About: I make K'nex guns, specializing in semi-automatic, RBG-Slingshot hybrid systems which i use in most of my guns. Note: I am not responsible in any way for any damage, injury, or death caused by my Instructab...

This is my MSMG (Masterdude Sub-Machine Gun). It has a true trigger and like most of my guns is semi-auto (there is some controversy over the term semi-auto but according to me in K'nex it means that every time you pull the trigger, a shot is fired)

-Removable magazine
-Adjustable stock
-Rather easy to use
-Adjustable cheek rest (when stock is extended you can slide it where you like it)
-True trigger

-Handle might be uncomfortable for some people
-Can be hard to load at first (But becomes easier with some practice)

Image 1: Stock extended.
Image 2: Stock compacted.

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Step 1: Main Body: Making the Components

Make the following. Each will be assigned a letter for identification:

Image 1: Make 1. (Part A)
Image 2: Make 1. (Part B)
Image 3: Make 2. (Part C)
Image 4: Make 1. (Part D)
Image 5: Make 1. (Part E)
Image 6: Make 1. (Part F)
Image 7: Make 1. (Part G)
Image 8: Make 1. (Part H)
Image 9: Make 1. (Part I)
Image 10: Make 1. (Part J)
Image 11: Make 1. (Part K)

Step 2: Main Body: Construction

Follow the images:

Image 1: Add white and blue rods to part A where indicated.
Image 2: Attach part B and add white and blue rods.
Image 3: Attach part C,  white rods, and 2 blue spacers.
Image 4: Add parts D, E, F, G, and H.
Image 5: Add part C, blue spacers.
Image 6: Add part I.
Image 7: Add parts J and K, and tan clips.
Image 8: Add metallic blue clips.

Step 3: Stock: Making the Components

Make the following. Each will be assigned a letter for identification:

Components A: Follow images 1-3 to make this component. Make 4 of these.

Component B: Follow images 4-6 to make this component. Make 1 of these.

Component C:  -Image 7: Make 2.
                             -Image 8: Make 3.
                             -Image 9: Add blue rods.
                             -Image 10: Add 3 parts as shown.
                             -Image 11: Add the last part.

Step 4: Stock: Construction

Follow the images:

Image 1: Take 2 of the earlier made parts and add 7 orange connectors.
Image 2: Take earlier made parts and connect as shown.
Image 3: Add 5 orange connectors and connect as shown.
Image 4: Connect another of the earlier made parts as shown.
Image 5: Attach all those parts as shown.

Step 5: Magazine: Making the Components

Make the following:

Image 1: Make 2.
Image 2: Make 1.
Image 3: Make 1.
Image 4: Make 1.
Image 5: Make 1.

Step 6: Magazine: Construction

Follow the images:

Image 1: Add white rods.
Image 2: Place the earlier made parts as shown.
Image 3: Cover with the earlier made part.
Image 4-5: Finished magazine with ammo and pin in place.
Image 6: Ammo.

Step 7: Putting Everything Together

Connect the parts you have made as shown.

Step 8: Loading and Firing

This gun loads and fires like most of my guns like my MAR, MAR-2, MSAU, ETC. To load you first remove the magazine and put the pin in place, and then you insert the ammo which is shown in the image below. Then you insert the magazine into the appropriate place until it firmly holds in place. They you push the white rods over the ammo feed out to the side and you take the rubber-bands and hook them on the tip of the barrel and then on the spoke in the back of the gun. Then you push the white rods back into place and pull the pin out of the magazine. To shoot you pull the trigger.

Image 1: Ammo.
Image 2: Loaded. View of barrel end.
Image 3: Loaded. View of ammo feed.
Image 4: Loaded. View of trigger system.
Image 5: Magazine in place. Pin in.
Image 6: Magazine in place. Pin out.
Image 7: First person's view.

Warning- This may cause harm or injury if misused. Do not point it at people. I am not responsible for damage, injury, or death caused by this instructable.



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    37 Discussions


    3 years ago

    I built it, but unfortunately it didn't work for me. I'm sure it's a great gun when it works though!

    I decided to make a parts list while disassembling it.

    -----Rods: 234-----

    Green: 146

    White: 64

    Blue: 19

    Red: 5

    -----Connectors: 210-----

    Grey: 55

    Light Grey 2-Way: 5

    Orange: 25

    Red: 17

    Green: 17

    Yellow: 79

    White: 6

    Blue 3-D: 6

    -----Misc: 26-----

    Y Connector: 8

    Tan Connector: 3

    Metallic Blue Connector: 4

    Male Ball Joint Connector: 1

    Black Hinge: 2

    Blue Hinge: 2

    Blue Spacer: 6

    -----Total: 470-----

    You're welcome :)


    6 years ago on Introduction

    Well, i finally finished it, and it took up 75% of my pieces, not to mention it looks different in some spots, but i love it, and it is Semi auto, if you hook up 4 bands to it, and put them on every other spike on the wheel, it will shoot 4 rounds. (i know this because of a gun i had built a while ago, and this has the same mechanism.

    Thanks. I'm coming out with a new full auto version of this soon. Made a breakthrough with full auto and am making some full auto versions of some of my previous guns along with some new tweaks I've found to be helpful since the originals.

    It's already out, it's the MASMG. These guns can have more than 8 shots, you just rotate them a full turn and start doubling up the bands.


    7 years ago on Introduction

    here's my problem, I follow everything to the letter, but I don't understand how it shoots, it need to shoot the elastic too and it doesn't shoot far...

    1 reply

    Reply 7 years ago on Introduction

    When you shoot the rubberband is probably going to shoot as well but it should hook on to the ammo. The rubberbands should also be rather tight when pulled back for maximum power.

    No. My RBG/Slingshot Hybrid guns can only use connector based ammo. However in some of my other guns you can have some flexibility and can change the tip of the ammo.

    I have a (friendly) war coming up and need a good assault rifle for the job. One of my friends doesn't have any Knex and I need to make his gun for him. So I need a low peices, efficient and reliable Knex assault rifle. Should I built this or the MSAU 1/2, or perhaps the MAR?

    1 reply

    I would recommend the MSAU (both have their pro's and con's) and the MAR's/MBAR's. The MAR's/MBAR's use more pieces than the MSAU's, but the ammo is larger so more power and they have better features like sights, grenade launchers, etc.