u2-piston rifle

[spud yeti]

But the paint job reminds me of a paintjob Jack showed me once, I can't find the link back to it. The camo-tigerstriped pistol.

I remember that. I agree this does look similar, but black, not red/orange.

[joannaardway]

...I could possibly critisize is the pilot volume, which is quite big due to your pipe...

I would have said the pilot volume was fine. The dead volume however is a little big.

I mirror everyone else's comments - fabulous cannon.

[mega_swordman]

A very nice and well constructed gun. It looks fantastic, keep up the good work!

[locksmith]

Very nice build

[experament-u2]

Oh, a question ( 8) ): What pressure do you like running it at?

i run it at 100psi

But the paint job reminds me of a paintjob Jack showed me once, I can't find the link back to it. The camo-tigerstriped pistol.

thats were i got the idea to try it

Wow, very nice. It looks like your barrel port is a little too big for you piston. How did you get it to work?

i have a slightly smaller bit of pipe glue inside my barrel thats what the piston seals againced

[jackssmirkingrevenge]

Or should you rather say logic is spreading
At last the good word is becoming known to all...*sigh*...

I think it's an attitude thing - many people are content with just coming up with something that works. Personally, I would rather make the slight extra design and construction effort to make something that works as well as it can. Air is not the most efficient medium for propelling stuff at high velocity, compared to solid propellants, so it's my contention that waste should be kept to a minimum.

[Pyro Ninja]

finally got it posted.....great to see the final product ...looks awesome

[joannaardway]

I think it's an attitude thing - many people are content with just coming up with something that works. Personally, I would rather make the slight extra design and construction effort to make something that works as well as it can.

I wholeheartedly agree - just a few small changes can make that difference between a good cannon and a great cannon.
If you're going to shell out the cash, it's worth those few extra coins, and bit of extra effort to make it it's absolute best.

[bassmaster1228]

that is an awsome gun... i reely like it

[joannaardway]

@JSR: Actually, just minutes after my last post, I found this page, which gives a rough idea of the efficency of firearms cartridges:

http://www.loadammo.com/whatisballistics.htm

Taking the figure of 29% efficency (for the Browning machine gun), it's easily possible to surpass ~30% efficency with compressed air.

So, it seems air can be on a par with solid propellants for energy efficency. Not that it's good on volume efficency.

[noob of noobs]

That's simply amazing! How did you get the cap to fit on the tee in your piston valve? Is that possible with PVC? Also, isn't the ball valve hard to turn with one finger on such little leverage?
Anyway, that's some truly top notch work there. Can't wait to see the damage pics!

[MrCrowley]

First of all that is PVC, just painted black.
Second Im guessing he did what i did with my golfball gun piston valve and sleeve the isnide of the tee with 20mm PVC pipe and just bolt a 20mm endcap on it.

[jackssmirkingrevenge]

So, it seems air can be on a par with solid propellants for energy efficency. Not that it's good on volume efficency.

That's the point I was trying to make, for practical purposes (ie at working pressures) volume for volume air lags woefully behind solid propellant, so short of having a ridiculously powerful compressor or ridiculously large chamber an barrel, one has to maximise efficiency in order to glean the most from a spudgun.

[noob of noobs]

Sorry, I thought it was iron One question though, does bolting things on provide an airtight seal? Do you have to seal it with epoxy or something?

[spud yeti]

Sorry, I thought it was iron One question though, does bolting things on provide an airtight seal? Do you have to seal it with epoxy or something?

You seal it with an O-ring, then the screws. By expoxying it in, what would be the point of screws

EDIT: other than safety purposes!

BTW, I agree with what you say entirely JSR.