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Posted: Tue Oct 07, 2008 12:07 am
by jackssmirkingrevenge
I understand, however there's nothing to stop the gas from leaking into the magazine, right? Is it a sealed unit?

Posted: Tue Oct 07, 2008 12:22 am
by Davidvaini
its pretty much sealed.. there is such a small thin space that is mainly covered by the bb itself as it goes up into the hopup.. so thats not really a concern.

Posted: Tue Oct 07, 2008 12:33 am
by jackssmirkingrevenge
Have you actually tried this out though, as in hooking up the mag and hop-up to a constant stream of gas?

Posted: Tue Oct 07, 2008 12:38 am
by Davidvaini
I have tested it out with the co2 inflator yes.

Posted: Tue Oct 07, 2008 1:04 am
by Lentamentalisk
Can you link me to a product? I was a little unclear on exactly what it is I should be searching under.
Also, do you have any clue what pressures it can take? Are we talking in the hundred range, or the 800psi range, or what?

edit: celebrating 700 not too too spammy posts!!!!

Posted: Tue Oct 07, 2008 2:41 am
by jackssmirkingrevenge
Davidvaini wrote:I have tested it out with the co2 inflator yes.
Well then, if it works it works ;) I´d still look into ways of sealing it up though to ensure as little gas as possible is lost.
do you have any clue what pressures it can take? Are we talking in the hundred range, or the 800psi range, or what?
I doubt hop-up units are that highly rated, however given the fact that you´re feeding CO<sub>2</sub> through a very small aperture into what is essentially an open system, the chances of having it blow up are fairly small. When in doubt, you could always entomb it in epoxy ;)

Posted: Tue Oct 07, 2008 1:30 pm
by Davidvaini
jackssmirkingrevenge wrote: I doubt hop-up units are that highly rated, however given the fact that you´re feeding CO<sub>2</sub> through a very small aperture into what is essentially an open system, the chances of having it blow up are fairly small. When in doubt, you could always entomb it in epoxy ;)
I agree, Just to add to that, there are plastic hopup units and there are metal hopup units.. Metal ones typically cost a little more but its up to you.

My current setup is a plastic one and it works great.

Posted: Tue Oct 07, 2008 1:36 pm
by Davidvaini
http://www.airsoftpost.com/index.php?cPath=24_71

Those are aftermarket performance ones for Airsoft so they are a little bit expensive.. Still not too bad but...

You would probably wanna buy a cheap airsoft gun for a few bucks and just converting it, or take the hopup and barrel out of there.

I personally like this polycarb one:

http://www.airsoftpost.com/product_info ... s_id=29635

Posted: Tue Oct 14, 2008 7:06 pm
by jonnyboy
Have you gone through a 12 gram yet? If you have how many shots did you get out of it?I'm on the fence about purchasing one. Although a bigger tank is an option. Can you get a video up of it?

Posted: Tue Oct 14, 2008 7:46 pm
by Davidvaini
If I take a few seconds between each burst so the co2 doesnt get too cold I can get around 400 shots+

I will get a video up soon when I get the chance... I've been really busy lately.

Posted: Tue Oct 14, 2008 7:50 pm
by Ragnarok
Davidvaini wrote:If I take a few seconds between each burst so the co2 doesnt get too cold I can get around 400 shots+
That sounds a bit optimistic to me, unless you're only getting wimpish power.

A 12g bulb has about 600 J of energy in it, a 0.2g BB at 328 fps has 1J.
If you really are getting 400 or more shots, considering the limited efficiency of these systems, I doubt you're pushing them much more than 200 fps.

Has this been chronied yet?

Posted: Tue Oct 14, 2008 8:55 pm
by VH_man
I have tried this, amazingly...... i have a spare hicap sitting in my basement.......

this works EXTREMELY well. It fires fast, Reliably, and... runs out of ammo REALLY fast....

Kudos on actually making something that looks good out of it. Im exited to see the final results.

Posted: Tue Oct 14, 2008 9:50 pm
by Davidvaini
if you pause between each shots it allows the co2 canister to stay at around room tempature which gives you sooo many moer shots.. if you hold it down you would probably only get around 150-200 shots.. I tried to chronograph it and I got mixed results.

Sometimes I was getting 300 fps sometimes I was getting 150fps.. Since the hopup is there though you still get a really effective range and shot.

It shoots fast so getting 400 shots really isnt that hard as long as you pause in between bursts... try it out with your co2 inflator :D

My absoulte favorte part of this design is the fact that most Airsoft guns already have a hopup/barrel and magazine assembly.. So it is really easy to convert airsoft guns into high ROF airsoft guns. (only have to mod in co2 inflator.)

Posted: Tue Oct 14, 2008 10:12 pm
by Lentamentalisk
Is there any way to get those high cap mags to actually hold enough, and not need rewinding all of the time? It seems like that is the real limiting factor here. This kind of thing seems ideal for BtB's high pressure full auto, as the pulsed air would greatly increase efficiency and also conserve ammo, while this system could solve the loading issues he has been having.

Posted: Tue Oct 14, 2008 11:12 pm
by Davidvaini
yes, there are different types of airsoft magazines that auto wind via motor. Most of the magazines that auto wind are also larger capacity.

http://www.airsoftgi.com/index.php?cPat ... ek0b6q9ik1

now obviously there are cheaper motorized magazines as well as drum and box magazines that dont auto wind.. but you get the idea...