K'NEX SL8 (Build)

About: K'NEX gun builder here at Instructables. More or less retired from the community, but I still pop in now and again.
One of the biggest projects from The Red Book of Westmarch is now here, with a full set of instructions, the H&KSL8. Built at the request of JonnyBGood, this K'NEX SL8 does not disappoint, with its comfortable grip, great range and good looks. Not only is it reliable, but it is efficient and accurate, and is a wonderful target practice gun.

  • Good range: 50 ft. +
  • Looks almost exactly like a SL8
  • Carry handle (V.1, pics 1 - 14)
  • 10 round magazine
  • Great pin-pull
  • Great stock
  • Overall comfort
  • Highly customizable body

Note: This gun is highly piece consuming, if you don't have a large amount of K'NEX parts, only build the magazine and main body (the area between the handle and where the internal barrel begins). This gun also uses a large amount of broken pieces, few are necessary.

Lets move onto step 1!

Step 1: Main Body

In this step, you are going to be working on the main body, or, rather, the right hand panel. Keep all of the blue rods placed in this step in mind, all of them are used for a certain reason. Check each image throughout this instructable, as many will have image notes.

Step 2: Internals (Part 1)

This is just part one of two that are about internals. Keep the image notes in mind, as they will help you throughout this instructable.

Step 3: Handle / Grip

Now we are gonna work on the handle/grip area. Or rather, the internals in that arena. I do believe that all the broken pieces are needed in this step, but check the image notes for more info on that.

Step 4: Stock Internals

In this step, we'll be working on the stock. Now, a lot of these pieces are "filler pieces" as it were. Many of them are not necessary, and I will label them as such. Check out the pics and their image notes, and if it says "not necessary" you don't have to put them on your gun.

Step 5: Carry Handle

This step is just about the forward area of the carry handle. Check out the pics for more info.

Step 6: Internals and Main Body (Part 2)

Now we arive at part 2 of the main body and internals. Just follow along with the pics and image notes.

Step 7: Magazine

This step is all about the magazine... duh. This part is really customizable, as you can make the magazine longer or shorter, its up to you. In fact, this whole gun is really customizable.

Step 8: Extras / Finishing Up

So, this is the very last step, and in this step you will be doing just as the title says, finishing up. You will be adding the side panels, extras, rubber bands, and firing pin. If you needed any help throughout this whole gun, just drop me a note on the comment section below this instructable, and I will "assist you shortly."

Enjoy your gun, get me some pics if you can, and a review forum topic would be great!

-The Red Book of Westmarch



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    28 Discussions


    5 years ago on Introduction

    If you could, could you give an exact (or near exact) piece count? I am gonna make this after I order my new k'nex.

    Yeah so I'm gonna order about 300 green rods (which makes my total to a whopping 500 green rods :])

    Also, how many green rods do you have? I really want to know...

    3 replies

    I don't think that I could give you a piece count of this gun, it is just so massive.

    As to green rods, I think I have about 750 to 780. Not to many, and I would like to get more, but is suffices. I'd love to have about 1,500 green rods and at least 5 black rods (for firing pins) so I could have more than one gun at a time. But, that is just a dream. =D

    The Knex Inventor

    2 years ago

    Very nice model! I may have to build this sometime.


    4 years ago

    I love how the SL8 is just a heavily modded G38c haha


    5 years ago on Introduction

    i made this gun i find that the mag is not very good at keeping the shells in the right place and i also find that the shells like to stick to the top and not shoot out

    3 replies

    Hey dude! I'm back!

    I am asking mikeasaurus for my old account back, which I should get real soon!

    (Thanks for supporting me)

    No problem. Seeing things like this really make want to pop out my kne'x box and start building like crazy. Unfortunately I have little time to do so.

    Keep up the great work!