M-12 Hunter K'nex Rifle




This is my new K'nex rifle, the M-12 Hunter.

It is a fairly large gun, originally built as a sniper rifle but became a semi-automatic rifle later.
It features a 9 round magazine designed by hack1024x768. It also features a block trigger mechanism connected to a true-trigger, which i know everyone hates, but it works very well, and I myself hate the Sear mechanism.

It has a pretty comfortable and effective stock, but for the younger people you may want to shorten it.
The scope is just for show, I wouldn't recommend aiming with it.

The gun has a very high capacity for elastics, so it can be as powerful as you want.  At first the bolt will seem very hard to pull back, but it is designed so that when you are holding the gun properly (butt in shoulder, rifle straight in front of you) it is very simple to hold the gun with one hand on the front grip, and use the hand on the side of you that the butt is against, and pull back to bolt with that hand. The bolt may seem a little flimsy, but if you have the palm of your hand touching the curved part, and some of your fingers more towards the center, it will work perfectly.

Posing today in the introductory pictures is my brother, Patrick.
The main instructable and design of the weapon is done by me, oharaandrewlp.

Step 1: Magazine Assembly

This is where the blue rod ammunition is stored, it is also the heart of this weapon, that is why we are starting at this area.

Step 2: Firing Tube

This is where the ram rod is inserted. It is also where many of the guns other components are mounted.

Step 3: Bolt

This is a very important component. This mechanism will pull back the ram rod with ease if you do it correctly.

Since this component has been designed as a bolt, there is a lot of pressure on it in ways that it cannot properly handle. A pump component would have been much more efficient, but that is the price you pay for aesthetics. This is why the bolt is very fragile, and you should read teh introduction to this instructable for instructions on how to operate it properly.

This component may be difficult to build due to the reinforcements that I have added to strengthen the bolt. Take it easy and keep checking the pictures, and you should be able to do it.

Step 4: Ram and Combinination With Bolt

This is the ram rod. It is what the elastics are attached to which store the Elastic Potential Energy into it. When it is released, the Elastic potential energy is converted into Kinetic energy of the ram rod.

The rod strikes the blue rod ammunition with this kinetic energy and transfers it to the blue rod. That is what causes the rod to escape through the firing nozzle with great speed.

Easy to make, but make sure that you combine it with the other components properly

Step 5: Outer Chassis

This will house the firing tube.

It will be used as a base for future components, and it will stiffen the firing tube, allowing more components to be built off of it.

Step 6: Block Trigger Mechanism

This mechanism will drop down when the ram rod is pulled back enough. It will lock the ram rod into place and will not release it until the trigger is released.

Step 7: Upper and Rear Chassis

This is a lengthy section.

It deals with three components:

the upper chassis (where a scope can be mounted)
the Rear Chassis mount (where the trigger and rear chassis will be attached
bolt rail (makes the bolt steady, is very flimsy beforehand)

Be on the lookout for three mistakes that I have made. they will be mentioned in the comments, so look for them. They are:

grey connectors on top of rifle
white rod near end of steps
blue spacers on second last step

Step 8: Trigger and Rear Chassis

In this section, you will attach the trigger and the rest of the rear chassis to the rifle. However, adding the second layer of the rear chassis to the rifle can be extremely difficult.

One easier way would be to take off part of the layer and attach that to the main component. It should be easier to then attach the rest to the layer through the back of the rifle.

Step 9: Barrel and Front Chassis

In this section, you will make the barrel and the front chassis of the rifle.

I made a small mistake, I didn't ask you to gather two yellow rods at one point. I will point it out when you reach that point.

Step 10: Hand Guard and Grip

Here you shall make the hand guard as well as the grip.

Step 11: Adding the Elastics

Read the instructions and look at the pictures to find out where to put the elastics and how much to use.

Block Trigger Mechanism:

You must hook the elastic to the ends of the white rod at the top.
Have the middle of the elastic go through somewhere underneath.
you must be careful that it is not too strong or too weak.
if it is too strong, it will be hard to release or pull back the ram rod.
if it is too weak, the block will not slide down and stop the ram rod.

Ram Rod:

For short elastics, hook the end to the end of the orange connector of the rod, and the other end on one of the orange connectors at the bottom of the rifle.

For long elastics, attach the middle to the end of the ram rod, and the other ends to one of the green rods at the bottom.


Place end on the end of the blue rod sticking out of the back of the bolt. Hook it somewhere else, such as around the blue rod of the block trigger mechanism.

Step 12: Loading and Firing


Open the magazine by pulling at the bottom of one of the doors. It will optimally hold 9 blue rods, but you can pull back the rod and add another one, or try to squeeze an extra one in. Squeezing more in will risk the magazine "exploding" when the rifle is fired.

Pulling back the bolt:

Hold the rifle properly. You must hold the front grip with one had, your other hand on the bolt, and the shoulder on that side against the butt. Have the rifle face straight away from you, and pull back on the bolt. Have the palm of your had around the arm of the bolt and have a few of the fingers pressed near the middle of the bolt.

Once the block trigger mechanism is engaged, push forward on the bolt to bring it back to is starting place. This will allow the ram rod to travel as fast as possible.

Doing this will allow you to pull the bolt back quickly (even with may elastics), with only a very small chance of the bolt breaking, and with the highest success rate of the block trigger mechanism engaging.


Aim at a good target (such as a little sister or a poster on the wall or into some cushions, do not aim more than 45 degrees downwards or risk the ammo falling out of the barrel. Pull back on the trigger, and let fly.

Step 13: Scope Mod

This will show you how to add my scope to the rifle. But I do not suggest aiming with it, it is not calibrated to assist with that. In other words, it's just for show.

I did have it all step-by-step before, but my camera's picture card got corrupted, and I have just about had enough k'nex for one day.

I may add more mods later, such as a proper front grip, and I will also add any mods which other users have made of this rifle, so it would just be better to show it to me, and I will add it and give you proper credit.



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    57 Discussions

    jake scythe

    7 years ago on Introduction

    I have am working on a automatic gun/a gattling gun, its working well so far other than the fact I need to be strengthed it or parts of it explode (small parts that make it fire), but trust me it is no some five geared gun with a chain, but have to say that this gun, its impressive.

    1 reply

    7 years ago on Introduction

    The description is wrong, if everyong hates block triggers, then everyone hates pretty much every knex gun made.
    Slingshot mech: trigger BLOCKS the mechanism from moving.
    Block trigger mech (traditonal): BLOCKS a rod from hitting the bullet/ammunition.
    "BLOCK TRIGGER" defenition (to me): BLOCKS the firing mechanism from moving/firing.
    Aside from that, this is a good gun and I intend to build it sometime.

    2 replies

    7 years ago on Introduction

    ur bro looks like me except with short hair and an evil smile -the evil smile is me-


    9 years ago on Introduction

    Due to whining, I have changed the name of this rifle to the M-12 Hunter.  Now you can call it a shark all you want!

    1 reply

    Reply 9 years ago on Introduction

    Ok, please stop calling it a shark now. It's really annoying to get random emails from Instructables telling me that it looks like a shark.


    9 years ago on Introduction

    lol. no offense but in the 2nd pic you look like a major creep.

    James 123

    9 years ago on Step 1



    9 years ago on Introduction

    looks a bit like a battle rifle from halo 3. this is very cool and good looking


    9 years ago on Introduction

     make it like a real sabr. the  longe range barrel and the short range barrel with a connection of 2  pin


    9 years ago on Introduction

    I'm back into K'Nex again (for now) I'm building someone else gun for ideas at the moment. I may try making another instructable in the future.