| Author |
Message
|
| clemsonguy1125 |
 Posted: 03/05/2010 20:04 PM Post subject: 1/4 Brakeline Barrel and Copper Pellet gun |
 |
|
Major General
Joined: 21 Jul 2009
Posts: 1486
1475.73 Spud Bux
|
| I just bought a piece of 1/4 brake line as the barrel for my pellet gun. My problem is the 4.5 mm pellet/bb fits loosely and has a gap, will putting wadding behind the pellet yield decent power compared to a perfect sized barrel. Also at a 100psi is it possible to get decent power from a pellet in a piece of 1/2 inch copper pipe as the chamber. It will be a coax. I plan to use a blowgun to pilot it. Ill probably cast a epoxy piston. |
|
| Back to top |
|
 |
|
|
|
| Gun Freak |
| Posted: 03/05/2010 20:31 PM Post subject: |
|
|
The Anti Hybrid
Joined: 25 Jan 2010
Posts: 4210
333.21 Spud Bux
|
| A .5 in. chamber and a .25 in. barrel on a co ax doesnt leave a big volume unless its really long. Also the wadding will definately help, you just need a ramrod. |
|
| Back to top |
|
|
| Hubb |
| Posted: 03/05/2010 20:36 PM Post subject: |
|
|
Major General
Joined: 28 May 2007
Posts: 2410
701.43 Spud Bux
|
| Gun Freak wrote: | | A .5 in. chamber and a .25 in. barrel on a co ax doesnt leave a big volume unless its really long. Also the wadding will definately help, you just need a ramrod. | If you are going with such a small chamber volume, and are doing it in copper pipe, why are you limiting the pressure to only 100psi? GGDT will make a prediction for you, but I can just about bet that you will not be satisfied. |
|
| Back to top |
|
|
| MrCrowley |
| Posted: 03/05/2010 20:47 PM Post subject: |
|
|
Kaleun
Joined: 23 Jun 2006
Posts: 8999
9195.37 Spud Bux
|
| From experience, you wont be happy with the power. I wouldn't want to be shot by a BB at 100PSI from such a cannon, but power will seem pretty pathetic. You'll still shoot through a soda can though. |
|
| Back to top |
|
|
| clemsonguy1125 |
| Posted: 03/05/2010 20:55 PM Post subject: |
|
|
Major General
Joined: 21 Jul 2009
Posts: 1486
1475.73 Spud Bux
|
| MrCrowley wrote: | | From experience, you wont be happy with the power. I wouldn't want to be shot by a BB at 100PSI from such a cannon, but power will seem pretty pathetic. You'll still shoot through a soda can though. |
Would a larger chamber volume increase power for a cannon on a coax this size.
And to Hubb
I am limited to 100 psi because I only have a cheap bike pump |
|
| Back to top |
|
|
| Hubb |
| Posted: 03/05/2010 21:54 PM Post subject: |
|
|
Major General
Joined: 28 May 2007
Posts: 2410
701.43 Spud Bux
|
A larger chamber will, in fact, increase the power, as long as the barrel is of the right size. As far as your bike pump, consider an upgrade.  |
|
| Back to top |
|
|
| Crna Legija |
| Posted: 03/05/2010 22:48 PM Post subject: |
|
|
shots shots shots
Joined: 20 Jul 2008
Posts: 1915
1664.80 Spud Bux
|
| make the chamber a bit smaller and get a shock pump, at 300 psi you want be disappointed at the power. make sure if you ram wad and ammo down that you stop it going into the chamber |
|
| Back to top |
|
|
| jackssmirkingrevenge |
| Posted: 03/06/2010 1:43 AM Post subject: |
|
|
aspiring machinist
Joined: 15 Mar 2007
Posts: 18061
32519.23 Spud Bux
|
| Hubb wrote: | | A larger chamber will, in fact, increase the power, as long as the barrel is of the right size. As far as your bike pump, consider an upgrade. |
Couldn't agree more, the smaller you go with calibre the more you need to up the pressure to keep the power up. Remember that to have the same power potential as a 1/2" barrel at 100 psi, a 1/4" barrel needs 400 psi.
A shock pump is a cheap and useful source of 300-400 psi for a small chamber, and if you have access to proper epoxy making a small piston cannon should be no problem at all. You could very easily take this design and make it longer. |
|
| Back to top |
|
|
| clemsonguy1125 |
| Posted: 03/06/2010 13:46 PM Post subject: |
|
|
Major General
Joined: 21 Jul 2009
Posts: 1486
1475.73 Spud Bux
|
| jackssmirkingrevenge wrote: | | Hubb wrote: | | A larger chamber will, in fact, increase the power, as long as the barrel is of the right size. As far as your bike pump, consider an upgrade. |
Couldn't agree more, the smaller you go with calibre the more you need to up the pressure to keep the power up. Remember that to have the same power potential as a 1/2" barrel at 100 psi, a 1/4" barrel needs 400 psi.
A shock pump is a cheap and useful source of 300-400 psi for a small chamber, and if you have access to proper epoxy making a small piston cannon should be no problem at all. You could very easily take this design and make it longer. |
I might see about upgrading to a shock pump and I my switch to a 1 inch chamber and a tee valve http://www.spudfiles.com/forums/high-pressure-steel-piston-valved-rifl e-in-progress-t19694.html like this, because I dont want to deal with copper and I can screw all these parts together |
|
| Back to top |
|
|
|
|
