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12 gram co2 cartridge semi auto rifle (co2 cardridge rifle)
Posted: Tue Jun 23, 2009 10:00 pm
by twizi
i made a bet with my friend that i would have a working proyto type by the end of the month
i have acess to a lathe drill press and a 200 budget(yes i have a budget)
if i make it work i get 500 bucks
i figure im gonna have a firing pin hitting the cartridge in the back like a reel rifle then have a gas tube desighn like an m16
any thing would be appreciated[/b]
Posted: Tue Jun 23, 2009 10:27 pm
by Hotwired
6 days to have a working semi sparklet cannon.
Hope you're on holiday.
I might think of a blowback design. The cylinder will jet out irregardless but there should be enough gas pressure to recock the firing pin to be latched until the trigger is pulled again.
Again because the cylinders are somewhat self-propelling, having the magazine open to the "chamber" won't stop it from working. You would get a more powerful launch if it was fired from a well sealed chamber but at the cost of more parts and reliability.
/random thoughts before going to bed
Posted: Tue Jun 23, 2009 11:23 pm
by THUNDERLORD
Pretty broad, sloppy written specs.
And I'm not fully understanding them...
But what about having a cloud or vortex,
And while it's firing pneumatically,
the trigger has an electric switch activating a solenoid similar to ,
for example a tattoo needle, alarm bell or electric stapler that moves back and forward ejecting fake shells from a magazine...
Any thoughts on that? 8)
Posted: Tue Jun 23, 2009 11:33 pm
by jackssmirkingrevenge
THUNDERLORD wrote: the trigger has an electric switch activating a solenoid similar to for example a tattoo needle
When I accompanied my (then) g/f to get her tattoo done all I could think about was "dakka dakka dakka dakka!"
Combine that mechanism with
this breechand you're sailing

Posted: Wed Jun 24, 2009 7:19 am
by twizi
so i would stick on a firing pin to your idea jack
Posted: Thu Jun 25, 2009 2:28 pm
by Solar
I don't know about using the flow through the 12 gram. It is very slow and will waste a lot of gas. The earlier post regarding using a sealed chamber is the better idea. The design parameters are vague and looking at the suggestions it makes me wonder: Are you trying to have it launch the 12 grams for ammo as well as use them for fuel? You need a way to eject the spent 12 grams if not.
Posted: Thu Jun 25, 2009 2:35 pm
by twizi
i plan to use the co2 12 gram like a bullet i have made a fireing pin and a hammer and gas tube is all sealed up
its like an m16 with 12gram as a bullet and no ejection just in .75 cal
Posted: Fri Jun 26, 2009 11:15 am
by ramses
does it have to be semi? full auto could actually be easier.
Posted: Fri Jun 26, 2009 1:44 pm
by twizi
no it could be semi or full auto i thought semi would be easier i have completed it i got my stock today now i stuck it all together but i need more co2 cardridges
Posted: Fri Jun 26, 2009 1:52 pm
by ramses
be sure to post the results! I demand videos!
Posted: Fri Jun 26, 2009 2:31 pm
by twizi
ill see my camera has be f#$k up normaly so ill try but its for the contest so i might say this is a proytotype then ill make a full auto versian
Posted: Fri Jun 26, 2009 2:35 pm
by ramses
oh, by all means save it for the contest.
Posted: Fri Jun 26, 2009 2:42 pm
by twizi
yeah i will see what i can due ill see if i can post one damage pick if your lucky two
Posted: Sun Jun 28, 2009 3:36 am
by Solar
I'm not so sure the porting on a 12 gram has enough flow to give you what you are looking for. It will be more like a rocket than a burst I would guess.
Posted: Sun Jun 28, 2009 5:22 am
by inonickname
It's simply newton's law (every reaction has an equal and opposite reaction blah blah blah..). CO2 carts will easily propel themselves rapidly, in a similar fashion to a steam rocket. You will probably double the performance if you make a convergent diameter or de laval nozzle for each cartridge. (they're spewing out liquid CO2, which will turn to gas as it hits the air..so you want a nozzle for it to expand against) If the barrel was an excellent fit to the cartridge then the gas could be tapped to actuate a pneumatic cylinder to recock the gun.
By the way, put a very long barrel on it with a lot of ports at the end (muzzle break) otherwise the liquid CO2 will cause a very "up" oriented flightpath.