Z3 Knex Gun (3-Barreled Semi-Auto Pump Action Revolver)




About: I paint, write music, and used to build knex guns. I have a Bachelor's Degree in Studio Art. - updated 5/7/2014
After much anticipation I have finally posted my Z3. WARNING: This gun is not for new builders. The instructions get difficult in the last couple of steps because I was having a hard time with them and I've taken far too long with this, but I should have given you all the information you'll need to make it function. Also be warned that this takes a ton of blue clips (about 30 I think).

This gun fires three rounds semi-automatically for each pump. It has 40 or so feet of range when you use the proper elastics (use ones that look like the kind I used). The long front end is on there to allow you to rest its weight on things (the front rest combined with the curved butt allow you to keep all the weight off your hands when you are stationary. Although not a great war weapon as the trigger mech is touchy, it weighs 9 pounds and is top heavy. Fun engineering and fun gun though.

Firing Demonstration VIDEO:

Step 1: Handle

1: Build this.
2, 3: Build this.
4: Connect.

Step 2: Pump

1: Build this.
2: Build this.
3: Build this.
4: Slide part from step 3 onto part from step 2.
5: Attach a white connector to the yellow rods as shown.
6, 7: Continue to attach white connectors until the row is filled.
8: Add the rest of the pieces to complete the plate (it should be the same as the one on the other side when finished).
9, 10: Insert the pump.

Step 3: Butt

1: Build this.
2: Build these (7 layers)
3: Slide parts together.
4, 5: Push in the yellow rods that are attached to the 7 layers.
6, 7: Attach the connectors shown (don't attach the small green rods yet)
8: Push the connectors in place as shown.
9, 10: Add the small green rods.

Step 4: Block Structure

1, 2: Build this.
3, 4: Build this.
5, 6: Connect.
7, 8: Add outer layer as shown one piece at a time on the RIGHT side only (make sure that you are adding the parts to the correct side).
9: Copy the panel that you just added on the right side to the left side while leaving out the two connectors and attaching green rods as shown.
10, 11: Build this.
12: Nestle it in place.
13: Add two white connectors and their attaching green rods to complete the left panel.
14: Build these three blocks (add cut in half green rods or cut the tips from longer rods to put on the tops of the blocks in the orange connectors for strength).
15: Insert them as shown.

Step 5: Top Pins Guide

1-4: Build this.
5-7: Build this.
8, 9: Connect.

Step 6: Bottom Pins Guide

1-3: Build this.

Step 7: Trigger Mech

This step is going to be difficult as this part of the gun is very complex and asymmetrical. I did the best job I could but some of the parts aren't even in these instructions so you'll have to do a little bit of figuring things out on your own. The grayed out areas are only there to make it easier to see things.

11-13: The blue rods in the images don't need to be blue rods, but do need to be cut rods.

Last photo: Before you close the mech up, make sure that it's done to the best of your knowledge and that it will work.

Step 8: Firing Pins

1-4: Build this.

Step 9: Turret

Step 10: You Figure Out the Rest

Lol, sorry, but I had a hard time with these instructions. Please look at every photo so that you can read all the notes.



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    52 Discussions


    Reply 5 years ago on Introduction

    Next time, make a 18 round grenade-shooting true trigger semi-auto removable mag turret-fed bolt action (pump action no necessary, but desired) gun. The Z3 just wasn't big enough for me

    Much Bigger.jpg

    6 years ago on Step 10

    lol this step might take... a couple days, thanks for the clear instructions =D

    5 replies

    Reply 6 years ago on Step 10

    Yes, I know, I'm sorry. I did warn about it in the intro though.


    Reply 6 years ago on Step 10

    Oh, lol i didnt read that. And i gave up, theres too much unknown


    Reply 6 years ago on Step 10

    I don't know what experience with knex guns you have so I'm not sure if this applies to you or not, but this gun is a difficult build to start with. Start simpler if you are in fact new to this. I'm sorry it didn't work out for you.


    Reply 6 years ago on Step 10

    Yea, just don't have the time or patience. I'm not terrebly new to knex, I've been around for a while, but haven't made an account until now. The only reason i've built this gun is for me to understand the mechanics and I understand them now, so it wasn't a complete waste. Thanks


    Reply 6 years ago on Step 10

    Oh, okay. You should build Sharir's S3 if you want to learn about some serious mechanisms. The S3 is a continuation of my 3252 project which the Z3's trigger mech derives from. So the Z3 is just an offspring of the S3.