Page 1 of 3
4inch coax predictions?
Posted: Fri Jun 08, 2007 10:47 am
by mopherman
hey guys, pyro and I are going to build a 4 inch coaxial with a 2inch barrel later on today. what kind of performance do you think we are going to be getting? with a cauk tube.
thanks i cant use ggt or whatever its called.
Posted: Fri Jun 08, 2007 10:57 am
by jackssmirkingrevenge
if you can give us the full dimensions, pressure you intend to use and weight of the caulk tube i'm sure we can give you an idea.
Why can't you use GGDT? You should try, it's a real gem of a program and saves you a lot of trial and error playing with variables before you start building.
Posted: Fri Jun 08, 2007 11:03 am
by mopherman
ok, 4 feet of 4inch for the chamber, 6 ft of 2inch for the barrel, 100 psi, and i dont know the weight of the tube as i dont have any at the moment.
i cant use ggdt because i have a mac without exel
Posted: Fri Jun 08, 2007 11:17 am
by jackssmirkingrevenge
here's a rough estimate with a 100 gram projectile
Posted: Fri Jun 08, 2007 11:18 am
by mopherman
thanks, thats just what i needed
Posted: Fri Jun 08, 2007 11:36 am
by jackssmirkingrevenge
Interesting to note that that predicted muzzle energy is roughly twice that of a 9mm pistol round
Posted: Fri Jun 08, 2007 11:38 am
by mopherman
sounds interesting. we should have some fun with this one
Posted: Fri Jun 08, 2007 9:24 pm
by rna_duelers
Twice the muzzle energy as a 9mm pistol round...wow...
What are you going to make the piston out of?Try and make it light as possible.The love for big coaxial never ends,how much is this project costing?
Posted: Fri Jun 08, 2007 9:28 pm
by mopherman
were going to try and keep it under 100$. 3inch endcap for the piston.
unfortunately, we didnt get to start the build tonight. no gass money
Posted: Fri Jun 08, 2007 10:10 pm
by jackssmirkingrevenge
rna_duelers wrote:Twice the muzzle energy as a 9mm pistol round...wow...
It gets better, with a 2 inch steel ball as ammunition, the energy is about 100 ft/lbs greater than a 0.44 magnum round
Posted: Fri Jun 08, 2007 10:14 pm
by mopherman
jackssmirkingrevenge wrote:rna_duelers wrote:Twice the muzzle energy as a 9mm pistol round...wow...
It gets better, with a 2 inch steel ball as ammunition, the energy is about 100 ft/lbs greater than a 0.44 magnum round
HOLY WOW! i think this one might have to live down at pyros farm....
Posted: Fri Jun 08, 2007 11:07 pm
by turbohacker
It works great!!!
I reccomend using a slightly filed 3"cap as your piston as seen on my gun.
Posted: Fri Jun 08, 2007 11:13 pm
by mopherman
turbo, i just checked out your coaxial. I love the flanges ( or whatever they are called) how long did the sanded cap take? I only have a drill and a dremmle
edit: to avoid confusion, I meant pyromaniac not pyro. too many pyro names....
edit edit: sorry didnt see your pics. thought you meant the green gun
Posted: Fri Jun 08, 2007 11:21 pm
by turbohacker
Yeah, i just drilled the hole for the bolt dead center and mounted it in my drill press. I then ground and fit a few times with an angle grinder with a flapper wheel. A drill mounted in a vise would probobly work just as well...
Posted: Fri Jun 08, 2007 11:22 pm
by rna_duelers
Ahh yes an 3"endcap,fill it with space filling foam or similar to reduce the pilot volume.Haha I wouldn't shoot something like that in town or a city thats a little crazy and could see something bad happening..
@jackssmirk-A .44 magnum,thats getting out of hand!You gave me links to a website with caluclators to find the muzzle energy of projectile and I can't seem to find them.If you could be as good to post the link that would great.Wanting to find the energy of some of my pneumatics
.