The KING of K'nex RBGs: the Gnasher Shotgun

Introduction: The KING of K'nex RBGs: the Gnasher Shotgun

About: I like to think of myself as someone who only satisfied with high quality projects, and "whats's it matter to ya, when you got a job to do, you got to do it well, you got to give the other fella hell!" - Gun...

This is my favourite gun I have ever made (out of k'nex). It is a working model of Gears of War's Gnasher Shotgun (my fav video game gun).

This is a 8 shot semi automatic RBG. Different from other RBG's, you must break the lever (bring it forward) to initiate another shot. The gun is capable of taking heavy pressures, so feel free to lay on the elastic power.

I apologize in advance for some of the pics having poor picture quality. Just ask if you need clarification on any of them.

Hope you guys enjoy this as much as I do.


Ps: if you hold the lever forward and then shoot, all the elastics fly off at once.

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Step 1: Build the Hand Guard (lower Part of the Lever)

Build exactly what you see here to construct the hand guard part of the lever (the part you put your hand in. The upper part also acts as a trigger guard.

Step 2: Build the Dog Carrier (upper Part of the Lever)

Build what is depicted below. This part moves the function that allows the shotgun to be a semi-auto.

Step 3: Build the Cog Mechanism, the Trigger and the Cog

The Cog (right)

This is where all the elastics fit on. Note the double white combination for more strength.

Trigger (left)

The simple yet strong mechanism that initiates the firing

Cog Mechanism (middle)

This part here directly touches the cog when loaded, and is rotated out of the way to allow the gun to advance the cog. Note the white rod (acutally black)- make sure this part is inserted through the three grey connectors- it gives the gun its strength to withstand pressures.

Step 4: Build the Foreward Thing (does Nothing)

Build this part. It is added onto the near end of the barrel. It exists purely for aesthetics.

Note: whenever you see the large blue panel, it is simply there to prop up the part- it isnt part of the design.

Step 5: Build the Foregrip

This is the part that you hold onto. It is very rigid for maximum grippage (is that a word?)

Step 6: Build the Pistol Grip

This is the pistol grip. You will need a bendy-white rod (actually purple if you have it) for the thumb rest.

If this grip seems too thin, it technically is, because the back of the lever thickens it when it is unbroken (in the rearmost position)... just trust me on this one.

Step 7: Build the Mechanical Walls

These two walls house the mechanics of the gun, so it is especially vital you don't screw this up.

Step 8: Beginning Assembley: Attach the Grip to the Right Mech. Wall

Here, simply snap on the grip to the right mechanical wall.

Note: I didn't realize you needed the green connector, so add it in. this will snap into the trigger axle. (shown below)

Step 9: Insert the Cog Wheel and Trigger

Insert the Cog wheel into the cnetral white (or black) connector. Make sure that the blue spacers are still in place.

Instert the trigger into the white (or black) connector closest to the grip. As noted earlier, the green connector snaps into the trigger axle. (the side not snapped into by a grey connector)

Step 10: Attach the Upper and Lower Parts of the Lever

Now, attach the upper and lower parts of the lever.

Step 11: Insert the Lever

Now, insert the lever into the leftern white connector. Make sure it is the blue rod, not the yellow rod with the spacers.

Step 12: Build the Mock-Loading Port (almost Forgot!)

Build this simple device. When broken, the lever will bring this down-mimicking the real action.

Step 13: Connect the Cog Mechanism and the Lever

Simply connect the two grey connectors with the green rod to have the lever mechanism complete.

Step 14: Insert the Mock-Loading Port

Insert the mock-loading port into the right-most green connector near the thumb guard. Then, with slide the grey connector at the end of the movement arm into the white (or black) rod located just below the lever axle.

Step 15: Attach the Left Mech. Panel

Now, attach the left Mechanic panel. Make sure all the axles and rods line up properly so everything works smoothly. You can try out the action now.

Step 16: Build the Top Rail

Simply build this top section of the gun.

Step 17: Build the Barrel

Now, this may be complicated, but try it out. Build this system, and it will become the barrel.

Step 18: Build the Mock-lever Arms (forgot This... Whoops)

Build this simple attachment. It will be added in the next step.

Step 19: Attach the Mock-lever Arms

Attach this to the protruding green connector on the middle of the lever. Then, connect the green rods on the end of the green connectors to the grey connectors (45 degrees) on the top of the now concealed lever.

Step 20: Attach the Foregrip to the Barrel

Now, snap on the grip- three of the orange connectors behind the first white (or black) connector.

Step 21: Attach the Top Rail to the Barrel/Grip Assembley

Now, just connect the top rail to the barrel assembley.

Step 22: Attach the Left and Right Sides of the Gun

Now, connect the left and right sides of the gun where you need to.

Step 23: Attach the Useless Forward Attachment

Before you can attach the piece, you need to install 4 small black connectors (see below). Then slide on the attachment with the corresponding holes in the upright parts.

Step 24: Slide in Four Blue Rods Into the Top of the Gun

Now, slide in four blue rods into the corresponding holes. The rod at the rear of the gun requires three grey connectors to be snapped in, and the forewardmost blue rod snaps into the 45 degree slot of the upright yellow connector.

Step 25: Attach Mounting Connectors Onto Blue Rods

Now, attach connectors in the fashion as you see below, sorry about the bad pics.

Step 26: Attach Upper Rods

Now, attach mainly grey rods into the connectors you just installed... you're done construction!

Step 27: Atttach Elastics

Now, just attach elastics onto the trigger and cog mechanism.

Step 28: Loading

Now, to load, break the lever forward, and hold it there.

Load an elastic onto the rearmost accessable notch on the cog wheel. To load another, rotate the cog wheel back until the trigger locks it into the next place.

Then, return the lever into the unbroken position.

Step 29: Shooting

Now, pull the trigger and then break the lever until you hear a click and see the cog rotate foreward to re-advance the cog wheel.

Or, as I mentioned earlier, you can break the lever, hold it there, and then pull the trigger to shoot off all loaded elastics at once.

Now go shoot stuff.

Step 30: MECH. UPGRADE: Overview

With this upgrade, I reinforced the lever and dog carrier mechanisms because under intense pressure, they fail. So, without further adieu, here it is.

All the parts you see have already been upgraded, so try and follow along the best you can, I'll try and be descriptive.

Step 31: MECH. UPGRADE: Remove Mock-Lever Arms

Simply detach the moch lever arms to gain access behind the mechanical wall.

Step 32: MECH. UPGRADE: Remove the Right Mech. Wall

Remove the right mechanical wall to gain access to the lever and dog carrier mechanims.

Modify the existing mechanical wall you just removed to look exactly like the one below.

Step 33: MECH. UPGRADE: Remove Existing Dog Carrier and Lever

Now, just remove the existing dog carrier and lever mech so you can modify them.

(shown is the already upgraded dog carrier and lever)

Step 34: MECH. UPGRADE: Modify the Dog Carrier

Now, modify your existing dog carrier so it looks like this one. Also, build the extra 2 arms. (shown below the dog carrier)

Step 35: MECH. UPGRADE: Modify the Lever Mech

Now, just modify your lever mechanism so it looks like this one.

Step 36: MECH. UPGRADE: Attach the New Mechanisms

Now, as before just attach the mechanisms together using the arms. Then, just slide the extra arms on the yellow rod and white rod respectively. (they do not snap on, so they may fall off as you put them in the gun, but once in they retain their positions)

Step 37: MECH. UPGRADE: Modify the Left Mech. Wall

Now, modify the left side mechanical wall so it looks like this one (in the background)

Step 38: MECH. UPGRADE: Insert the Parts

To insert the parts, just re-position the parts as you did before, with the exact same axle holes. (don't forget to line up the mock-loading port arm with the old axle!)

Step 39: MECH. UPGRADE: Attach the Left Mech. Wall

Now, just re-attach your newly upgraded left mechanical wall with the old snap areas.

Step 40: MECH. UPGRADE: Re-attach Elastics and Mock-Lever Arms

Now, just re-attach the carrier elastic and trigger elastic with in the old places, and the mock-lever arms, and you successfully upgraded your Gnasher to a stronger model.

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    311 Discussions


    This gun works amazingly and is a great replica. Great job. I moded it for pump action with a simple lever system and strengthened everything so it holds like 30 bands. XD


    8 years ago on Introduction

    ive built it all, followed instructions, but my trigger doesnt fit in like yours does... i really dont know what to do. so its all built perfectly, but it just cant shoot. so overall AMAZING replica of the gnasher


    8 years ago on Step 5

    yeah how does that bottom part connect to the top part


    9 years ago on Introduction

    Semi automatic shotgun, unless theres buck shot, multiple projectiles are fired.


    9 years ago on Introduction

    I want to build this but it looks like more parts than I have right now and 40 STEPS wow seems hard


    11 years ago on Introduction

    Nice gun, steps a bit unclear but I managed to build it. It does not have semi-auto firing, You must cycle the gun.


    Reply 10 years ago on Introduction

    in blatent terms it is semi-auto cause you dont need to but a new bullet in every time


    Reply 9 years ago on Introduction

    Correct. Any weapon that requires manual cycling of the operating mechanism and allows continuous discharge of several projectiles is known as a semi-automatic weapon.

    If this were a one-shot weapon, it would not be. Further, if this gun were to discharge multiple projectiles in quick succession via one trigger pull, it would be an automatic.

    But you guys know that.

    I'm just glad to see so many people are still interested in this gun. I regret selling my 25 000 pieces of k'nex now, I have a jonesin to make this again.


    11 years ago on Introduction

    I made some upgrade my self: i made it longer the middle 2 rows whit connerctors and rods so rubberbands don't get squeezed and slow them down and the bi-pod from morretti SR-4 just for some fun Ow and i still need to add the mech upgrade. And whit the right rubberbands 6-7m almost accurate.


    Reply 9 years ago on Introduction

    This is a pretty awesome mod to my original design dude (or gal).


    Reply 10 years ago on Introduction

    it is a little of it is more like 5m if you got the right rubberbands

    well i love rbgs mostly semi auto but i wanted to u know have a pump the make the exprince better u know soo its the lever makes it like a real good gun so ima gonna get a 5 tubs of kenex soo it better be worth it................................. and trust me i will upgrade it but the crank stays u rock XD.. upgrade the gun so its longer and more aqurate so KEEP IT UP