Author Topic: Barackuda (gun)  (Read 5756 times)

Offline TheDunc

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Barackuda (gun)
« on: February 19, 2016, 06:04:24 pm »
Posted on 'ibles I figured I should contribute here too. This here's what I call the Barackuda, a combination of barracuda and Barack (Obama) because of no particular reason.



For those not too familiar with K'nex gun building, a brief introduction: Most K'nex guns work by using a rod, what we call the firing pin, driven by a rubber band to hit the bullet and propel it. From pretty early on we learned that the bullet would fly farther by having the firing pin accelerate as much as possible before hitting it. This involves two basic concepts: make the space between the trigger and the back of the gun as minimal as possible and have the bullet sit as close to the end of the firing pin's path as possible. So we made guns that fired a single bullet pretty hard pretty easily, but these required you to manually place a new bullet in the barrel each time, like an old musket. Now, a gun with the ability to fire more than one shot without needing to manually feed in a bullet each time is called a repeater. Most of the first K'nex repeaters used a direct feeding magazine. A box pushed/dropped the bullets straight into the barrel of the gun. It was simple but inefficient. K'nex rods tend to snag when dragged across each other. This snagging caused the rounds to lose a lot of velocity while leaving the barrel, meaning that repeaters generally had a lot less range than single shot guns. So long ago I noticed a concept called bolt action. It involved using a handle at the back end of the barrel to both pull back the firing pin and to push a separate pin into the magazine to push a single bullet into the barrel. However, it was only a novelty and didn't really perform that great, plus the example I saw used a magazine that fed from the top of the gun. I envisioned a weapon that used this concept to maximize firing pin travel distance and fed from a magazine on the bottom of the weapon. By pushing a single round into the barrel and isolating it from the magazine, a repeater could have roughly the range of a single shot weapon. Anyway, long story short is that after I presented my idea, other K'nexers took to it and built their own, some that ended up being very well-received guns, but I never was able to produce one that I was satisfied with until recently.


So now here we are. This is my latest version. The first one came about when I was actually fiddling around with the magazine design before I came up with a weapon to use it. The purple cylinder is the magazine. It's an odd design, called a rotary magazine. It stores the bullets on the outside of gears, rotating to push the bullets against a ramp that feeds them into the gun. This is removable and can be loaded with bullets before hand. It stores up to 12 yellow rods, though 2 of them can be shaken out, the other 10 remain secured. It's a relatively compact design given that a normal, straight magazine that could hold 10 rounds would end up extending to about the same length as the handle. The rest of the gun was designed to be compact as well. It's hard to see because I ended up taking the picture head on with it, but the bolt handle is the metallic 3 slot connectors you see with the alternating orange and red rods sticking out at the top in the middle section. You pull this back to set the firing pin, the trigger sets and holds it back, then you push the handle back forward which pushes another pin into a gap in the magazine where a bullet is sitting, and then forces the bullet up a ramp that places and holds it inside the barrel. I'm about finished with it and then perhaps I'll post it, but I just need to tweak the trigger to be more reliable.

Offline Lucas The Boss

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Re: Barackuda (gun)
« Reply #1 on: February 20, 2016, 12:53:57 am »
This is really cool. I might give a try at a rotary mag soon. Are you going to give a shot at me and blue mullets repeating sling shot concept? We would really like to see it used more.

Offline Northern Fields

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Re: Barackuda (gun)
« Reply #2 on: February 20, 2016, 11:55:41 am »
Thats so cool. I've built a few guns but never really anything serious. I like the mag design and to have all you've said going on inside it it must be really compact!

Offline Linkin_J_Knex

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Re: Barackuda (gun)
« Reply #3 on: February 20, 2016, 01:32:32 pm »
cool magazine! I like the overall looks of the gun, except the connection of the stock to the back end of the gun. It looks kind of flimsy. The rest of the gun looks great!
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Offline TheDunc

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Re: Barackuda (gun)
« Reply #4 on: February 22, 2016, 06:52:36 pm »
This is really cool. I might give a try at a rotary mag soon. Are you going to give a shot at me and blue mullets repeating sling shot concept? We would really like to see it used more.
That depends, what slingshot concept? I'd definitely like to work on one eventually. Good luck on a rotary mag. I'd always thought a Johnson rifle with a true rotary magazine would be awesome. Reloading it would be really tricky, though.

cool magazine! I like the overall looks of the gun, except the connection of the stock to the back end of the gun. It looks kind of flimsy. The rest of the gun looks great!
Thanks, and it's surprisingly sturdy. I knew it'd be a problem with trying to keep the gun compact that the stock connections would be limited, but what is there works rather well. And it's hard to see in the photo, but I reinforced the connection at the back of the gun with a couple more purple connectors around the blue rods on the outside, so it's not going to snap off so easily.

Offline Linkin_J_Knex

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Re: Barackuda (gun)
« Reply #5 on: February 22, 2016, 06:56:50 pm »
oh okay :) I'm slightly confused by the gun too, is it a simple pin gun but with that epic mag?


EDIT: Oh sorry i re-read it and i understand :)
« Last Edit: February 22, 2016, 06:58:41 pm by Linkin_J_Knex »
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Offline TheDunc

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Re: Barackuda (gun)
« Reply #6 on: February 22, 2016, 07:03:25 pm »
I'll get more pictures later so it's a little more understandable.

Offline TheDunc

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Re: Barackuda (gun)
« Reply #7 on: March 15, 2016, 08:28:47 pm »
Updated the gun and I'm just about ready to post it. I'll end up getting another video for this version and posting it here.

Offline Linkin_J_Knex

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Re: Barackuda (gun)
« Reply #8 on: March 16, 2016, 05:00:44 pm »
Sounds great!  ;)
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Offline TheDunc

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Re: Barackuda (gun)
« Reply #9 on: March 21, 2016, 02:46:17 pm »



Got a video. It assumes you watched the first video I posted and goes over the updates I made, but you'll still be able to understand the gist of the weapon from just this video. I just want to try improving the feed ramp one more time then I'll get instructions.

Offline Linkin_J_Knex

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Re: Barackuda (gun)
« Reply #10 on: March 21, 2016, 05:28:48 pm »
looks great! :D
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