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"Snowy Savanna" -6mm bullpup-bolt-action (first po

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"Snowy Savanna" -6mm bullpup-bolt-action (first po

Unread postAuthor: nature-boy » Thu Dec 09, 2010 10:56 am

Hey Guys!

(skip to SPECS, if you are only interested in the gun!)

Although this is my first post, I'm neither new to the hobby, nor to this great site.
I've been some kind of a constant "silent observer" over about 2 years or more, (with some breaks, i was visiting spudfiles almost daily), what I really enjoyed and never felt like joining the site, because I found all the information I was looking for.
...besides I must admit that I was also a bit afraid, that making an account, would lead into spending even more time here, as I already was, what could have some negative influence on other (rather irrelevant) aspects of life...

Since I'm from let's say somewhere in europe, english is not my mother tongue, but I'm doing my best.
(Actually, reading spudfiles has really improved my english, more than anything in school could ever has been... )

Long story short, I build a few guns and this is the first one, I felt like it was worth sharing it with you, although it's not totally finished.


I had a few basic points in mind, which I tried to achieve with this design:

1. the best performance/efficiency I can get out of it.
2. compactness or/and the possibility to be disassembeld
3. multishot capability
4. interchangeable barrels
5. magazin for 6mm steelballs but also the ability to load darts etc.


For point 1. I deicded to make a homemade pushbutton pilot for smallest pilot volume (and better flow than blowguns, etc) and a breech where
the projetile is just millimeters from the sealing-face of the piston

For point 2. I chose it to become a bullpup with a trigger design, where a long rod pushes the pilot. For easy piloting, I also took care of a
certain amount of leverage at the trigger and also at the second lever in th rear of the gun

For point 3. I got a soda-stream bottle, where I removed the checkvalve, as the main-chamber, that feeds into the firing chamber,
via a ballvalve to adjust flow.

But the biggest mess was to achieve point 4, because it really was a PITA to cut threads into thinwalled copper or aluminium pipes
(only things available for me). So I had to epox them together before cutting threads, what failed several times, but finally I got it to work fine.
That is also the reason why i looks a bit awkward at the breech (consisting of several pieces of pipe glued together...) and I got some
serious leaking problems after finishing it, at the breech and/or the valve. At first the leakage was almost ignorable, but increased with the time,
so I finally decided to "pour" (with the help of a thin brush) epoxy in to it, from both sides of the valve, and let it rinse out of the barrel.
That worked rather fine against leakage, but now the piston wasn't fitting anymore, so I sanded the housing of it, and made a new piston.

After building the Stock and trigger-mechanism, I recognized the chamber being far to big for multiple shots, but I couldn't cut it down anymore, so I just
put a hot glue-stick (with a screw at the end to avoid it choking flow) into it, to reduce the volume,
(which could always be pulled out for higher performance shots)

What was also veeery fiddly, was the mag. I always got it to feed multiple rounds, and couldn't solve that by adding whatever detent I tried.
The problem is that it is feeding into the outer-barrel which has a inner diameter of 8mm.
Finally I added a vertical bolt pushing up a single round everytime, that has to be reseted manually every time, but I am not very lucky with this solution.
Besides I still have to sand that part internally again, epoxy find its way also to this place, and the rounds have a very tight fit, but I can't just drill
into it in the current (not anymore changeable) position, hmmm...


...ah yes, you might also notice that the copper fittings are epoxed instead of soldered together, what may be of special interest for someone...



Of course I have an outer barrel for this inner barrel, that is screwed into the threaded copper piece in the barrel-mount, but I don't have it here, i will post pics of it later.

Currently I'm working on a mount for the (cheap) scope I have, that will still allow barrel-changing.

Furthermore I want to build a triggerguard, bipod and a supressor for it.


SPECS

-interchangeable 6mm barrel
-mainvalve: barrel-sealing, springloaded piston-valve in a copper T
-piston: hotglue with neoprene sealingface glued on to it
-pilot: homemade push-button out of a screw, a piece of rubber tube and alu-pipe in a 10mm soldering brass fitting
-prefered ammo: 6mm steelballs
-O-ring-sealed moving barrel breech
-two fill valves: schrader in the rear, and quick-connect with build-in-check-valve.[/b]
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Attachments
IMG_5970.JPG
note that the two bolts in the mag are missing in this picture
IMG_5974f.jpg
this is the reservoir chamber, not attached because I currently run out of ptfe...
IMG_5971.JPG
with barrel removed
snowy savanna 3.jpg
winter paint job
snowy savanna 2.jpg
winter shooting.jpg
some shooting in the snow, highspeed footage of the clay santa will come soon...:-)
Last edited by nature-boy on Tue Jan 18, 2011 7:30 am, edited 3 times in total.
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Unread postAuthor: Gaderelguitarist » Thu Dec 09, 2010 11:09 am

Welcom to Spudfiles! :)

And what a way to enter the forum. Very nice. You might want to put a couple clear coats on your grip. Pine won't show hand gunk very well. I always coat my grips in some way.

Kudos on the homemade pushbutton. And double kudos for working it into a trigger. This is a very great start, and I hope to see more from you.


Future improvements I can see? I realize the chamber must act as a horizontal foregrip, but maybe continue the wood theme elsewhere on the gun, perhaps between the chamber and the gun. This will act as a support, further stabilizing the structure, as well as make it look more whole.
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so many muchness
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Unread postAuthor: Zeus » Thu Dec 09, 2010 4:36 pm

You've done very well starting here, the stock is very nice though staining or coating it with something to protact it will help.

The soda stream bottles are getting popular now, if my funds weren't directed elsewhere I'd get one.

I'm looking forward to seeing what else you make.

And I know my post is almost the same as Gaderel's.
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/sarcasm, /hyperbole
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Unread postAuthor: nature-boy » Thu Dec 09, 2010 9:27 pm

Actually I had planned to coat it in some way, but I haven't decided yet.
Maybe I will paint it white, I really liked the look of the
white bullpup Vektor CR-21's in District 9...

And speaking of soda-stream bottles.. this is the first one of three, which I have laying around here, with no use... So you probably gonna see more of them in my next projects as well...
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Unread postAuthor: Gaderelguitarist » Thu Dec 09, 2010 9:56 pm

Maybe I will paint it white


Thats not a bad idea. I feel that you'll need to do something in black as well though, in keeping with the guns from the movie.
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Unread postAuthor: jackssmirkingrevenge » Fri Dec 10, 2010 1:40 am

nature-boy wrote:...ah yes, you might also notice that the copper fittings are epoxed instead of soldered together, what may be of special interest for someone...


Noted, good job ;) what pressures are you filling it to, and what's the performance like?
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Re: 6mm Bullpup-bolt-action (first post)

Unread postAuthor: jackssmirkingrevenge » Fri Dec 10, 2010 1:41 am

nature-boy wrote:...ah yes, you might also notice that the copper fittings are epoxed instead of soldered together, what may be of special interest for someone...


Noted, good job ;) what pressures are you filling it to, and what's the performance like?
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Re: 6mm Bullpup-bolt-action (first post)

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Unread postAuthor: nature-boy » Fri Dec 10, 2010 4:39 am

Currently I'm filling with either a bicycle floor pump, or small shock pump, what means pressure can be 40 bar max from the shock pump (this one), but I tested it only up to about 25, but for the reason I can only shot indoors currently, I am satisfied with about 8 bar most of the time.
I also got a fridge compressor, actually I got 4 of them, but 2 are broken , and one has a horrible low flow, although it is out of really large freezer
(anyone knows a reason why, or wheter this is fixable??? Someone from poland? :wink: )
The compressor I am using now puts out 40 bar easily, but I am still looking for a good, long, affordable pressure hose, can't find a hydraulik one with non-metrical threads here...

And the performance is good enough for me (don't have anything to compare). With a longer barrel I shot a short steel bolt trough my old (sheet metal) computer casing with 12 bar or so.
Will post pics of that, when I visit my parents again, where I can also shoot outdoors, they live in a very rural area, instead of where I live, in the middle of a city.
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Unread postAuthor: nature-boy » Sun Jan 09, 2011 7:05 pm

Had some time over Christmas at my parents, which I used for:
-building a detachable suppressor
-building a mount for a reddot/scope
-adding detachable handle to the breech

...aaand PAINT JOOOB!

How do you like it? At first I had it just flat white and black, as proposed before, but I didn't really liked it, so I spend an entire day deciding how to pimp the white stock up...
This is what I came up with!
(last three new pics in the first post)
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Unread postAuthor: Lockednloaded » Sun Jan 09, 2011 9:52 pm

it looked a little ghetto when you first posted it, but it still was a great first, but now that it got a little bit of a cosmetic upgrade it looks amazing. do you get multiple shots per fill?
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Unread postAuthor: Gaderelguitarist » Mon Jan 10, 2011 10:38 am

Fantastic job on the paint. I really like how you continued the theme on the bottle.

It looks like you added a barrel shroud. Any thoughts on making that into a functional silencer?

The only things I would add to this are a trigger guard and a continuation of the wooden grip theme, but thats just me. Darn artist's brain.
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Unread postAuthor: jackssmirkingrevenge » Mon Jan 10, 2011 12:16 pm

Gaderelguitarist wrote:Fantastic job on the paint. I really like how you continued the theme on the bottle.


hear hear, looks great!
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Unread postAuthor: nature-boy » Mon Jan 10, 2011 6:40 pm

Lockednloaded wrote:do you get multiple shots per fill?

I get about 5 acceptable hard shots, and after that about 6-9 shots, that are too weak for my taste. I would really like to add a regulator to the gun, but the one I got is made of plastic and i don't trust it over 20 bar (rated to 16).
If I find the time I will build one for high pressure, but I will need a lathe for the stepped piston I'm afraid...

@Gaderelguitarist:
The shroud actually already is a functional silencer.
It has one big chamber in the rear and 4 smaller ones in the front of it, separated with polymorph-discs.
The triggerguard is in work, it will be of aluminum...
And the wood thing is a good idea, but I dont know how to add it to the existing stock, without it looking just... "attached somewhere" if you know what I mean...

@all:
thank you for your compliments!
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Unread postAuthor: The_Guerilla_Guy » Sun Jan 16, 2011 7:09 am

Hi,
A very beautiful Gun indeed, especially the painting.
SInce I'm from Europe also, I have a question to you: Could you simply screw in the sodastream bottle? Because I have one that has a weird screw on it that I can't screw in a normal Fitting I think. The bottle is kinda old though, so I might just have to buy another one.

And second, I don't really understand the trigger mechanism, could you maybe post a diagram of it?
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Unread postAuthor: nature-boy » Sun Jan 16, 2011 9:20 am

Thanks for the kind words Guerrilla Guy!

The Soda bottles I got have inner (female) and outer (male) threads.
I removed the checkvalve out of the inner threads (what was not that easy...), these were metric fine threads.
The outer (male) was 3/4, so I could use it.
But I had to use a lot of ptfe tape, because the connection was more "loose" than normally.
What bottles have you got? There are several different types and the ones I got are also older ones, which are not anymore sold/refilled everywhere.
Would you mind posting pics of yours?

Here is a quick made diagram of the trigger mechanism.
The (red) rod is free to move in a tube (turquoise) which is fixed/glued to the chamber pipe. The orange dots mark the position of the joints.
Got it?
I know that posting pictures of the gun with the stock removed would clarify that a lot, but I dont have it here and the stock is already glued.
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trigger mech.jpg
trigger mech.jpg (35.48 KiB) Viewed 7134 times
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