K'nex Slamfire Burst Rifle: the K2 V.2

Introduction: K'nex Slamfire Burst Rifle: the K2 V.2

About: Sometimes it takes a man to push beyond what he thinks is possible before he realizes that possibility is a mere conception of the mind. Once that barrier is broken, the mind is no longer a hindrance, but h...
Hello Instructables community!  Kinetic here with my newest in a line of innovative K'nex guns: The K2 v.2.

A gun much unlike any other, the K2 v.2 utilizes a two-stage handle pump to fire four shots consecutively with each pump at a range of 20-30 feet.  No firing pins, no triggers, just push, pull, and repeat.  What does this mean?  It means that you can unleash a rain of plastic upon your enemies at a rate of 4 rounds per second (depending on the user).

The key to this gun is in the two-stage handle pump.  Originally designed to rotate a cog, the teeth within the handle are raised when the handle is pushed, causing them to set off a firing hammer consecutively as the pump is pushed.  When released, the teeth are lowered, allowing the pump to slide back past the hammer without any interaction.

I know that 20-30 feet is a relatively low number, but hey, this thing is as close to fully automatic as a practical gun can get.  While building this, I have labeled spots that require improvement, including an area that requires bad K'nex geometry (I'm slightly embarrassed) to function.  I really hope that you guys can build upon the potential that this gun offers, and at some point, my goal for this gun is for it to hit a range of 50ft.  Whether or not that will happen, well, that is up to us, so what do you say we get started!


-No broken/modified pieces!

-Uncontested rate of fire

-Easy to pump

-Lots of room for improvement

-Unlike anything you have ever seen!


-Low turret capacity (try equipping an 18-shot turret)

-Comparatively low range (20-30 feet)

-Small amount of bad K'nex geometry :,(


Hope you like it and I really want to see what improvements you guys can come up with!

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Step 1: The Handle-Pump

Each number descries each following image with respect to order of appearance:

1.  The driving mechanism around which this gun revolves, the Handle-Pump is designed so that it activates only when pushed, and deactivates while resetting, allowing it to slide past the hammer.
2.  The teeth-these are what comes into contact with the hammer, forcing it back and then releasing it.  Build these 
3.  Exterior handle plates-build these.  Take notice to the blue rods on one plate but not the other.
4.  The interior handle plates-build these.  Don't forget the white rod labeled in the image. 
5.  The center handle plate.  Make sure to remember all of the white rods.
6.  The exterior plates of the tooth housing.  Notice that one has rods and one doesn't.
7.  Add the teeth and attach two red connectors to the whit rods as highlighted in the image.
8.  Attach the second plate of the tooth housing.
9.  Attach the interior handle plate to the exterior handle plate.
10.  Attach the center handle plate, along with the tooth housing as shown.
11.  Attach the second interior handle plate.
12. Attach the final exterior handle plate.
13.  Add 2 (one on each side) #16 rubber bands where shown.
14.  Make the rear guide plates.
15.  Attach them to the handle and tooth housing as shown.
16.  Make the front guide plates.  Notice the white rods on one of them.
17.  Connect two front guide plates as shown.
18.  Complete the front guide by attaching the final plate.
19.  Attach the front guide to the rest of the part to complete the Handle-Pump.

You're getting there...let's move on to the Stock.

Step 2: The Stock

Each number describes each following image with respect to order of appearance:

1.  You are going to be building the stock in this section.  Not only is it extremely sturdy and comfortable, but it also serves to house part of the guide for the handle pump, keeping it out of sight.  You may need some pliers for this step.
2.  The exterior plates of the stock.  Notice that one has rods attached while the other does not.
3.  The interior plates of the stock.  Build 'em.
4.  The center plate of the stock.  Fills in the space between the rear guides of the handle pump.
5.  Attach the interior plate as shown.  Also add two blue spacers on each blue rod where shown.
6.  Attach the center plate of the stock.
7.  Attach the second interior plate.  Add blue spacers here as well.
8.  Attach the final exterior plate of the stock.  This is what the final product should look like.

Fingers hurting yet?  Vamanos!

Step 3: The Body

Each number describes each following image with respect to order of appearance.  Given the size of the body, you will be making segments of it, then putting it together at the end of the step.  Parts of the body contain 6 layers for added support and due to the necessity of a sixth layer in some parts.  These layers will be labeled as "extra layers".  You will probably need pliers for this step.

1.  The body of the gun.  Contains the front guide housing, the hammer, and the turret mount.
2.  The front guide housing.  You are going to make this segment first.
3.  The extra layer for the front guide housing.  Take care to include the blue rods where shown.
4.  The external plates.  Take notice that one has blue rods while the other does not.
5.  Connect the extra layer to the external plate as shown.
6.  Make the center plate and gather two red connectors.
7.  Attach the red connector along with two blue spacers on each blue rod where shown.
8.  Attach the center plate.
9.  Attach the second red connector and add more blue spacers where shown.
10.  Attach the final exterior plate.  You are done with the front guide housing.
11.  The lower turret mount.  You are going to make this segment next.
12.  The extra layer in this segment.  Make this.
13.  The external plates.  They differ slightly, so make sure you pay attention to the next few steps.
14.  The internal plates.  Make 'em.
15.  The center plates.  Make these.
16.  Attach the extra layer to the first external plate.
17.  Another view of step 16.
18.  Attach the first internal plate.  Don't forget two blue spacers highlighted in the image.
19.  Attach the center plates where shown.
20.  Attach the second internal plate, along with two more blue spacers.
21.  Attach the final exterior plate.
22.  The upper turret mount.  Top view. *The blue rod is not in the correct location in these images.  Put it in the slot in the green connector to the left of where it currently is.
23.  Side view of the upper turret mount.
24.  Underneath view of the upper turret mount.
25.  The hammer housing and main body.  The final segment in this step.  The other segments will be used in constructing this segment.
26.  The extra layer in this section.
27.  The exterior plates.  Take notice of the blue rods in one of the plates.
28.  Make these pieces.
29.  Connect them together like so.
30.  Make this as well.
31.  Make the hammer.  It is important to use a black connector here because they are more dense, and thus will hold more tension.
32.  Make these pieces.
33.  Connect the extra layer to the first exterior plate.
34.  Add the piece made in step 29 and one of the parts made in step 32.
35.  Add the hammer, one of the pieces from step 32, and the piece from step 30 (with this piece, although there are no spacers, make sure that it is one rod's width from the exterior plate).
36.  Connect the upper turret mount to the lower turret mount and attach them to the rest of the body like so.  While doing this, you will experience some "bad K'nex geometry" between the red connector and the turret mount.  This is ok, but if anyone can come up with a fix, please let me know!
37.  Attach the final exterior plate.
38.  Top view.
39.  Other side.
40.  Get this piece.  The stock will connect to the space between the blue connectors, so make sure they remain spaced as shown.
41.  Attach it here.

Still awake?  You're almost there, so let's get on to the turret.

Step 4: The Turret

Each number describes each following image with respect to order of appearance:

1.  The tr8 turret, everybody's favorite.  The capacity of this turret is pretty low compared to how fast this gun fires.  Also, the speed at which the hammer fires may cause misfires due to the large space between rounds on the tr8 turret.  A tr18 turret would solve both of these problems.
2.  Make this piece.
3.  Now make 7 more xD.
4.  Make these two pieces.
5.  Attach them to the piece made in the previous step so that they are all oriented in the same direction.
6.  Add the second piece made in step 4.

You're almost there!!!

Step 5: Putting It All Together

Each number describes each following image with respect to order of appearance:

1.  Place the turret on the turret mount and secure it with a tan clip facing outward.
2.  Make sure the band is under the tan clip.
3.  Slap a wheel on there for good measure.
4.  Attach the stock as shown.
5.  Make sure it connects between the spacers as discussed previously.
6.  Attach the front guide housing where shown.
7.  Insert the handle-pump so that the rear guides slide into the stock and are separated by the stock's center plate.
8.  Lift up the front of the handle-pump and slid it back and into place.
9.  Make this piece.
10.  Attach it as shown to the front guide housing to secure the handle-pump in place.

Just have to put some rubber bands on there and we are dunnarooski!

Step 6: Band Placement

Each image describes each following image with respect to order of appearance:

1.  Because of the slight misalignment with the turret and the hammer, put two #64's (one on each side) where shown to realign the system.
2.  Get two # 64's and lay them on the ground like so.
3.  Fold the bottom one through and over the top one, and then through itself.
4.  Pull the bands tight.  This is the maximum amount of rubber bands you will be able to use with this gun.
5.  Thread it through the hole in the hammer as shown.
6.  Stretch both sides of the band down to the front of the gun.
7.  And hook them here.

And you are done!  To load, just turn the turret a couple revolutions clockwise, put in a bullet to keep it in place, and load the rest of the shots.  To fire, just push the pump forward.  It's that simple!  Enjoy!


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    33 Discussions


    2 years ago

    I made it with the tr18 turret. When it fires, the hammer misses 5-10 bullets. Is there any way to prevent that?


    4 years ago

    AMAZING GUN! And amazing music in video... My favourite band is linkin park as you can tell by my name xD


    6 years ago

    i like it!!!!


    7 years ago on Introduction

    whoa i feel so stupid i never knew you posted this lol. nice i guess.


    Reply 7 years ago on Introduction

    Haha yeah its been up for a while. I was hoping that someone might be able to improve upon it sometime...


    Reply 7 years ago on Introduction

    yeah i can see, but i never think i quite saw you posted it. whatever... that's just me being stupid lol. i think you've done a pretty good job, don't know if there's much to improve on it...


    Reply 7 years ago on Introduction

    Ive got a TR18 turret made and ready to go on, but have yet to fit it properly. Put it on briefly earlier and it didn't rotate properly, so will take a look at it tomorrow


    Reply 7 years ago on Introduction

    Huh...thought that a tr18 turret was the same diameter...but I've never made one so that figures. Well let me know how it goes.


    Reply 7 years ago on Introduction

    Its a bit larger than the 8 shot turret :/. I'll post a comparison picture if i remember


    Reply 7 years ago on Introduction

    With these two pictures you can see that there's a difference in size - not fitted the 18 shot yet as i was having problems when i was trying it :/


    Reply 7 years ago on Introduction

    That looks awesome man. How does it work?


    Reply 7 years ago on Introduction

    Works pretty good - the turret is a bit wobbly, so need to try and strengthen it. You can only fit 17 shots into it as the "bullet" stop is in the way of the last shot. Will try it out again and let you know how it performs :)


    Reply 7 years ago on Introduction

    Wow...i didn't think the difference was that big.


    Reply 7 years ago on Introduction

    If all the 2 way connectors on the 8 shot were yellow connectors, then it would have the same diameter as the 18shot - think that's about right :P