New Piston Cannon....Near Explosive Decompression

[jmadden91]

Mate this thing is beautiful. Its in the wrong spot though, a mod needs to shift this over to the showcase

Beautifully done velocity

[Carlman]

Come onmate get some pics actually in the thread, i came to this thread a while back and couldnt be bothered looking at it because of the lack of visual aids...

But anyway very nice work mate!

[Gaderelguitarist]

Absolutely stunning work!
The multitude of hex bolts does indeed give it a military look.

Oh the things I would do for access to a machine shop...

[jackssmirkingrevenge]

Beautifully made, though some illustration of its performance would be appreciated

Also, why operating at such a relatively low pressure?

edit: hadn't seen the damage pics, use the image tags

[jimmy101]

Damn that is a sweet build. For a first gun it's off-scale. Overall I would put it easily in the top 1% of the thousands of "spudguns" I've seen posted.

Really should rename it though, "Hungus" it ain't. It's beautifully executed, looks well balanced and a heck of a lot more portable and manageable than 99% of guns of similar size, most of which probably don't perform nearly as well.

Personally, I would go with something like "ElaGun" (as in elegant).

Make a thread in the pneumatic finished gun forum with pictures. This gun definitely needs to be on the web in a few different places so that it's description and photos will survive "web rot".

EDIT:

MOVIES PLEASE!!!

Chrono data would be sweet. A shooting chrony is about $70, or you can build your own for a couple bucks if you have a laptop or old PC that you can get to the shooting site. There are several people on this forum that can help with a homebrew chrono if you need it.

[Moonbogg]

A couple boxes of SHCSs and a counterbore. Good stuff.

USGF

I can't tell if you were being sarcastic or not. Is it good or bad? Or, for a quick esape, it could be neither.

[velocity3x]

Jack,
I'm still operating it a "Relative low pressure" because the gun was just completed just over a week ago. I haven't had much time with it to find it's upper limits. The pressure gauge on the gun tops at 160psi max and until I get into town to buy another.....I won't exceed it's max. I did some testing this morning at 160psi in prep for a video maybe next weekend. As for the performance I have nothing yet except my observations. At 160 psi, the ball can't be seen in flight. At a distance of 100', the ball "drills" a hole completely through the 16" thick hay bale backstop and some balls land 100 yards beyond. At 160psi and the wheel brakes locked, the recoil is extremely brutal on the 100+ lb gun. It's definitely not a shoot from the shoulder or hip kind of gun. In future days I plan to increase testing pressure to a max of 400psi.

Jimmy,
Thanks for the good words. A crono is on my shopping list for next week.

[jackssmirkingrevenge]

In future days I plan to increase testing pressure to a max of 400psi

Looking forward to that

Performance is probably already overkill but given the disparity between chamber and barrel volume, you could easily add a foot of barrel length for even higher velocity. It would also help with noise abatement.

One small curiosity, do you find that venting the pilot downwards spoils your aim, or does it counter muzzle rise in the way a compensator does?

It would also be interesting to see some alternative ammunition in action, a sabot and fistfull of BBs would make one heck of a shotgun

[USGF]

A couple boxes of SHCSs and a counterbore. Good stuff.

USGF

I can't tell if you were being sarcastic or not. Is it good or bad? Or, for a quick esape, it could be neither.

Moon, we are planning on building some intense stuff too. Note that this build would be very expensive even with a machine shop. Left over billet is not bad but if you gotta buy it...... Hats off to this builder. VERY nice.

Oh BTW, I know you know but SHCS are socket head cap screws for those who don't.

http://www.palmerbolt.com/catalog.asp?p ... prevnext=1

Counterbores are the tools used to cut the sunken seats for those screws.

USGF

[starman]

Wow! Not much to say that hasn't already been stated. I love the barrel support rails and overall machined look and execution. The WWII theme works very well and the dolly mount is a sweet touch.

Beautiful work velocity! You have placed yourself squarely in the upper echelons of cannon building.

[Moonbogg]

A couple boxes of SHCSs and a counterbore. Good stuff.

USGF

I can't tell if you were being sarcastic or not. Is it good or bad? Or, for a quick esape, it could be neither.

Moon, we are planning on building some intense stuff too. Note that this build would be very expensive even with a machine shop. Left over billet is not bad but if you gotta buy it...... Hats off to this builder. VERY nice.

USGF

I always thought c'bores were pretty cheap if you're already drilling a hole anyways. Same setup and usually with one tool from what i've seen. Its clear this builder wasn't going the economical route anyways. This is something that will last him forever and be worth every penny.

Yes, this poster's cannon is incredibly beautiful. Hats off for sure. One thing I find very sweet looking is the scuba tank mounted underneath. It looks like a high end pneumatic air rifle (oh wait, it is!). Very cool.
velocity3x, if you wanted you could also look into 1 1/2" SCH10 6061-T6 pipe. It could easily mount via bushings. Either way, I love the style of this design and I bet its crazy powerful. It looks like it would be so much fun to aim around your yard on that pivoting mount you have (very nice BTW) and just shoot all day at random fun stuff. Awesome build and I hope you make others.

[velocity3x]

One small curiosity, do you find that venting the pilot downwards spoils your aim, or does it counter muzzle rise in the way a compensator does?

Jack,
I aimed the pilot valve down to protect my eyes while firing. The valve is 3/4" and the pilot chamber contains only 6 cubic inches of pilot air. The discharge from the pilot valve is extremely insignificant. The gun is balanced in the vertical pivot about 1 pound heavier at the muzzle end to counter any flip. As a result, the gun stays flat and on target while firing. All the recoil is directed straight back along the longitudanial axis of the barrel resulting in zero muzzle flip. However, the recoil is still quite strong. With the wheel brakes set, at 160psi the recoil slides the 110+lbs cannon and dolly backward a couple inches on the concrete floor.

[dewey-1]

Velocity3x;

Thanks for posting pictures rather than the links!

Everyone here will enjoy your beautiful workmanship more!

Much easier to to do than looking up on a separate service.

Looking forward to more projects from you!

[velocity3x]

The WWII theme works very well and the dolly mount is a sweet touch.

Thanks.
It would be impossible to fire without a mount. I also built another mount so I could load the gun (with minimal effort) onto my pickup truck and haul the cannon and CO2 tanks out to the desert for some long range tests.

<img src="http://i145.photobucket.com/albums/r240 ... 1244479624">

The vertical pivot mount is attached to an aluminum flange containing 2 front wheel bearings back to back (1994 chevy 2500hd Hey...on a farm you use what ya got). The aluminum flange bolts to a mating flange on the dolly and separates from the dolly flange with 4 bolts. The truck mount has the same mating flange as the dolly. It's "L" shape and plugs into the receiver hitch of the truck. The cannon can be moved from the dolly to the truck in just a few minutes.

[Daltonultra]

Incredible...I'm speechless.
Almost as speechless that such an incredible cannon should lack the perfect trigger...
I use a 1/2 QEV as a firing valve for my blow-dart gun, and I think it would be the perfect pilot for your monster:

http://www.fastenal.com/web/products/de ... 206&ucst=t

You also need a trigger valve to pilot that(recursion, sweet recursion!)
And this little sucker provides that service for me:

http://www.mcmaster.com/#6790t42/=29jtri

(look for yellow highlighted entry)