of mods)

Bands: use new #64 bands for best results and attach them one at a time, this makes sure that they fit together properly.

travw (author)2009-11-22

So what's the range with 7 bands, and sniper rods?

Fred the Penguin (author)travw2009-11-22

I think like 40 metres or something maybe even 50. I can get 30m flat with 5 bands and a sniper rod. Also don't bother with oodammo for this gun, they flip, can you believe it? oodammo defeated!

what??? it can't be!

travw (author)Fred the Penguin2009-11-23

50 meters? Woez. I can't believe Oodammo doesn't work with this! Did you push it all the way in? Did you make the Oodammo correctly? /sarcasm

TheFoofinator (author)travw2010-06-13

Oodammo is ment to be shot flat, because the wieght of the two sides of the red connectors make it accurate, in this becasue the grey connectors are close to each other on the turret, you have to put the oodammo in on a slant, so they aren't flat

Fred the Penguin (author)travw2009-11-23

the oodammo just spins wildly out of control and falls to the ground, sniper rods don't do that.

travw (author)Fred the Penguin2009-11-23

How far does it go before it bites the dust?
*"Another one rides the bus.........Another one rides the bus........."*

Fred the Penguin (author)travw2009-11-23


travw (author)Fred the Penguin2009-11-23

Estimate? 10 meters? 20,000,000 meters?

Fred the Penguin (author)travw2009-11-23

sorry for the unsatisfactory reply, I had to go cook dinner, we had meatballs!
when testing guns inside our house I use my firing range, it is 10m long with a target at one end. I aim at the centre of the target (a4 page) and fire 10 rounds, from this I can judge a guns performance.
Using oodammo with 4 64's on Logic Bow I hit the target 1/10 times, with sniper rods I got 10/10.

I think it would fire oodammo maybe, 15-20 meters with a bit of luck?

travw (author)Fred the Penguin2009-11-24

Ok, no problem.
Wow. I wonder why it doesn't work for you?
How do regular rods work? Like reds or yellows?

Fred the Penguin (author)travw2009-11-24

worse than oodammo, 15 meters if I'm lucky, best ammo for this after sniper rods are red rods with a red connector tip.

travw (author)Fred the Penguin2009-11-24


Fred the Penguin (author)travw2009-11-24

I got time.

 can you add stock

i did, but don't bother with that old version, the as yet unreleased version kicks its @$$ in every way.

travw (author)Fred the Penguin2009-11-25


Fred the Penguin (author)travw2009-11-24

If I get time I may stick a turret on this just for the hell of it.

smart person (author)2010-08-04


182515 (author)2010-06-23

Where does the pin guide attach to the back?

travw (author)2009-11-23

"...they aren't necessary..."

muffinslayer2 (author)travw2010-04-15

Nobody cares about grammar mistakes, just go away and stop correcting people...

heatblast (author)muffinslayer22010-04-18

 WHAT?  You can't be serious........................... >_>

heatblast (author)2010-04-01

The rating is 4.02* now :). I think the haters left the building, just like Elvis Presley.XD. I would'nt be so sure though, sometimes they come back to haunt you a second time. :(

ol987986 (author)heatblast2010-04-05

ha i improved it so now your wrong

heatblast (author)ol9879862010-04-13

Wow, you sure are a sight for sore eyes LOL jk XD.

I don't really care for ratings

Good for you!:) You don't have to care, they're just DUMB ol ratings anyway. :p

Pizzapie500 (author)2010-02-11

Aww, you didn't post this...

it should be easy enough to make from the pics especially number 11.

Vynash (author)2010-02-07

This gun is great!

I love it 5*ed and favorited!

knexsuperbuilderfreak (author)2010-02-07

 great gun i have some pics for step 2 if you want them just tell me and ill up load them

 made a parts list

red:6(2 tan)
flex1 orange:1

dark gray:22
lt gray:2

blue spacers:20
tan clip:3


Dirtyboyy (author)2010-02-05

are you dutch ?

nope, I am from New Zealand

barrax (author)2010-02-02

lol just looked at the third picture

i see one of mine at number 7 :)

Fred the Penguin (author)barrax2010-02-02

yeah but that was before this got rated down into oblivion

~Z~ (author)2010-01-24

I only got like 15 ft with 3 bands....

Fred the Penguin (author)~Z~2010-01-24

-what sized bands were you using?
-did you make sure that the pat that holds the ammo lined up with the barrel?
-try removing the top set of orange connectors.

~Z~ (author)Fred the Penguin2010-01-24

OH well.. its too late i took it apart (Ouch)

lol10 (author)2010-01-09

One of the best turret/revolver guns I have seen. I'd say it's up there with the TR series, Knexsayer, and the D-TAB.

Fred the Penguin (author)lol102010-01-24


squarepants (author)2009-12-29

5*-best gun of 2009? one of them definitely!

About This Instructable




Bio: The majority of stuff posted here (instructables) is rubbish and as I now have better things to do I will be less active. also as ... More »
More by Fred the Penguin:Gen 2. HAWC BowMy new(ish) pistolIllogic Bow
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