Introduction: K'nex FN2000

Picture of K'nex FN2000

This is a Rubber Band Gun that is loosely based off of the Belgian FN2000, below are two pictures. One is a real FN2000, the other is my K'nex one. It is an 8-round cog-driven RBG, it can fire about 30ft max., (better than most of the rod firing guns on this site) and accurately at 20ft indoors. I recommend that you use #16 rubber bands mainly because they are the only ones that I have that are suitable. Please comment, rate, and tell me about any mods or improvements on the gun or if there is a part of the instructable that you do not understand (no not do any of the previously mentioned actions if all you are going to do is badmouth K'nex in general).

Danke und gute Nacht,


Step 1: The Frame and Trigger.

Picture of The Frame and Trigger.

This is the frame, which you might have guessed from the title of this step.

Picture 1: This will be the right side of the frame.
Pictures 2-5: Close-ups of the right side of the frame.
Picture 6: Grab these, they will hold the mechanism later.
Picture 7: Put the pieces here.
Picture 8: Put two spacers on the upper piece.
Picture 9: Add the cog and two more spacers.
Picture 10: Make the trigger.
Picture 11: Be sure you do not add green rods on the sides.
Picture 12: Now slide it on to the blue rod (The blue rod will be slid into the half circle). Be sure that you put green rods into the holes.
Picture 13: Add two rods to these spots and add a rubber band to the rods.
Picture 14: The left side.
Pictures 14-17 : Eh, close-ups of the left side. Exactly the same as the right side, but without the orange rods sticking up.
Pictures 18-23: Clamp the two sides together.
Picture 24: Now add a spacer and a connector to each blue rod.

Yay, it is almost done.

Step 2: The "Barrel"

Picture of The "Barrel"

This is the "barrel", it is for hooking the rubber bands on.

Just follow the pictures and attach it as shown.

To load, you hook the rubber band on to the barrel, then to the cog, then pull back on the cog. Repeat until you have attached 8 rubber bands. Pull the trigger to fire.


Doc Penguin (author)2015-06-21

it lacks a mag.

bu otherwise it is pretty much the same

poellmac (author)2010-11-27

theres no mag

gibbo_gunner2496 (author)2010-08-29

an educated life, in which he can speak english.

moishyb (author)2010-08-23

cool gun!

Whaleman (author)2010-08-20

And you have a loose grasp of the English language.

Whaleman (author)2010-08-14

Well, good sir, put into that context, it does seem reasonable to assume that the ice has gone rotten. After all, this pie weather has caused a certain set of headphones take flight. Highly unreasonable, I agree, for the aeroplanes are all over the place and not a single one has roasted tissues, for the paper tells me so. In conclusion, we must stop the Decepticon, else on the Santa Maria the waffle cones will revolt against the kindhearted ligers of this fine establishment.

Whaleman (author)2010-08-02

What doesn't fit where? I don't know what you're referring to.

Whaleman (author)2010-07-31

What does?

~Aeronous~ (author)2010-05-23

 wait is this semi-auto?

Whaleman (author)~Aeronous~2010-05-23

Shoots one rubber band with each pull of the trigger.

~Aeronous~ (author)Whaleman2010-05-24

 so its true semi auto RBG mech? and also will this blow up? all the rbg guns I've made blow up when I pull the trigger.

Whaleman (author)~Aeronous~2010-05-24

This has not blown up on me once.

~Aeronous~ (author)Whaleman2010-05-25

Good. How strong is the RBG mech?

Whaleman (author)~Aeronous~2010-05-25

Strong enough. I couldn't get it to fit eight 7,5 inch bands over a two to three foot distance, but it is good enough for the little bands. Build it and test. it's only a few pieces.

mettaurlover (author)2009-09-06

this is only better than most of the guns because everybody posts what is basically the same crappy gun over and over again. those make up at least 90% of knex guns in this site, yet they should only make up about 2%.

still pretty good fo ran RBG, though.

barrax (author)mettaurlover2010-02-23

and this was published in 2007

this was good stuff back then.

mettaurlover (author)barrax2010-02-23

Yes. That's what I mean. This was probably one of the most complicated guns on the site, and there was probably the same proportion of original k'nex guns to copies with differently colored pieces.

wildar97 (author)2009-08-12

dude you live in russia

Whaleman (author)wildar972009-08-12

dude the hell are you talking about

Whaleman (author)Whaleman2009-08-13

In other words; 'On what are you basing this assumption?'

wildar97 (author)wildar972009-08-12

oh like the gun

ILIKEPIE333 (author)2009-08-01

um... actually it is the afternoon

Whaleman (author)ILIKEPIE3332009-08-02

Hmm. Many things wrong with what you are saying. One, it is not in fact the afternoon, as evident in the time on your post saying '10:52AM'. The other fallacy is that afternoon is the twelve hour period between 12.00 and 24.00, during which most people will go to sleep.

ILIKEPIE333 (author)Whaleman2009-08-03

it was actually around 1 p.m. when I wrote it, the clock is on California time I live on the East Coast

Whaleman (author)ILIKEPIE3332009-08-03

Well good for you, because at the time you posted it, it was near 22.00 in Moscow. Time is relative. It will always be night for someone.

ILIKEPIE333 (author)Whaleman2009-08-04

Well thank you, Mr Relativity, but it wasn't night for me

Whaleman (author)ILIKEPIE3332009-08-13

Should have read it a few hours later, then.

ILIKEPIE333 (author)Whaleman2009-08-04

right now, it is 1:31 P.M. (Wow, its already been an hour since I left NYPUM)

James_Lawrence (author)2009-06-28

must first time ive built an rbg, and its pretty good, im going to make the frame stronger thought it seems a bit weak but anyway, good gun mate 4.5*

Whaleman (author)James_Lawrence2009-06-28

Thanks, this gun was mostly just to test out the mech, as I had bigger plans for a large caliber semi-auto mech that used an RBG to power it.

TigerNod (author)2009-06-09

Too bad its not a real bullpup... That would be cool. 3.5*

Whaleman (author)TigerNod2009-06-09

Technically it is a real bullpup because the firing mechanism (the cog with the bands on it) is above and behind the actual trigger, therefore being defined as a bullpup. But even if it wasn't a bullpup, I invite you to move the cog back a bit and make a new trigger.

TigerNod (author)Whaleman2009-06-10

I see now.

dragonslayor (author)2009-06-07

how many greens

Whaleman (author)dragonslayor2009-06-08

I don't know.

dynno97 (author)2009-02-20

Realistic. Nice gun.

Whaleman (author)dynno972009-02-20

Thanks. As I recall, this was a pretty quick build. I liked the FN2000, and I had been wanting to get one. But what with them not being CA legal and whatnot, I had to build a simple one. I also wanted to work on some RBG mechs, looking for a strong one for a semi-auto "grenade" launcher.

i live in CA too

Yes, we have discussed this not more than a month and ten days ago.


I am still looking but not finding. ($]: (

Money hat? I don't have any ideas, other than just taking a regular mech and making it outrageously wide and reinforced.

No, more of a person taking a miserable break from looking through his pair of infra-red goggles. Either that or a sad deflated burger hat that, although has been pumped full of money still isn't quite right. : )
I am still having a go at the grenade launcher, it now has a long and wide pump a 3 shot tubular mag and an unfortunately awkward feeding lever. I still feel as though we should maybe have attached some sort of feed regulators to the magazines- like a cog that pushes one round through to the barrel but holds the others back maybe.
As for semi auto I have always quite liked the idea of pumping and cocking the gun a number of times before firing and then it acting like a semi-auto when you pull the trigger. But as of yet I am struggling with thinking of how to rotate a heavily loaded cog (I wanted it to be fired without having to refit the elastic bands by using Hack's Spiff system but that would be fire weaker and weaker with every shot, unless you had very high tension for the first shots - which i think would be just too much strain) with a pump and find a 'memory mechanism' as I call it to auto-load the round either that or have a top loader that released a round each time you returned the trigger to its rest position.

I got so exited whist typing that that I shook all the way through.
On a sader note my attempt at a Gatling gun which I had spent weeks on just got crushed when I passed out whilst standing up and crushed it into pieces- I only hope that I can rebuild from old pictures, the range was poor anyway and I could fire a couple of feet to the side because of messy loading!!

Hmm. A feeding regulator would work, and I had an idea for a pump-action one that pushed a round from a magazine into a space that was over a hole. When the round was pushed all the way forward, it just fell into the hole. The semi-auto/pump might work; have the pump go forward, hook a band, then come back to hook the band on the cog while simultaneously knocking the cog back a notch (as one would when normally loading a semi-auto rubber band gun). You would have to repeat this eight times to fully load the gun. A limitation to that, however, would be the bands at the front of the gun. After the first shot, the bands would either be unretrieveable or block the other shots. Would probably work for a pump-action though, IE not semi-auto. The pump would pull back and load the band whilst loading a round from the magazine. Of course, this would assume that the gun had some sort of ammo regulator.

Oh BLOODY HELL I just spent half an hour typing a long reply and when I clicked post it disappeared!!!!!! Damn wireless internet, damn fake security software, BUGGER THEM ALL!! Anyway I went it to several long explanations of having a lever to move the bands out of the way, keep the unfired bands in a compartment away from the one retracting to reduce friction or have a cog as wide as the grenade. You gave me an idea with your 'fall in the hole' thought for a slide loading mechanism that flicks the grenade into the chamber with a lever and a number of other things which I can no longer remember. I finished up by asking you if you had any launchers in the works. Oh and also a thought that I am limited by using the old frame and its jerky slide.

Wireless internet. I has it. Free AVG, too. I don't have a launcher in the works, but I was thinking of starting a crossbow-esque one. Would have a bow that is pulled back before each shot via a pump that would also load a round simultaneously. Have you considered scrapping the old design and starting over, with lessons truly learned? Grenades are only about six layers thick, and I think yellow rods are nine or ten.

A crossbow sounds like a good idea - decent rubber band placement and the bands should return to the same place each time and therefore there should be less chance of tangling. I could and most likely should replace it but I do quite like the free of it and I think the reason that I stuck with it in the first place is that it was there, already made to take grenades and since I never seem to have enough of the right pieces it appeared to be a good base- how wrong I was. The reason for the thickness is all of the moving parts that operate the gun.

Also that I thought tubular was most reliable magazine type for this but like the 19th Century French rifle the grenade can go off during loading or whilst in the mag but luckily the rounds I am using have off-centre triggers so I can push them in the middle with a rod. That I am up to a full yellow rod thick and that I need more layers for reliability but I don't want to go up to a red rod. I am so irritated that I lost that.

"CA" as in Canada or California.

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