Introduction: DD-27 V2.75 Compact AST Rifle

Picture of DD-27 V2.75 Compact AST Rifle

This is it. the one the only, the DD-27!. I have worked long and hard on this gun. It is the strongest to date firing pin type K'Nex gun. It works with the most frictionless-to-date barrel for ram guns. The barrel is more then 1 foot long, BUT it is only composted of 12 connectors. shoots the 7 1/2 in. grey rod.

V1.0- Made as something when i was bored, never took it apart.
V1.5- I modified it for some more power
V1.75- Added Perfect Duck's pistol grip
V1.9- Added a true trigger mechanism and a better barrel
V2.0- Significant changes to the front barrel were made, stock was added.
V2.1- Heavily fortified the front of the barrel.
V2.5- Added barrel extension to make it shoot greys harder then the other red rod ammo.
V2.75- Nothing big but i added a chain on the top

Believe me, the power of this thing is unrealistic and you will never truly understand the power without making the gun.

It gets all this power from three things.

1. The barrel does not have that much friction, it still has friction but with only 12 connectors composing the entire 1 foot 2 in. long barrel.

2. It uses the KILLERK pistol type mechanism were the bullet is held in exactly were the ram will make contact with it. But mine is better. There is 1 in. of space between the ball joint(note i used a light grey connector instead of a ball joint) and the connector before it. So the gun does not lose any power before the ram hits the ball joint. Normally it would hit the side of a connector and have to go through the hole in it and that would line it up with the ball joint. And then the ram has to push through the sides of the ball joint. With no connector before the ball joint the ram just glides over the the ball joint, not losing any power, but still hits the rod, firing the gun.

3. It has almost a complete draw back of the firing pin. The block is exactly one grey spacer after the tan lock that holds the ram back. If i moved the block one blue spacer up the firing pin could not be pulled back far enough for the block to engage. This helps because the firing pin has almost a entire grey rod length to speed up and gain momentum that ultimately gives the gun power.

standard round (grey rod)-80-100 feet
sharpened rod 70-90 feet
grey connector on grey rod -accurate to 60 feet!
2 3d blue 7 slot connectors with blue clips all over on it connected to grey rod- 40 feet shrapnel 10 feet away from bullet

stats were taken with two #64 rubberbands tied togeather.
ranges and power may vary.
Please comment and rate!!!

Step 1: Gather Your Parts

Parts list:*

grey-------------------------2(black recommend)

dark grey------------------16
light grey------------------5

tan locks------------------2(one needs to be weakened, see Perfect Duck's twin pistols to find out how)
black hands--------------18
ball joint ball-------------1
blue spacers------------21
grey spacers------------14
flexy yellow rod---------1


*Subject to counting errors

Step 2: Beginning of Barrel and Ram

Picture of Beginning of Barrel and Ram

This is a some what special part. it is one of the only guns that get a complete draw back of the ram. the block on this gun is right before were the ram can not be pulled back any more(a tan lock holds the ram in). So i get almost a entire grey rod length for the ram to speed up.

This as around the easiest part of the entire gun. You need to add tape to the ram, If you don't then you will have broken pieces when you fire the gun.

The one tan lock in the picture is the modified one.

Sorry about this being a big part, but it should not be hard, as this part is not complicated.

Step 3: Make and Add Handle

Picture of Make and Add Handle

Not hard, this is the same as Perfect Duck's handle. Instructions are not that in depth because you can find them on perfect ducks instructable.

Step 4: Add Extended Barrel.

Picture of Add Extended Barrel.

Most important part, this is what gives the gun its power. I explained it all on the intro so just make from the pictures. This is the longest step, i tried to make it as easy to make as possible but pay attention to what you are connecting.

Step 5: Extend Barrel Even More

Picture of Extend Barrel Even More

Yes, the barrel gets bigger. We are going to add more to the barrel and a hand grip.

Step 6: Strengthen the Barrel

Picture of Strengthen the Barrel

Add ons to the barrel. They make the barrel a lot stronger.

Step 7: Add Stock

Picture of Add Stock

Make the stock, its not the best but it works well, and looks cool.

Step 8: Add Trigger

Picture of Add Trigger

Add the trigger

Step 9: Chain

Picture of Chain

Make the chain, and attach were noted in the picture.

Step 10: Ready, Aim, FIRE!

Picture of Ready, Aim, FIRE!

Just attach 2 rubber bands to the ram, and one to the trigger. Then pull the ram back, and push a grey rod into the light grey connector in the barrel. Then just aim and pull the trigger.

Don't get hurt like i did!


ProtectTheAlphaWolf made it! (author)2016-08-16


shieldsam (author)2012-10-18

This thing is lethal - 271 feet with 12 64's tied into 6 strings of two... The pin exploded, but it fired!

DracoUltima (author)2011-10-06

Sorry, for me this did not get your claimed 100 feet, it only hit about 60 at max, and not just that but I had quite a few more bands than you and strengthened everything to a ridiculous degree. The gun is taken apart now to build my rifle, your gun was pretty bad, but going by your instructables, you lack pieces which might be the reason.

dsman195276 (author)DracoUltima2011-10-30

This gun requires the barrel to be completely straight or else it won't fire well. strengthening the barrel will only help if you make sure to keep it straight. I have many reports from people hitting higher then 60 feet, so the gun design isn't the problem. I'd check that all the snowflake pieces in the barrel are smooth, the firing pin is completely straight, the ammo is straight, etc.

Also, you have to make sure the bands are very balanced. If they are puling the firing pin even slightly to one side or the other that will seriously hinder performance.

You should also note, I have much much more K'NEX then is in this gun, butI don't see how that effects the gun at all.


~Aeronous~ (author)2010-08-04

No pin guide?

dsman195276 (author)~Aeronous~2010-08-04

The stock is so weak on this gun that a pin guide would have hurt the power more then helped it.

I seriously recommend building this gun without just because it's really bad. Now the next version of the gun that i made(the Ible for it is probably coming soon. I don't know, I've been saying that for who knows how long now....) has a pin guide because the stock is strong enough to not bend. In that case it probably does help a little, and makes the pullback easier.

~Aeronous~ (author)dsman1952762010-08-05

Umm, well why don't you strengthen the stock. I'll add a (strong) stock and pin guide for you if you want? I'm good with stocks.

dsman195276 (author)~Aeronous~2010-08-05

I've already done that on the new version which isn't posted. You can on your gun but I don't need to you do that for me.

~Aeronous~ (author)dsman1952762010-08-05

Fine then, just hurry up and post it then. Does it have a pin guide? Also, put the chambering mech from the NAR on it.

dsman195276 (author)~Aeronous~2010-08-05

Chambering mech? You mean the stray ball joint shoved in the front of the barrel to take the impact of the firing pin? I hardly call that a mech, and I'd never put one on one of my guns. It's just a crude way of taking the force. that ball joint will eventually break and it probably won't take that long.

I'd be allot more enthusiastic about the NAR if Ooda actually put some thought into how he dispersed the impact instead of shoving a piece in the barrel to take the entire impact force. 

~Aeronous~ (author)dsman1952762010-08-06

Now you are just jealous because it is so much better than this. I have built it 4 times (I only break it 'cos I don't have that many pieces) and I know that it shoots 450+ft with 12 bands. The ball joint won't break, because it hits it side on, study it. There is no hole in the middle. Also, since Ooda put it on the nar, it has a pin guide, and a way better true trigger which blocks further back in the barrel than this.

dsman195276 (author)~Aeronous~2010-08-06

First, This trigger blocks back farther then the trigger on the NAR if you actually look and pay attention at how far the firing pin is traveling. The NAR loses a few connector spaces to a few connections. As for the trigger itself, the trigger on this gun stinks I know that. The new version has a better trigger. It's also notable that Ooda didn't even design the gun.

Second, I really don't care if you think that the NAR is better then this. And if you do, why are you bothering to even post on this gun? AND you went as far as to tell me to "hurry up and post it".

As for the ball joint, you got me that I can't say from experience that I've ever had a ball joint break(I never wanted to risk a ball joint to test it, since I have a limited amount of them) but I have plenty of friends from instrucatables that have told me that their ball joint broke. I have no idea if they put it in the right way or what ever, but there smart so I imagine they did. Saying "the ball joint won't break" is a pretty bold statement.

Honestly if you like the NAR so much, then go build that.

~Aeronous~ (author)dsman1952762010-08-07

I fully support this, I just saw the back barrel and the NAR blocks further than this.

dsman195276 (author)~Aeronous~2010-08-07

Going of of Ooda's pictures of his NAR, this blocks the exact distance back as the NAR, but unlike the NAR you can take the gray connectors off of the firing pin of this gun, effectively moving the distance back two spaces surpassing the NAR's distance. On the NAR you have to have at least two spaces on the firing pin filled so it's the right length for the ball joint in front.

And it's great to know you support this, but i'll let you know right now that I DON'T support putting Ooda's 'ball joint' power taker thing. If I do make something like that I'll actually have it suppress the power instead of just bluntly take it.

DJ Radio (author)dsman1952762010-10-18

Your method sounds wimpy. If you're so worried about the balljoint breaking, just reinforce it by putting the nub of a cut rod in the part where you put the rods in.

dsman195276 (author)DJ Radio2010-10-19

xD well cutting up a rod would defeat the purpose of trying to save my pieces from breaking wouldn't it?

As for it sounding 'wimpy', it'd get the same amount of force Ooda's ball joint can. Just without the chance to break your pieces.

Basically, it'd work like this:

Fire the gun
The Firing pin hits the end of the bullet, firing it. Right after that, the suppressor kicks in, and stops the firing pin from moving so fast. Kinda like if you replaces the front of the gun with Styrofoam. Obviously the implementation of such a system would be nothing like styrofoam, but it would cause a suppression effect close to that type of material. 

I honestly don't see how anybody can object to a system like this. If nothing it's just another advancement we can make in the realm of K'Nex Weaponry. 


DJ Radio (author)dsman1952762010-10-20

Ohhh, I get your idea now. I thought you meant reduce the power.

The problem with that system though is that something like that would tremendously reduce the amount of energy being transferred to the bullet since it would "Absorb" more power than the balljoint on the NAR.

Also, the front of the gun (The parts after the balljoint) take the force, not just the balljoint itself.

~Aeronous~ (author)dsman1952762010-08-08

Oh. Hang on, the distance only counts to how long it takes for it to hit the bullet, so it would hit the bullet and go two spaces ahead, so its not technically two spaces further? Also, have you built the NAR? Because even if you hate the concept, you should still build it because it would probably help you to make a better version of this (DD-27).

~Aeronous~ (author)2010-08-07

Yeah, the NAR blocks further back than this.

Storm950 (author)~Aeronous~2010-08-07

This gun was posted in 2008. Stop being such an arrogant know-it-all and so your research before posting.

sukinmaru (author)Storm9502010-10-03

*sukinmaru likes this*

~Aeronous~ (author)Storm9502010-08-07

'and so your research'??? He claimed this blocked further back than the NAR.

sukinmaru (author)2010-10-03

sweet jesus only 37 green rods! I may actually be able to build this! I have 45 green rods... those numbers better be damn accurate! :)

dsman195276 (author)sukinmaru2010-10-03

My recommendations is to just skip the stock entirely. it's more or less a makeshift stock, and the gun functions just as well without it.

Happy building :-)

sukinmaru (author)dsman1952762010-10-03

I have 3 options:
1) scrap BRKWB2 for parts
2) eBay!
3)no stock :(
k, wait I see hinges. looks like I'll need more anyway... TO THE EBAY CAVE!!

MegaMetal8 (author)2010-08-28

Does this have a bullet lock?

dnmonsen (author)2010-06-17

how far does it shoot?

morgan1210 (author)2010-01-24

 what does AST MEAN

Pizzapie500 (author)morgan12102010-01-24


morgan1210 (author)Pizzapie5002010-02-17


dsman195276 (author)Pizzapie5002010-01-24

 Your right, though looking back this really isn't a assault rifle :-P.

Pizzapie500 (author)dsman1952762010-01-24

Is this a rotating barrel or single shot?

dsman195276 (author)Pizzapie5002010-01-24

This version at least is a single shot. I'm still deciding on the new version whether or not to make it have some type of turret. If I do go for a turret that would probably get rid of the option of grey rod ammo which is really what make the DD-27 what it is.

DJ Radio (author)dsman1952762010-01-26

Nobody uses gray rods as ammo anymore. 

dsman195276 (author)DJ Radio2010-01-26

 ...Then I guess I'm nobody lol.

DJ Radio (author)2010-01-08

You just got beaten by oodalumps.

dsman195276 (author)DJ Radio2010-01-08

Depends on how you define power. I define power as power per rubberband, not max power on the gun. I'm not denying that the gun shot through wood, but keep in mind your comparing two #64's on this gun to 8 on that gun. Ofcoarse the one with 8 will shoot harder, but that doesn't nessarly make it more powerfull.

You could shove 8 RB's on this gun if you wanted and I garentie that it would shoot even harder then that gun(Though the back would implode...).

Thats also shooting Red rods, which are smaller.Though that probably doesn't make a huge difference, it's really hard to say with knex rods. The only thing i can guess that might happen is grey rods would bow out a lot more then reds before actually starting to puncture the wood.

Whaleman (author)dsman1952762010-01-09
Say you have Gun X and Gun Y. X shoots 20 feet per band. Y shoots 15 feet per band. So, at one band, X is more powerful than Y. X can only take one band, while Y can take ten. Is X still more powerful than Y?

According to your logic, the answer is yes.

According to everyone else (insofar as I can tell), the answer is no.

X is not more powerful than Y. X has a max distance of 20 feet, while Y has a max distance of 150 feet. Ergo, Y is more powerful.
dsman195276 (author)Whaleman2010-01-09

Your leaving out many important details.

1. Just because gun y can HOLD 10 band does not mean that it's practical by any means. The TR can shoot through wood with 8 bands sure, but the pull back and bend of the entire gun just makes it impractical to call that a max range. Like I said, I could just as easily put 8 bands on this, but it's just impractable.

2. The difference in how many bands each can take does not differ as much as you think. I normally just use 2 bands on the DD-27, but it could easily hold around 6(I have trouble pulling that back).

3. Again, I will say that this is subjective. I think the big problem with your logic is that there is no max distance. Who says that the TR can only hold 8 bands? and who decides how many bands qualifies for max distance? I can tell you right now I am not strong enough to pull back 8 bands easily with out taking off some of the bands and putting them back on, which would make my max distance smaller then yours, and the max distances of these guns for me much closer.

4. The third thing is ammo. I can only fire grey rods making my ranges smaller already. You would get different max distances for each type of rod and the TR wouldn't be able to fire grey rods straight making it unfair for the TR to use them for any type of max distance measurement.

Thats why I like to use power as power per rubberband. power per rubberband is measurable and overall distances would be a better measurement(no variable of number of rubberbands). Of coarse it's not a perfect way of measuring power, but there isn't really a perfect way is there?

Whaleman (author)dsman1952762010-01-09
1. There is no bend in the gun at all if you put a good stock on. The only bend comes at more than ten bands, and that's only the pin bending. It is entirely practical to have eight bands on it. I can pull back eight bands easily.

2. I was not referring to these two guns in particular. I was pointing out the flaw in your logic; that power is measured per band, instead of the amount of power the gun can take before breaking.

3. There is a max distance. It can be found using physics. It can be easily determined by the number of bands you can put on before the gun breaks. In the case of the Untangle, the pin will snap before the body of the gun breaks. Just because you can't get the 1 MOA groupings an M24 is capable of with M118 ammo doesn't mean that the gun is any less accurate; it just means that you happen to be an inept shooter.

4. Grey rods suck for ammo. Why are you using grey rods? They lack stability. And again, I am not referring to power of a gun with a particular ammunition, or even any two particular guns.

Power per rubber band is not directly proportional. It will level out eventually; maybe not before your gun explodes, but eventually.
DJ Radio (author)Whaleman2010-01-26

The pin on my untangle started bending at 7 bands.

dsman195276 (author)Whaleman2010-01-09

1. I know there are flaws to this type of measuring, I said that in the last sentences in the last comment.

2. You do realize the obvious flaw in your thinking right? If the firing pin breaks from bending before the body, then won't almost every gun hold the same amount of bands? if the pin breaks from bending then it's going to do that with the same amount of bands on every gun meaning the only thing that matters is the distance per band because every gun can hold the same number of bands. The pin on the DD-27 will break from bending long before the barrel even comes close. That would mean in theory that using the same type of firing pin we should be able to hold the exact same amount of bands.

4. Greys only suck on guns like the TR with no extended barrel. With the DD-27's long barrel greys get really good ranges, power, and accuracy.

Whaleman (author)dsman1952762010-01-09
1. Not entirely sure what you mean.

2. I did not say that the body would break from bending. The body breaks from the impact of the pin hitting it. Not every gun can take the same amount of bands and still be able to fire. It isn't the pin that breaks; it's the body of the gun.

3. Use oodammo if you have a short barreled gun. Add a longer barrel if you want to use grey rods with an Untangle or TR. In my experience, however, I have never seen a grey rod shoot better than a red rod or oodammo. 
DJ Radio (author)dsman1952762010-01-09

The TR shoots VERY hard with 2 bands.  This is even better, and it keeps the pin from breaking.

knextard (author)2008-07-12

OOPS what are hinges O.O

dsman195276 (author)knextard2008-07-12

there on the trigger system. if you don't have one then you can use the gun like a block trigger, sorry :-)

DrWeird117 (author)dsman1952762008-10-22

Now, I'm VERY bored. Should I build this, or the "TRUELY semi-auto"?

i don't know. both are pretty good, but i would say this. Although this doesn't have the looks, i searched knex rifle and sorted it by rating, and it was the first actual rifle

NYPA (author)blueberrypieisgood2009-07-24

not a rifle! does it have the bullet spin out of the barrel? no!? NO RIFLE THEN!

DJ Radio (author)NYPA2009-07-25

there isnt a knex gun in the world that can do that. forget about the real definition of a rifle.

About This Instructable




Bio: Just your average K'Nexer/Programer/Nintendo DS fanatic. Any questions you would like to ask about any of the above? Send me a PM ... More »
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