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What size coaxial should I make?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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What size coaxial should I make?

Unread postAuthor: origin unknown » Mon May 28, 2007 9:23 pm

I am having trouble on deciding on the size of the new coaxial I want to make. I am planning on making the piston out of wood. I just need some suggestions on what my barrel size and chamber size should be.

EDIT Can someone use their GGDT for me since I have an apple computer which I cant install GGDT on? I will PM you the different specs.
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Last edited by origin unknown on Mon May 28, 2007 9:33 pm, edited 1 time in total.
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Unread postAuthor: hi » Mon May 28, 2007 9:29 pm

I have a 1.5'' chamber and a .75'' barrel and it works great because in order to make barrel support in the chamber i just take a peice of 3/4'' pipe and cut it in half and have instant barrel supports.
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Unread postAuthor: Velocity » Mon May 28, 2007 9:29 pm

2.5" barrel, 4" chamber? You could use a 3" PVC endcap as the piston instead of wood (I have wanted to build such a coaxial for a while...)
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Unread postAuthor: frankrede » Mon May 28, 2007 9:45 pm

2"sch 80 chamber with 1.5"fittings

barrel 3/4"sch 80/
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Unread postAuthor: hi » Mon May 28, 2007 11:57 pm

14'' chamber with a 1/2'' barrel, that i would like to see. that would be kinda rediculous, but so cool.
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Unread postAuthor: jackssmirkingrevenge » Tue May 29, 2007 1:55 am

The question really is what do you want to shoot, how big do you want to make it and what are you pumping it with? If you use a 1.5 chamber and 0.75 barrel like hi suggested and make it long enough you'll have a nice fast marble shooter of managable dimensions that can be easily taken up to pressure with a bike pump.
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Unread postAuthor: noname » Tue May 29, 2007 5:39 pm

I'll give you some fun 8" PVC if you want. :D I'd have to charge a couple bucks a foot though, but no more than $5.
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Unread postAuthor: hi » Tue May 29, 2007 9:05 pm

noname wrote:I'll give you some fun 8" PVC if you want. :D I'd have to charge a couple bucks a foot though, but no more than $5.


how much do you have?
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Re: What size coaxial should I make?

Unread postAuthor: A-98 » Tue May 29, 2007 9:15 pm

origin unknown wrote:EDIT Can someone use their GGDT for me since I have an apple computer which I cant install GGDT on? I will PM you the different specs.
you señor, are officially in the elite group.

anyway, back on topic.

it all depends on your ammo. i would go for a nice 2-3" chamner with a .75-1" barrel.
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Unread postAuthor: noname » Tue May 29, 2007 11:51 pm

Hi, I had 20 feet, but used 6 or 7 for a not yet finished soccer ball gun, so I have around 13 or 14 feet of it. It's 8" Sch 40, rated to 160 psi, ASTM rated and all that other writing that's on PVC.
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Unread postAuthor: noob of noobs » Sun Jul 01, 2007 5:33 pm

Hi, for your "3/4" inch barrel and "1 1/2" inch chamber, about how long do you think the chamber and barrel should be?
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Unread postAuthor: hi » Sun Jul 01, 2007 6:26 pm

noob of noobs wrote:Hi, for your "3/4" inch barrel and "1 1/2" inch chamber, about how long do you think the chamber and barrel should be?


it can be as long as you want it to be. mine was around 9 feet, but there is no advantage over one that was 4 feet. i made it long thinking it would give me more power, but it didnt. i still got maybe 800 fps out of it, but one half the size would be about the same.

i would say no less than 8 inches, no longer than 5 feet. it is truely up to you how long it is. i like to have the barrel flush with the bushing, but you can extend it about a foot if you want to.
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Unread postAuthor: noob of noobs » Mon Jul 02, 2007 4:09 pm

Thanks, I'm gonna try a 3 footer (plus the pilot and schrader) Also, how high should one pressurize such a cannon? I heard coaxials are a lot weaker since there's air pressure being exerted on the barell.
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Unread postAuthor: iPaintball » Mon Jul 02, 2007 4:26 pm

Ill run GGDT for you if you want me to. I also have a Mac, but I can use my mom's laptop for GGDT.
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Unread postAuthor: origin unknown » Mon Jul 02, 2007 5:20 pm

I am making a coax pistol with a 1.5" chamber and a 1/2" barrel.
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