HPA conversion question

[phantaxtic]

Hello

I have converted a co2 mag for the g980 (kar98k) gas powered rifle to HPA.

I'm looking to make this gun as powerful as possible. It won't be for gaming, but more for target plinking.

My questions are:
What is the maximum psi I can run before I blow an o-ring?
What is the maximum psi that I can run before the hammer cannot strike with enough force to open the valve on the magazine?

Any help from a gas rifle tech would be great!

[T-Hell]

why not just buy a pellet gun?

Polar star says 120PSI don't know how you have HPA setup so just letting you know what polar star says

personally I would just buy a pellet gun

[phantaxtic]

I have a pellet gun. The range on a pellet gun vs an airsoft gun with hop up is huge.

My understanding is that co2 has a constant pressure of about 850 psi. I was wondering how much I could push that before I blow an o-ring.

[ShelledPants]

Originally Posted by phantaxtic

I have a pellet gun. The range on a pellet gun vs an airsoft gun with hop up is huge.

My understanding is that co2 has a constant pressure of about 850 psi. I was wondering how much I could push that before I blow an o-ring.

Why not run a test, and stop when you reach the upper limits of fps for what an unregulated firearm is described as, and then document it for anyone wanting to follow your lead.

[phantaxtic]

That's one way of doing it. I want to reach the upper limits of the magazine oring without having to source new ones because i blew them. I want to avoid finding out the hard way if possible.

[brian-i-bunker-u]

well pressure of liquid propane is between 100-200 psI so you should be good for at least that.

[phantaxtic]

The magazine I converted uses 8 g co2 bulbs. From my understanding is that these are at a much higher constant pressure than propane. Any thoughts?

[DipTwit]

IIRC CO2 liquifies around 900-1000 PSI and those little 8g canisters are just a little under that, maybe 850 or so when full. You could google to find out exact numbers but since you seemed to need a ballpark to start with, that's about it.

[ThunderCactus]

Crank up the pressure until you break something, fix it, then dial it back a bit.
You're in uncharted territory here and its not just seals you need to worry about. These guns just arent designed to operate at super high pressure.

[phantaxtic]

So if I tapped directly into the co2 bulb would I need a regulator . .
1. From a 12oz co2 cannister?
2. From a 43ci hpa tank? I believe a hpa tank has a regulator built onto it that steps it down to 800 psi?

[Forever_kaos]

Here's a picture of how I ran mine with Co2, same with HPA;


On HPA, yes the tank it's self has the regulator to bring it down to ~800 or so.

Just like that, no secondary regulator required

[phantaxtic]

So that's the case for a co2 magazine.
For a green gas magazine I would need a regulator to step it down to a usable psi?

[ThunderCactus]

You might. CO2 mags sometimes have smaller orifices to maintain a similar fps compared to green gas mags.

[Kos-Mos]

Originally Posted by ThunderCactus

You might. CO2 mags sometimes have smaller orifices to maintain a similar fps compared to green gas mags.

Most mags are actually completely different.

I took some KAR98 mags apparts, unfortunately they built the CO2 mags the same way as their propane mags. This results in blown o-rings even when used with CO2 cartridges...

Most mags have a nylon/teflon seal and a thin grid/filter to block liquid CO2 from passing. Basically the molecules stay in the mag until the valve is opened enough to let it through. The high pressure of the CO2 keeps the seal, VS. the spring pressure from a GG/propane mag against a o-ring.

Your HPA tank should already have a 750-800psi regulator built-in. That is the standard pressure paintball guns run at. It should be safe to use in your converted mag. The only thing I can see as a problem is the hardware you used to convert the mag, and the method you used. The problem is that the CO2 cartridges are made out of cheap aluminum, usually thin walled. Not much grip for a threaded adapter if you don't reinforce it...

[phantaxtic]

How can the two mags be made the exact same if co2 operates at 800 psi and propane at about 120 psi?