Login    Register
User Information
We are a free and open
community, all are welcome.
Click here to Register
Who is online

In total there are 59 users online :: 2 registered, 1 hidden and 56 guests

Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot] based on users active over the past 5 minutes

The Team
Global Moderators
global_moderators.png CS

Bolt action coaxial?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
  • Author

Unread postAuthor: jackssmirkingrevenge » Fri Jan 23, 2009 12:57 am

Have a look at this one I had built, allows you the potential for breech loading as well as upping the performance significantly on account of the zero pilot volume.
  • 0

User avatar
Donating Member
Donating Member
Posts: 24976
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 120

Unread postAuthor: MakerOfToys » Fri Jan 23, 2009 1:14 am

First things first: Hi, everyone. . . been lurking for a few weeks.

To business:
the piston/barrel seal in this design is a ROYAL pain. . . .

6 years ago, I built an all-metal (aluminum and steel) artillery-loading version of this idea, firing soda cans/tennis balls. (150PSI max, 10ft BBL, 8 rnds/minute sustained.)

it'll kill a cinder block in one hit at 50 yards/70psi; we're talking total demolition here. I sound like a hyena anytime I get it out.
The sound is fantastic, and the visual effect of the soda can bursting is really nice.

I'll have to dig to find photos (that was about 3 computers ago. . .)

there are refinements I'd like to make to simplify loading, etc-- time, always time.

were I you, I'd go get a $20 caliper (at least) from the local harbor freight, and look at what Parker, et. al. have to say about the "crush" required for various pressures vs o-ring section diameter before I got started. I know I scrapped a couple of parts before I did. . .
  • 0

Posts: 6
Joined: Fri Jan 23, 2009 12:48 am
Reputation: 0

Unread postAuthor: sputnick » Fri Jan 23, 2009 1:48 pm

JSR, Did your gun end up looking (internally) like the drawing, because you're right, there is technically no pilot volume, but the air flow looks very restricted, I also don't see how you would potentially breach load it, unless the whole piston device moved backwards, and then you could only load pre-pressurization.

I do not really see how you would breach load that while keeping the parameters of the original gun, it would need much modification, although it is worth looking into...

By the way, how much pressure can a syringe hold safely?
  • 0


Add me on MSN to chat about whatever!
User avatar
Lieutenant Colonel
Lieutenant Colonel
Posts: 498
Joined: Sun Dec 14, 2008 3:53 pm
Location: Ontario Canada
Reputation: 0

Unread postAuthor: POLAND_SPUD » Fri Jan 23, 2009 4:47 pm

that 1/2 inch pvc is actually 3/4 inch? and 3/4 inch pvc is 1"??
it's the same with malleable iron pipes... it is the so called nominal size..
  • 0

Children are the future

unless we stop them now
User avatar
Chief of Staff
Chief of Staff
Posts: 5405
Joined: Sat Oct 13, 2007 4:43 pm
Country: Israel (il)
Reputation: 11


Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot]

Reputation System ©'