The World of K'NEX Guns

About: K'NEX gun builder here at Instructables. More or less retired from the community, but I still pop in now and again.

For some time now I have thought that it would be good to have a thorough, simple, educational, and comprehensive guide to K'NEX guns, anything from the particular type of gun, to the ammunition it uses. In this guide, you will find a list of the different types of K'NEX guns, magazine setups, propulsion options, internals, triggers, ammo, and them some. Without further adieu, lets move on to the first step.

Note: Main picture courtesy of SLDxRaPiiDZz - knex armory V2.0

Step 1: Gun Types

The first thing to do, in building a K'NEX gun, is you need to decide what type of gun you want. The list below is a list of all (at least I believe so) the K'NEX gun types there are, and their description, with a link to one the best versions (in my opinion) of that type of gun (some of them will be mine, no, I'm not conceded):

  • Bolt Action (BA): A K'NEX Bolt Action gun is a gun that uses a bolt to push rounds/bullets/ammo out of the magazine/clip into a separate chamber.

    The S2 (see picture #1) is one of my favorite BA guns. See it here: This is definitely a gun type that you should try, as it is one of the better types.
  • Pump Action (PA): A K'NEX PA gun uses a pump (generally on the bottom - front half of the gun) that pushes the firing pin (see a later step for details about firing pins) back, so that it can be fired again. Some guns even use both the bolt action mech (short for mechanism) and the pump action mech combined. This type of gun is/are generally the fastest firing gun.

    The REMPAR-2 (see pic #2) is an amazing PA gun that you should definitely check out/build. See it here:
  • Slingshot: A slingshot K'NEX gun uses a rubber band as the launching mech. This particular mech holds a band that the user has pulled back to the chamber area, and then when the trigger is pulled, the band launches forward, pushing the ammo with it.

    I am pretty sure that most hard-core K'NEXers will agree that the SRv1(see pic #3) is the best slingshot around. You will find it here:
  • Break Action (BkA): A BkA gun uses the middle of the gun as the "loading bay." When you "break" the gun open, you can insert one (sometimes two)rounds, and then fire.

    Seleziona's Break Action Rifle (see pic #4) is one that I particularly like. Find it here:
  • Simple Pin: A simple pin gun does not have anything special about it. With these guns, all you have to do is pull back the pin and pull the trigger. These guns are my particular favorite, and are mostly found in models/replicas (K'NEX versions of real guns).

    On of my favorite simple pin guns is Senior Waffleman's SCAR-L (see pic #5). Check it out:
  • Lever Action (LA): One of the most uncommon guns, the lever action gun is relatively hard to describe, as I have never built one, and am not sure how they work, and I have never seen a really good working one.
  • Bullpup: A bullpup gun has the mechanism and mag BEHIND the handle. This means that ALL the shooting action is behind the handle/grip.

    My favorite bullpup of all times is Sharir1701's M17S (see pic #6):
  • Plunger: Essentially, the plunger pushes the rounds out of the barrel by being pushed by some other force. See the video below to understand more fully:

Lets move on to step two, as that will give you magazine choices.

Step 2: Magazines

Now that you have a K'NEX gun in mind you kinda need something that is gonna hold your ammo, and thus, you need to decide what type of magazine/bullet-sitting-area you want to use.

Step 3: Propulsion

Now you have a gun and a magazine... but you need something to help you use them. Propulsion. There are two basic types of firing types/propulsion. Pins (pic #1) and rubber bands (pic #2). A rubber band is not used as often as the pin is, as the pin mech is generally easy to use, in collaboration with the rest of the gun you are building. A pin can be built of any rod size (preferably the light grey rod/black rod/orange rod/clear rod. Any size rubber band CAN be use to launch bullets with, but #117 or #64 size rubber bands are generally the best. Picture #1 is of a firing pin of the largest size, it has electrical tape and a broken band to keep it sturdy and strong. The former for strength, the latter for softening the impact of the pin hitting the gun. The 2nd picture is of #117 size rubber bands. These are ones that I like to use for slingshot guns, as they are long, and easy to pull.

Step 4: Internals and Triggers

So, now you have a gun in mind, a magazine that you want to use, you have decided weather to make it a slingshot-like-gun or a pin gun, but you are missing something. That something is internals. Internals are what operate your firing mechanics, which in turn operate your gun.

Now, there are thousands and thousands of different types of internals, and I could not possibly name all of them for you, so I will name the three best and simplest that I can find.

In the first picture you will find a mech that I like to call the "Dr. Richtofen mech." The reason I call it that is because it was designed by dr. richtofen, and is sturdy and reliable. This one would be easiest for newer K'NEXers. Click on the picture to learn more about it. Here is how to build the gun this mech was used in:

In the second picture you will find a mech that was designed by gtrain. Click on the picture to see how it works. Find the gun it was used in here:

In the last picture of a mech designed by Senior Waffleman, and was used in his SCAR-L. It is one of my favorites, and can be used in many guns. Again, click on the picture to see how it works. Here is a link to the gun it was used in:


Aside from the triggers you see below, there is one type of trigger that is most commonly used. It is known as the "True Trigger" (see pic #4). I am not entirely sure who was the first person to build a trigger like this one, but I believe it is the best ever designed. It works on a pivot, and can be made and used many different ways. Click on the picture to get a better understanding of how it works.

Step 5: Ammo

So now you have your gun, your mag, your propulsion system, your internals, but you need something to fire. Ammunition (ammo).

This is by far the most controversial topic in the K'NEX community, as everybody has a different opinion on ammo. I really don't like rod ammo, and I really don't like connector ammo. I feel that a mix of both is the best, but there are many people who disagree with me.

There are four basic types of ammo: rods, connectors, wheels, and a mix of rods and connectors.

  • Rods (pic #2):
    Rods are by far the most used K'NEX ammo. They are easy to use and generally get good range. The two best types of rods to use are yellow and blue, as these get the best range. Anything bigger than these two types create too much drag, and don't get very good range. Any type smaller than a yellow or blue rod don't seem to work very well, and I am not exactly sure why that is.
  • Connectors (see pic #3):
    I would rather use connectors than rods, as they always work better for me, but it is all really based upon opinion. The picture I have shows all the connector types, but the dark grey connector, the orange connector, and the small tan connector (not shown) are the ones that are really used for guns.
  • Wheels (see pic #4):
    This type of ammunition is rarely used, as they require a somewhat large gun. If you take of the tires though, they make a great grenade type ammo. Their circular shape makes them easy to load and shoot, and they generally get good range (sometimes 100 ft. plus).
  • Mixed type (see pics #5 - #6):
    The most common mixed type of ammo is known as oodammo (see pic #5). It gets good range because of it arrow-dynamic shape, and because of its size. I prefer mixed ammo (generally a dark grey connector attached to a little green rod), as it preforms best for me.

Step 6: The Red Book of Westmarch - Out!

Here are links to some other good guides that you should check out:
knexforever's: the complete guide to knex ammunition:
oodalump's: Guide to Performance Knex Guns:
DarkOwlKnex's: The Guide to K'nex Guns:


-The Red Book of Westmarch



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    57 Discussions

    Oh my goodness, that sounds amazing! Does it have a new mech? Seeing something new from you will be amazing! :D I'm kind of geeking out and bracing myself for innovation. I can't wait to see it.


    3 years ago

    Do you know of any good pisols


    5 years ago on Introduction

    You should list more examples of bolt action guns, as the one you did post isn't the best example. The ZKAR and such are much better.

    6 replies

    Well, I don't know if you have built the S2, but if you have not, you might not be in the position to state that. I really do think that the S2 is one of the best bolt actions around, and Sharir1701 said he got (don't take my word for this) 100ft. The ZKAR is not that good, even with more bands than what I put on the S2.

    He didn't. Hardly any guns will shoot that far. If you angle the gun upwards, with tons of bands, and thrust it forward, maybe you could. But most people here vastly overestimate how far guns shoot. 40' is a lot farther than you think it is. And you are the first person I've heard say the ZKAR isn't good, which is odd.

    You don't know that, so prove it that he did not. I am a NCFCA debater, and I have always been taught that evidence speaks louder than the chap who denies. If you want to see what I am talking about, look here.

    A ton of guns will shoot over 40 ft...aiming straight. Dude, I don't think you understand what is going on. XD I would have to disagree with "But most people here vastly overestimate how far guns shoot" as that is simply not true. Careful bro, read what I said, not what you think I said. I did not say that the ZKAR is not good, I just said that, IMO, the S2 is better. I said that the ZKAR is not THAT good. Meaning that it is not better than the S2 in many respects.

    Have you actually measured, with a tape measure or whatever, how far the plastic goes from a level gun postion to when it first strikes the ground? If not, then any claim here is BS. I'm actually wanting to do this now, use the same amount of bands, streched to about the same distance, on my ZKAR, my new gun, and my TR12, and get a 5 shot average distance of them both. Flat, From my shoulder. My wild predictions at this point are 35' for the ZKAR, 30-35' for my gun, and 45' for the TR. I'll use Oodammo with the TR, because that is the most common ammo to use with it.