Silent System( now broken by dieseling!)

[jackssmirkingrevenge]

and the idea of a silenced sawn off .... lol

Not as lol as you think, tunnel rats in Vietnam used the AAI 12 gauge "telecartridge" which works on the same principle but using a captive diaphragm rather than a piston in sawn off double barrel shotguns.

[Brian the brain]

nowwww just make some shotgun ammo and it really will be a sawn off : )

That did not make sense..

I have fired bb's out of this thing...
The gun itself is not new.
I made version 1 somewhere in 2006 I believe..

Got new arrow material today...
Time to build the new barrel...

[jackssmirkingrevenge]

Why not make a revolving magazine and try to replicate the ultimate sawn off silent shotgun

[Major Collins]

"Brian the brain"
That did not make sense..

lol how so...? if i can recall ... well today modern day sawn off shotguns dont shoot arrows... they shoot shotgun shells... lol

[al-xg]

lol how so...?

AAI 12 gauge "telecartridge"

This is something I also wanted to try out for ages, but with a longer barrel, and some sort of buffer spring to stop the piston from getting wedged.

To be able to remove arrows from the target (unharmed) tips like this (or the middle black one on this pic) make the process much easier, but then they will also tend to fly right through thinner targets.

[psycix]

You could reduce the impact of the sabot by using an air-bumper.

[roboman]

How so...? If I can recall...well, today modern day sawn-off shotguns don't shoot arrows...they shoot shotgun shells...

I don't think shotguns shoot shotgun shells...I seem to recall them shooting shot or other ammunition, such as slugs. I believe this was only called a "sawn off shotgun" due to the styling of the gun.

[Brian the brain]

Wait wait wait...

This is a sawed-off shotgun...well...a pneumatic version...wich I modified to launch arrows.
What didn't make sense to me is the suggestion to remove my modification to turn it back into what it was...????

The first version, with wich I shot " shot" regularly, dates back to januari 2006.

First sawed-off
version januari 30th 2006:


version two

\break barrel version:

Mark III with it's big bolt action repeater brother:


So suggesting to do that to turn it into a real sawed-off seems a little weird...since I have done nothing else for almost 4 years with it..

There is basically nothing I haven't tried when it comes to pneumatics...

Thank you for not disappointing me Psy... but you have given away the surprise..I was planning on finishing it tonight...I should have known your gears would start turning the second you saw the idea..

I think, with a rubber sabot, only a small section is needed to slow the sabot down to acceptable speeds for a metal barrel.

The idea is not new, but still a SF first..
I never got around to it...although I had suggested it some time ago..
It's pretty simple and not really a great innovation, just something fun to try.
As theories tend to get a lot of pages without actual result, I thought I'd just build it.
Hope you like it.
I'd like to see what you guys make of it.

After 50.000 years of development...we're back to sharpening arrowheads..

[psycix]

Rubber might deform and leak air from the air bumper. Since the air bumper already takes the impact, this means that you could use something else, like a lathed piece of plastic.

Thank you for not disappointing me Psy... but you have given away the surprise..I was planning on finishing it tonight...I should have known your gears would start turning the second you saw the idea..

We've got the same kind of gearing.
Great minds think alike eh?

[JDP12]

Air bumper is what I was planning to use in a new design of mine. From the calculations I've done it will work very well for both my purpose and yours.

[Brian the brain]

The arrow closes off the front, Psy..
So you don't need the complex shape..
Just any piston will face one big airbumper the way you've drawn it..

It needs ventholes, but placed strategicly.
Not too far back, because of the need to trap the gas, not too far forward either.The section in between is your airbumper.

We could also leave out the holes and use the frontal area to spit out the arrow even faster.Or perhaps use it to diesel..

In that case the piston needs to seal 100%, an o-ring should be around the arrow and the back of the arrow should be exposed to the pressure.
I.o.w. not seal against the piston..

But that would probably make it less silent.( esp. dieseling).a nice experiment, yes, but not the goal for now.
I still like the idea of a rubber, or perhaps cork piston.

[jhalek90]

Btw.... dont do this with pvc.... lol duh?
http://www.spudfiles.com/forums/viewtop ... tml#270268
mine blew up... but strangely enough.... not where the piston impacted.....???
any ideas?

[jackssmirkingrevenge]

any ideas?

A lightweight piston and a decent bumper is a good start, have a look at nailgun design:



Some sort of tight breech/detent that would prevent your projectile moving before a certain pressure is reached would also allow the air in the piston to act as a better cushion, as well as increasing power.

[origin unknown]

Really nice work, man. I always enjoy your craftsmanship on all your creations. BTW, what kind of wood did you use to work with? Pine with a dark colored stain?

[Brian the brain]

Well origin unknown..
This topic wasn't so much about the cannon.
I showcased it earlier.

I just used it to implement the silent system.

It's some sort of hardwood.Not sure wich..I salvaged the piece.