Posted: 02/03/2008 17:52 PM Post subject: Update: My most powerful pneumatic yet the K.A.M.G
Experienced n00b
Joined: 01 Dec 2007 Posts: 1516 370.57 Spud Bux
It is not that huge and doesnt stand any chance in power against the SCTBDC but its power is quite awsome for its size(its sort of like a mini SCTBDC)
I name it the K.A.M.G(Kick A$$ Metal Gun)
It is very impressive to watch fire the recoil blows it of its stand and the blast makes plywood fly away.I have held this while fireing and the recoil is amazing.I have only pressurized it up to 160psi because it is so loud.
I cant use it outside of my garage because of the noise it deafens me in the enclosed garage.
My dad is afraid of it and wont let me use it when my brothers are around because hes afraid they will get hurt by it somehow.
This is the product of some upgrades to this gun
http://www.spudfiles.com/forums/200psi-metal-cannon-updatelots-of-dama ge-pics-t12918.html
I will put a pressure gauge on it so I can pressurise it with dry ice to
300-400psi
I will get a 10ft 1in barrel and a 10ft 1.25in barrel for it.
I realese the presure with a burst disk which burst a second or two after I open the ball valve.
I have gotten it through 3 pieces of plywood before stopping with a CO2 cartrige.I will try some heavyer ammo and see how many peices of plywood I can get through with that.
And it would be really helpful if someone could GGDT this for me with 400psi and a 10ft long 1in barrel firing a co2cartrige.
The specs
Chamber:12in of 1.5in steel pipe and 24in of 1in steel pipe 45.57ci
Barrel:4ft 1insch40 pvc and 10ft 3/4in thinwall pvc rated to 200 psi
(would it be safe to use the thinwall barrel at 400psi)
Valve:Ball valve actuated burst disk
Fill setup:Shrader valve with in ball valve to close when I use it above 200psi.
Pressure used:100-200psi currently but hope to soon use 300-500psi
Enough talk heres some pics
Ill add some damage pics and maybe a video because pictures dont do the justice of how powerful this thing is.
The gun without the chamber extention on next to my bike pump with the 4ft 1in barrel on
The chamber extention and, my feet
The chamber and my feet again
The fill setup
A burst disk that has burst
The union I added on
Thats it, tell me what you think
Damage pics coming soon
Update:
Chamber volume incresed and more barrels
Have a 5ftlong 1.5in SDR21 golf ball barrel
10ft long 1/2in sdr21 paintball and marble barrel
10ft long 3/4in Sdr21 barrel(bought the wrong size for another gun that it was meant for use with)
4ft long 1in barrel(rarely used anymore)
Chamber volume was 45.57ci but now it is about 65ci
Put on a 24in long peice of in pipe I had laying around.
Some pics
The KAMG with the golfball barrel attached before the chamber extention
with the paintball barrel on(bent a little I know)
With the 3/4in sdr21 barrel on
Thats it for now i really hope to get the chance to upload some damage pics today or if I can get hold of my stepmums camera a video.
Posted: 02/03/2008 18:57 PM Post subject: Re: My most powerful pneumatic yet the K.A.M.G
Lord of Karma
Joined: 19 Dec 2006 Posts: 2058 5232.84 Spud Bux
bigbob12345 wrote:
And it would be really helpful if someone could GGDT this for me with 400psi and a 10ft long 1in barrel firing a co2cartrige.
With a 12g cartridge, the fit will be quite loose, and you didn't actually give a valve diameter, so these figures are going to be pretty wild.
760 fps, loose cartridge, 1.5" valve, air.
A drop in valve diameter to 1" loses you 20 fps, a cartridge wrapped in electrical tape will gain around 90 fps. At these speeds, although GGDT says otherwise, this is very close to CO2's speed of sound, so shockwave losses using CO2 will cost you around 100 fps.
I just let this thing out on some plywood and it was absolutly devestating it would go through 4 layers before putting a dent in my garage at the max I can do it 200psi I filled the barrel with water and let one off while I was holding it bad idea it threw back with so much force that it yanked itself out of my hand good thing it landed on grass.It may not be big but it destroys anything you put infront of it.
Edit: Ragnorok thats about what I expected good and to bad about the energy loss with the CO2 maybey Ill try to get my hands on some heilium and expand the chamber size even more and use a 20ft barrel.
co2 catridges are relatively light.... try something heavier - it will increase the muzzle energy and the speed of sound in co2 won't matter that much...
bolts, nuts or steel rods would be ideal
Ive got some damage pics to upload Ill upload them but they just dont show the true power of this gun I was going to do a vid but my dad had to leave and he doesnt let me use it when hes not around.Two weeks from now Ill get some dry ice,pressure gauge a longer barrel and bigger chamber.
Good job bigbob, that performance is impressive for such a small bore and low pressure.
If you had a pressure source like an HP tank or compressor, you could increase performance by putting the trigger between the filling hose and the chamber rather than right before the firing valve. Doing this would increase reliability and performance, as flow would be less constricted when the disk failed.
It surprises me that this is loud. I can compare it to my MBDC, which has a much larger chamber volume and an equivalent bore size, runs on 500 psi, and has a very similar BD setup (except it incorporates my above suggestion), but makes only a small pop when fired. I think I may have damaged my hearing somehow in this hobby *cough*oxyMAPPhybridincident*cough*.
DYI:Thanks for the comment and yes it is very loud especialy with the barrel not on.Loud enough for my neighbors to take a peek out door into our backyard after me fireing it inside our garage with the doors closed at 80psi.
The burst disk makes such a huge difference in performance It has just become my favorite valve.Im really getting addicted to metal and high pressures even though I have acsess to pressure rated pvc in all sizes.
omg Im becoming you
Nomame:yes it seems that whenever someone puts there feet in a picture they are wearing socks
Well THERE'S your problem. Firing the MBDC inside at 80psi is a lot louder than firing it outside at 500. If you move this outside it won't be nearly as hard on your ears.
I have fired it outside it makes a difference but its still very loud.
Or maybe I just dont know the true loud sounds produced by larger cannons and it just seems loud to me or i have good ears or as you you metioned you have bad ears.
Who knows why but its loud.
Edit: or its beause your MBDC has a longer barrel which would be a reasonable explination.
The pressure at the end of the barrel on your design is ~82 psi, while the pressure at the end of the barrel on the MBDC is at least 250 psi. Which means that even with the surface area difference, the flow rate out the barrel of the MBDC is higher than that of the KAMG, and with all else equal (which it is, as flow is not constricted in any way on either design), the MBDC should be quite a bit louder.
As you said, either you have sensitive hearing, or I have damaged hearing, or (as I suspect), it's a combination of both.
DYI:I agree with you I think its a combanation of both those because I dont think Ive ever had my ears ring which is quite suprising considering I have been ito this hobbie for a little under a year.
sthorne:I have used CO2 cartriges;potatoes(duh),1/2in pvc with wadding(awsome damage),wodden dowels,water(kicks like a beast), and 2in long metal rods wrapped in duct tape to fit.
A couple days ago I would of said my favorite ammo is CO2 cartriges but now I will have to say 1/2in pvc 3ft long with wadding of course just because of the astonishing damage it does a close range(clears 5 layres of 1/2in plywood).
Update
Larger chamber, more barrels
See above.
Ive been experimenting a lot with this gun especially with alternate burst disks and have found the ultimate burst disk matierial...Brown tape
it only would work for 1in unions and under but it is perfect with it adding pretty accurately 35psi per layer(except for if there is one layer in which it bursts at 27psi)but of course that information is for 1in unions.
I have yet to get the pressure gauge because I cant find any that go above 200psi.
And when i do get a pressure gauge i want to know if it will be safe to use the thinwall barrels at 500psi.
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I filled the barrel with water and let one off while I was holding it bad idea it threw back with so much force that it yanked itself out of my hand good thing it landed on grass.It may not be big but it destroys anything you put infront of it.
Well 
