What would you Guys build?

[jackssmirkingrevenge]

However, it asks for valve open time and dwell time. I assume the open time is how long the valve takes to open fully and the dwell is how long it stays open

Spot on.

[High-PSI]

So, I decided to make it a high performance cannon. It will look cool, but not scale. I am focussing on performance, period. Looks will come second. I will make a decent stock and trigger assembly for it this month. For now, I have bench tested the functional components. Here is the setup;

3 to 1 tank to barrel ratio
1/2 inch barrel (.60 caliber)
1 inch Granzow fast acting valve piloted by a 1/2 inch direct acting Granzow valve and an upgraded high power solenoid
3 foot aluminum barrel

This will obviously be an electrically actuated gun.

I have charged the tank to 600 psi and dry fired it. I also charged it to 500 psi and fired a 8 gram slug through two sheets of 1/16 inch aluminum diamond plate. The gun is very loud for a small bore.

Here are a couple videos of it.





Matt

[Gun Freak]

Nice work!

[jackssmirkingrevenge]

HPA FTW!

I would highly recommend a pressure switch and safety valve on your charging setup.

You should really think about semi-auto

[pneumaticcannons]

Bery nice
As jack said, this would make a nice semi auto platform

[High-PSI]

I agree with both (safetys and semi auto). I have a few ideas for a basic semi auto system. But, I have lots of hobbies and I do not shoot very often. So, that may not happen. Of course, I am really getting bit by the bug for this stuff. It would be easy to use the Scuba tank with a feed to this gun, add a magazine and have fun. But, this will have to do for now. Right now I have to finish this gun, build my compressor, and my big 2 inch cannon is in pieces being rebuilt. The steel parts are at the powder coater, and the aluminum parts are being sent off to be anodized. Once the anodizing is done, I will do some decorative machining through the anodizing.

Anyway, this gun will get the powder coat and anodizing treatment too. It will have a nice stock (still trying to decide between an all wood carved and stained stock or a techno looking welded steel arrangement). I also have a nice scope for it. Oh, I have a green lazer sight as well. But, that may go on the 2 inch cannon because that gun has too much kick for a scope.

Matt

[High-PSI]

I decided on a stock style.....

I picked up some 10 ply oak plywood today to double laminate into 1.5 inch thick panel. I will carve a radical stock out of that.

I have another question for you guys;

I have a 800 psi fluid filled guage for this gun. It is a large 2 inch face. If it was your gun, would you mount that large guage on the gun, or just have it on the compressor? There is no reason to have it on the gun, really. It would just look cool recessed into the stock.

Thoughts?

Matt

[High-PSI]

Here is the stock (so far). It consists of two layers of 10 ply oak laminate 3/4 inch plywood joined together. The barrel chanel was made by routing each panel separately then joining them together. The stock will be very lightly stained, then varnished. The tank will be powder coated black and the barrel will be anodized black. There will be various scope mounts, barrel brackets and the like that will be machined aluminum, anodized black. I have tested the system up to 600 psi. I would like to run 800 psi through it. We shall see!

I will post more pictures as the gun evolves.

Matt

[High-PSI]

Pics........

[Gun Freak]

Dang! Looks kick ass! This is going to be very nice when completed... bit out of my budget range though

[High-PSI]

This gun was built from left-overs I have lying around. The scope was bought with a gift card I recieved from one of my suppliers, the tank was only $12 to make, the barrel was cheap (don't remember exactly how much), and the misc parts are just made from scrap lying around. The valve, on the other hand, is expensive. I think the total valve setup would retail for around $400 if I remember correctly. But, I get 60% off and I bought these valves a couple years ago for testing. So, that money was spent a long time ago. This gun is being built because I had the parts lying around and wanted to put them to good use.

Matt

[Gun Freak]

Not all of us have 400 dollar valves lying around

[High-PSI]

I spent 3 hours machining aluminum caps to clamp the barrel down to the stock. I made 6 of them. I will post pictures soon.

Oh, I ran the numbers on GGDT and at 600 psi, it says a marble (4 grams) would fire 1,197 fps. I plan on running this gun at 800 psi if the valve will take it (I have to test that first). That shows a muzzle velocity of 1,400 fps on GGDT.

Of course, that is all theoretical. I can tell you it is freaking powerful at 600 psi just messing around in the shop.

I will try to get some Chrony data when the gun is finished.

Matt

[MrCrowley]

Oh, I ran the numbers on GGDT and at 600 psi, it says a marble (4 grams) would fire 1,197 fps. I plan on running this gun at 800 psi if the valve will take it (I have to test that first). That shows a muzzle velocity of 1,400 fps on GGDT.

I will try to get some Chrony data when the gun is finished.

Matt

Should be interesting as GGDT is known to be a bit iffy in the transonic region I believe. Can't recall if anyone has solid chrony data comparing GGDT estimates for transonic velocities but anything you can add will be beneficial.

[High-PSI]

Understood.

One thing to remember, though, one major issue with breaking the sound barrier is turbulence through the valve. A friend of mine is a scientist. We had a long conversation about this. The air enters the valve through a 1 inch pipe. The valve is 1 inch and it chokes down to 1/2 inch (through a ported and polished reducer into the 1/2 inch barrel. The air is flowing well under the trans-sonic region then accellerates to super-sonic in the reducer before the barrel. GGDT varifies this because it give a warning that the barrel is choking the flow.

That being said, all the talk in the word means nothing without experimental data. So, that is what I will do. I will test it and find out how accurate GGDT is in comparison.

Matt