mod a GBB airsoft gun

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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wyz2285
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Sat Oct 01, 2011 2:35 pm

hi everyone
I´m planing buy a gas blow back airsoft mp5, and I found out that the magazine also serves as the gas chamber. So I thought is it possible to connect a paintball air source to it (with regulated pressure as the operation pressure of the gun) instead of using propane?
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CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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jackssmirkingrevenge
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Sat Oct 01, 2011 3:17 pm

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hectmarr wrote:You have to make many weapons, because this field is long and short life
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wyz2285
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Sat Oct 01, 2011 4:09 pm

:P so it works :idea: !! thx Jack!
but should I keep using the same pressure as the "green gas" used originally or I can go a little bit higher?
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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jackssmirkingrevenge
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Sat Oct 01, 2011 4:13 pm

wyz2285 wrote:but should I keep using the same pressure as the "green gas" used originally or I can go a little bit higher?
I wouldn't go too high, remember that in a hammer valved gun more pressure doesn't necessarily mean more power as it increases the force trying to keep the valve shut.

Also you will be going beyond the design limit of the blowback mechanism, so a marginal system is more likely to break.

In short, unless you plan on upgrading stuff like hammer springs, bolt springs etc. I would keep it "standard".
hectmarr wrote:You have to make many weapons, because this field is long and short life
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wyz2285
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Sat Oct 01, 2011 4:19 pm

hum... so I will have to open the gun, test it and see if I have to mod some internal partes :roll: .If I keep it standard, will the power decease? as air does not behave as propane.
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Gun Freak
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Sat Oct 01, 2011 4:58 pm

Air expands faster than propane, so I think you'd get better velocity... Not sure though...
This would be a sick project...
Polar Star kinda beat you to it though haha.
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jhalek90
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Sun Oct 02, 2011 1:29 am

You keep using "green gas" and "propane" interchangeably, is green gas propane?
jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?
POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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jackssmirkingrevenge
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Sun Oct 02, 2011 1:33 am

jhalek90 wrote:You keep using "green gas" and "propane" interchangeably, is green gas propane?
http://www.airsoft-innovations.com/green-gas-propane
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Mr.Tallahassee
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Sun Oct 02, 2011 2:03 am

I believe the pressure of propane at room temperature is somewhere close to 110 psi or ~7.5 bar. A HPA tank would give crazy numbers of shots if regulated that low. I agree with jsr, I wouldn't risk over pressuring because the gun could go pop (in a bad way) and even if it didn't the performance would suffer without extensive modding.
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Sun Oct 02, 2011 2:34 am

Tapping the mag is a common way of fitting an external rig to an airsoft gun
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wyz2285
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Sun Oct 02, 2011 3:06 am

Air expands faster than propane, so I think you'd get better velocity
I thought this too, and as propane expands and cools down (from liquid to gas) , I should get better accuracy too :roll:
this project is going to kick ass :twisted:
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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wyz2285
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Mon Oct 03, 2011 10:51 am

just another question: if I put a tyre valve on a GBB pistol´s gas chamber(also serves magazine), can I use air instead of propane too? it would be cool if I don´t need to buy gas for my guns any more :P
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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cammyd32
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Mon Oct 03, 2011 2:47 pm

just another question: if I put a tyre valve on a GBB pistol´s gas chamber(also serves magazine), can I use air instead of propane too? it would be cool if I don´t need to buy gas for my guns any more
ermm possibly. You would need a bigger secondary chamber though to go with it, the gbb guns mag won't be able to hold much air for repetitive firing. :)
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wyz2285
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Mon Oct 03, 2011 3:40 pm

but with propane one charge can do at least 30 shots I think, more than enough to finish one magazine of bbs :roll:
CpTn_lAw wrote: :D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
warhead052
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Mon Oct 03, 2011 3:43 pm

Try it. But I would buy another mag so that if it fails, then you can still use it. What sort of pressure would you put into it?
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