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.

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.
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Doc Penguin2 months ago

it lacks a mag.

bu otherwise it is pretty much the same

poellmac4 years ago
theres no mag
moishyb5 years ago
cool gun!
~Aeronous~5 years ago
 wait is this semi-auto?
Whaleman (author)  ~Aeronous~5 years ago
Shoots one rubber band with each pull of the trigger.
 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~5 years ago
This has not blown up on me once.
Good. How strong is the RBG mech?
Whaleman (author)  ~Aeronous~5 years ago
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.
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.
and this was published in 2007

this was good stuff back then.
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.
wildar976 years ago
dude you live in russia
Whaleman (author)  wildar976 years ago
dude the hell are you talking about
Whaleman (author)  Whaleman6 years ago
In other words; 'On what are you basing this assumption?'
oh like the gun
ILIKEPIE3336 years ago
um... actually it is the afternoon
Whaleman (author)  ILIKEPIE3336 years ago
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.
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)  ILIKEPIE3336 years ago
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.
Well thank you, Mr Relativity, but it wasn't night for me
Whaleman (author)  ILIKEPIE3336 years ago
Should have read it a few hours later, then.
right now, it is 1:31 P.M. (Wow, its already been an hour since I left NYPUM)
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_Lawrence6 years ago
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.
TigerNod6 years ago
Too bad its not a real bullpup... That would be cool. 3.5*
Whaleman (author)  TigerNod6 years ago
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.
I see now.
how many greens
Whaleman (author)  dragonslayor6 years ago
I don't know.
dynno976 years ago
Realistic. Nice gun.
Whaleman (author)  dynno976 years ago
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
Whaleman (author)  The Creatornator6 years ago
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.
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