SpudFiles

I am very interested to know what are the longest ranges achieved, (and with what ammo) and the pressures involved in achieving these ranges. I am just starting out and would like to know what are your results that have been achieved repeatedly. Also, share if the cannon is untethered or connected to a compressor while firing.

My goal for a higher power pneumatic is 1 mile with a golf ball type projectile. I live in the desert, and so this could be accomplished safely as far as friendly fire goes.

Has anyone compared the possible differences in smoothly tapered reducers vs step down reducers?

Also, has anyone tried greasing/lubing the barrel for a better seal and less drag? Any improvement with it, or just a spray of lube at the muzzle end?

I'm up to 1/4mi or so using 2" caulking tubes with a bit of concrete loading in the tips. I think some here exagerate a bit on ranges achieved. I know mine at this point is limited by the unavailability of a larger ball valve, or my procrastination of getting around to building a coaxial style valve.

My experience is to forget the golf balls. They haven't enough mass to overcome wind resistance.

The caulking tubes are heavier, seal in a 2" rigid electrical conduit, more accurate than any spherical object I've tried, and best of all, are one mans trash, my free ammo! I get them by the boxful from a local windshield installer. Of, and did I mention they are metallic?

Also, longer barrels are necessary with the heavier ammo. It gives the projectile more time to accelerate before losing back pressure.

E

A mile is almost certainly impossible using golfballs.
I'd look into a (saboted) steel dart with a design similar to an arrow. Most hardware stores cary steel rods in appropreit diameters. (I'd check the welding section)

what state do you live in?
my DOBA launcher could launch a golfball about a mile, but it is too expensive for most people to make.

DOBA launcher?
Could you give me a link? Im curious.

Not yet fully built, bu tI can give you ggdt specs.

okay then......

Ok that would be nice:D

Waiting for the specs aswell.But 1mile 1600meters is very far but not impossible,instead of making a steel dart why not just shoot an arrow?With a sabot.It might be a bit light but it can be weighted.

Hmm, now i want to build a semi auto arrow launcher.
Same principal as a semi-auto gb gun but with a arrow magazine.

http://www.thespudmall.com/files/supersonicgolfball.gdt
Remember, ggdt does not take into account lift from the dimples or backspin.

http://www.thespudmall.com/files/leadball.gdt
with lead ball

With my cannon a 3 inch chamber by 61 inches, 1.5 inch barrel by 108 inches firing at about 125 psi connected and not connected to my air compressor and for a valve I used a ball valve, I got about 2000 feet.

With a 4inch barrel you could shoot lawn darts and those are already weighted and should go very far.

Thanks for the responses!

I am in NV, with alot of room around me for ranging. (We own 40 acres, with 1/4 mile on each border, and alot of open range around us) I figured the golf balls were plentiful, and had a fair amount of mass. I also wanted to have some hope of tracking them to verify ranges achieved. (My wife and I can work together on this with radios - she can shoot and I'll duck!) If they are not suitable, then I can find something that has the right amount of mass and good aerodynamic properties for stabilty and range. Has anyone tried drilling the golf balls, and adding melted solder or wax for ballast?

What is a DOBA launcher?

I have multiple plans in mind for various uses. This large cannon would be connected to a compressor, but others will be portable. I am also very interested in using steel for higher pressures, and can weld mild and stainless.

Has anyone tried building a semi or full auto with a buffer chamber for the air? This would utilize a fairly large air chamber and pressure regulator, and be connected to a compressor through a regular small air hose (coil type hose even). As the air chamber runs low on air pressure, then the compressor would refill the chamber, but it would not have to supply all of the air for barrel pressures. I will try this idea this Fall with a regular 1/4" air line run off of an Emglo air nailer compressor, set at ~110 psi.

It sounds like quite a few people on this board have also been into paint ball guns. I believe those operate at a higher pressure (am I right?). Any luck using those high pressure tanks (filled at a high pressure of course) with a launcher? How about diving tanks, or even CO2 welding tanks for pressure. This would be with a pressure regulator of course and welded steel launchers.

How about shaved tennis balls (or ping pong, or hand balls, or racket balls) filled with water and frozen, for the larger higher pressure launchers?

For arrows and high pressure/high power toys - have you seen this? http://www.swivelmachine.com/html/stealth.htm
The archery model was used in the (bad) movie 'Hard Target'.

Benstern - great avatar!
Anon - nice job on the range!
Haymaker - nice to see someone else has tried using RMC for launcher material! Thanks for the ammo feedback also.

I don't say impossible without a good reason... I played around with the GGDT until I was getting muzzle velocities in the vicinity of mach 13, and I STILL wasn't getting a mile.

...Ok, fine...
The .1s interval was probably screwing with things.
Lemme plug the values into joanna's range estimator...

...and nope, even mach 380 won't get me the range I need.

The "DOBA" launcher is simply a large, high pressure pneumatic launcher that benstern is planning on making. He hasn't decided apon a design yet, but still likes to shout out preformance claims.
Yeah, I'm being a bit harsh... gives benstern another reason to build it, I figure.

(Joanna's ranger seems to be indicating that a standard arrow might get the range you want (I don't really know the drag coefficient of an arrow, so salt that heavily). I suggest saboting the thing and using an overly large valve/chamber system with a long barrel. (maybe a large, 2" barreled co-axial with a 1.25" barrel insert. See "interchangabel barrels on a co-axial))