Introduction: UKP .31 Caliber (Universal Knex Pistol)

Picture of UKP .31 Caliber (Universal Knex Pistol)

Here it is... what some of you might have been waiting for. 

Key Features:
-Under barrel laser (non functioning)
-Trigger guard
-5 round removable mag
-3 round removable quick clip with a reload time around 1.5 seconds, you read right, 1.5 seconds
-Iron sights
-Yes, it is a slightly different handle system than the TDS... don't say its the same, please.

-Small mag
-Accuracy is fairly low after 20 feet

-Amazing look (in my opinion)
-20-40 foot range depending on bands, not bad for a pistol
-Fast fire rate, you can fire the 5 round mag in about 6 seconds 
-Compact size 
*All of these factors make this pistol a superb choice for a secondary in any Knex war*

I know someone somewhere is saying "but my oodammo pistol has the same fire rate and a 13 round mag and better range" 

To that I say, "Then use it, but if you ever decide to look for a more tactical, realistic weapon to use as a secondary in a Knex war, then I suggest you come here first." 

I know my weapon will not compete with an oodammo pistol... so don't say that... what I was going for with this a tactical weapon with good looks that could be used in a Knex war, and thats what I achieved.

Without further ado, I present: The UKP .31 cal (yes I did the math right this time... don't look at the forum topic... just don't... it's fail math conversions)

Step 1: The Main Body

Picture of The Main Body

This is the main body of the gun... hence the title... 

Follow the yellow boxes, they will provide you with useless information at most times, but that one time you need help, the yellow boxes will help.

*READ the box on pic 5... If the gun doesn't feed right because you didn't read it, don't complain...*

Step 2: The Handle

Picture of The Handle

The barrel and handle are sort of merged together.. not 2 separate parts... so the build just continues building off the barrel... you'll see when you do it...

Please note the boxes If your a lefty, I built the gun being a righty... so the handle is formed for a righty. the boxes will tell you how to correct it for a lefty.

Step 3: Trigger

Picture of Trigger

Easy enough...

Step 4: Fake Barrel

Picture of Fake Barrel


Step 5: Fake Laser and Real Trigger Guard

Picture of Fake Laser and Real Trigger Guard

Well probably the most painful part of the build... and yes I forgot another picture... to finish the connection of the trigger guard just take the red 3 ways and slide them on the blue rod, really the only place it could go...

Step 6: Side Plates

Picture of Side Plates

Just to make the gun look better... build em' unless your way low on parts

Step 7: The Mag and Firing Pin

Picture of The Mag and Firing Pin

Last thing to build 

Step 8: Loading and Firing

Picture of Loading and Firing

I'll have a video of this and other stuff... but for now... 

The ammo is pictured below, and look its happy to see you! 

Take 3 rounds for a quick clip or 5 for a standard clip, pictures of each below

To load a standard mag, insert the magazine with the green rod prongs pointed towards the back of the handle and push up until it doesn't go any farther... It locks in place internally, you'll here a click when the mag is all the way in... next get a ram rod and shove it through the bottom of the mag and attach a rubber band.... then pull the ram back and shoot.

To load a quick clip (my favorite, fastest reload) pre assemble the quick clip assembly... insert the mag the same way as a 5 round mag... then pull the blue pin and the gun is then loaded and ready to fire! around 1.5 seconds 


Johnhall44 (author)2012-03-01

5* when are you going to post V2?

osi (author)Johnhall442013-07-21

osi (author)Johnhall442012-05-20

v3 is in the works. I played with v2 too much and got the slide messed up when I was trying to make it longer. V3 will outclass the both of these. hopefully

Johnhall44 (author)osi2012-05-21

ok =D

joejoe913 (author)2012-07-17

It is the Best pistol on the site! 5*

osi (author)joejoe9132013-07-21

osi (author)joejoe9132012-08-17

Thank you, means a lot.

SomeAsianKid (author)2012-08-27

Do we need the fake barrle?

osi (author)SomeAsianKid2013-07-21

osi (author)SomeAsianKid2012-11-09

not really

kwintisolo12234 (author)2012-09-22

hey man, i really like this, i think im going to build it but dont the bullets fall out of the mag easily?

osi (author)kwintisolo122342013-07-21

osi (author)kwintisolo122342012-11-09

not really... just stick a piece of tape over them when transporting. then pull it off before you load.

PotatoCoffee (author)2012-08-23

Looks cool. How is it universal?

osi (author)PotatoCoffee2013-07-21

osi (author)PotatoCoffee2012-11-09

USP- Universal Service Pistol. UKP- Universal Knex pistol. Just goes with the name.

XxsonicxX (author)2013-02-02

Best. Knex. Gun. EVAR!!!! 5 stars to you bro :) But how does the mag work. When I put the ammo in and then the mag rod, they fly everywhere! Plz help :(

XxsonicxX (author)XxsonicxX2013-02-02

Also You should work on the gun (The mag is 3 layers and the gun is 7 layers).

osi (author)XxsonicxX2013-07-21

osi (author)2010-12-21

Just throwing this out there... has anyone built this yet? if so what needs to be fixed? or clarified in the instructions? I know if there are build problems the gun WILL jam so... yea... post anything that goes wrong and I'll get on fixing it!

Andrew5909 (author)osi2012-02-07

the bullets jam in the mag alot tried fixing it, but i don't know how they jam

Fred the evil puppet (author)2011-06-05

probably the hardest step of the entire instructable... =D

osi (author)Fred the evil puppet2011-07-18

I mean, I tried everything I could to make it as easy as possible... but it just didn't come off as I'd have hoped....

Fred the evil puppet (author)osi2011-07-19


osi (author)Fred the evil puppet2011-07-19

Also was sarcasm... lol and the V2 is up (just pictures at the moment) so take a look!

Fred the evil puppet (author)2011-06-05

yet another peice sacrificed to the knex god...

osi (author)Fred the evil puppet2011-07-18

Hopefully your speaking of the white rods, cuz v2 is coming out later this summer... Its mostly done, and as far as I can foresee, will only require cut white rods.

Fred the evil puppet (author)2011-06-05

usp .45 meets glock 18.

osi (author)Fred the evil puppet2011-07-18

I appreciate the period at the end of that sentance. Why? becuase that sentance should be read "USP .45 meets Glock 18, Period." You hit the nail on the head. btw, sorry so late.

kittensare (author)2011-02-26


osi (author)kittensare2011-03-02


oscartd (author)2011-01-05

Hi I'm new here but could u make a rifle based on this (could be called the UKR)?
good job 4.5 *

osi (author)oscartd2011-01-11

I dislike rifles... I can never get enough range on mine... my barrel's always dis-allow the bullet to leave... so... pistols :) But if you want you could probably add a stock to it!

dillon27 (author)2010-10-24

do u have to have fake lazer?????

shoopdawhoop13 (author)dillon272010-10-30

Nah. But, due to the fact that this gun looks very similar to the Heckler & Koch USP .45 caliber pistol, it looks much better WITH the lazer, like its real life counterpart.

osi (author)shoopdawhoop132010-12-21

the fake laser is needed... it connects the trigger guard to the gun... but nice try!!

osi (author)dillon272010-12-21

Yes, you need the fake laser... sorry, if you don't like the green thing on the end, you can take the green thing off... but the trigger guard is connected to the fake laser which is connected to the whole thing... I mean you could take off the whole laser-trigger guard thing, but what good is that?

rootbeer96 (author)dillon272010-11-01

nice gun 1 star :( lol did i say one i mean 5 great job :)

osi (author)rootbeer962010-12-21

thanks! and sorry so late!

totoandamigo (author)2010-09-03


osi (author)totoandamigo2010-09-03

Thank you kind sir! and finally 24 days later... a comment!

rootbeer96 (author)osi2010-11-02

do the 2 sides have to be different

osi (author)rootbeer962010-12-21

Yes, they do, I designed it to be a form fit handle for a righty... if you are a lefty, then sorry first of all, and second of all, just flip the side that the side things are on.

Senior Waffleman (author)osi2010-10-19


knexsuperbuilderfreak (author)2010-11-17

its ok but i think it is more like a super beefed TDS and what do you meen by "universal"?

Um, It shares very little with a TDS... The only EXACTLY the same parts are the first half the barrel and the trigger... it is a different handle, and fore barrel... But yea I guess it could be considered a "super beefed TDS"

I was actually trying to merge the best things about the TDS and the GD1
I built both guns, and liked the larger round, removable mag of the GD1 and the compact size of the TDS.

as for the "Universal" portion...
after I built the gun it resembled a "USP .45" (let me make this clear, this was not a "replicate a USP .45" project, like I said it was to merge the best parts of a TDS and GD1) I figured USP and UKP went well together. USP stands for "universal self loading pistol" and UKP is "universal knex pistol" so yea, thats where that came from.

About This Instructable




Bio: I've been building and engineering since as far back as I can remember. My first building toys were those wooden blocks, and at age ... More »
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