"Snowy Savanna" -6mm bullpup-bolt-action (first po
Posted: 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]
(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]
what pressures are you filling it to, and what's the performance like?