You could get a new spring or put less gas lol

 

Use HFC134 gas my 2 cents lol

 

Get a new spring.

 

What spring are you guys talking about that you think will lower a GBBs FPS?

Nixon,

If the gun has a green gas mag available for it, switch up to green gas or propane. If it's still to high, then drop down to HFC 134a/duster gas.

 

Considering it's a CO2 gun, not much can be done in the way of FPS mods. Maybe a new flow valve?

 

it runs off of green gas/propane while KC-02 is the name it already uses green gas... however ive never heard of HFC134 i have probably never seen it used either can you tell me what it is and where to pick some up. thank you for all the ideas ... keep em coming

 

it runs off of green gas/propane while KC-02 is the name it already uses green gas... however ive never heard of HFC134 i have probably never seen it used either can you tell me what it is and where to pick some up. thank you for all the ideas ... keep em coming

HFC134 is also known as duster gas. It's the kind you use for cleaning keyboards and what not.

 

i've heard of people mixing duster and green gas

 

You don't mix them. Green gas or propane is pretty available. HFC134a is "Duster Gas" or the gas that you use to clean computers. You can buy it at OfficeMax. You will either need to purchase or produce and adapter so that you can use it.

 

You don't mix them. Green gas or propane is pretty available. HFC134a is "Duster Gas" or the gas that you use to clean computers. You can buy it at OfficeMax. You will either need to purchase or produce and adapter so that you can use it.

they would put say 1 second of propane and 1 second of duster gas into the magazine. It's like watering it down.

 

You know, I've heard of people doing that thinking that they're somehow diluting the pressure, but I've never seen chrono results that say whether it works one way or the other. Chemistry theory would dictate that as long as you have liquid propane, the whole mag is under the pressure that the propane exerts. How then that manifests from shot to shot when bits of propane and bits of 134a are released (maybe in different quantities with each shot, depending on how homogeneous the mixture?) would be hard to determine. I'm out of town right now, but when I get back (if I remember), I'll run some 50/50 propane/HFC134a chrono tests. Somebody bump this thread on like, Wednesday and tell me I promised.

 

You can always make a tiny washer to act as a restrictor for airflow. Not too hard to do if you know how to fully take apart your gun. BUT, unless your advanced in gas gun knowledge, I'd just buy a diff gun, because messing with gas stuff can cause great bodily harm (no joke).

 

ok thanks this forum has exceeded my expectations thanks for your help.

 

Mixing would not work you can't change the pressure by mixing. If you add duster then green gas it will just go to the pressure of green gas if you add green gas then duster it will just go to he pressure of the duster. Its physics

 

what about a fps reducer ya know those little things that screw on the end of a barrel, idk if that would work tho

 

Mixing would not work you can't change the pressure by mixing. If you add duster then green gas it will just go to the pressure of green gas if you add green gas then duster it will just go to he pressure of the duster. Its physics

It wouldn't matter which gas was added first. If mixing gasses doesn't work, it wouldn't work because the gas that exerts more pressure would always exert that pressure, essentially negating the effects of the lower pressure gas. That's if it doesn't work. It might work, we don't know one way or the other yet.

 

well think of it like pumping up a tire. If you put in x amount of air and y amount of, oh i don't know, carbon dioxide, then the total amount of pressure would be the pressure of x + the pressure of y. If you add different quantities of each say 25% air and 75% CO2 then theoretically, the pressure would be proportionate to the solution (assuming the two gasses have equal densities) If, however, gas y has a higher density then gas x, y will "sink" to the bottom of the magazine and gas x will be the first to be expelled, applying but still with the added pressure of both. Once gas x has been fully used, then gas y will be used because it will expand to prevent a vacuum. The pressures could also be modeled like this: Sally(gas x) pushes a cart North (bb)with 105 lbs of force. John (gas y)pushes the same cart in the same direction (in our case, the output valve) with a force of 150 lbs. the total amount of force exerted on the cart would be 255 lbs N.

I tried to make this as clear as I could but I went back and thought it was kinda confusing :/ anyways that just my thoughts on what would happen. Only testing can get the actual answer.

 

The problem with all of that is that we're dealing with liquid, not gas. Both propane and HFC 134a remain in liquid state in the reservoir, and only transition to gas as released. So if you have any liqiud propane in the reservoir, it's exerting its condensation pressure (at room temperature) on everything in the magazine. How that would affect the liquid 134a, I don't know. But gas dynamics and liquid dynamics are going to be a bit different.

 

The problem with all of that is that we're dealing with liquid, not gas. Both propane and HFC 134a remain in liquid state in the reservoir, and only transition to gas as released. So if you have any liqiud propane in the reservoir, it's exerting its condensation pressure (at room temperature) on everything in the magazine. How that would affect the liquid 134a, I don't know. But gas dynamics and liquid dynamics are going to be a bit different.

oh yup, forgot about that. *facepalm*

 

shorten the inner barrel, or open some ports on it.

 

Btw, the shorter it is (or the earlier the gas reaches the ports), the lower fps you get... so try not to over do it. You need a tube cutter tool to cut the brass tube to preserve the diameter.

 

It wouldn't matter which gas was added first. If mixing gasses doesn't work, it wouldn't work because the gas that exerts more pressure would always exert that pressure, essentially negating the effects of the lower pressure gas. That's if it doesn't work. It might work, we don't know one way or the other yet.

However if you added duster second then the green gas would fill the duster canister because the pressure must even out. Which would make the gas duster pressure.

 

Again, if we were talking about this stuff in a gaseous state, you would be right. We're not, we're talking about these propellants in a liquid state. That changes the game. This isn't a hard concept to grasp, it's GBB 101. Propane, in liquid state will never be at the same pressure as liquid HFC 134a at the same temperature.

 

Again, if we were talking about this stuff in a gaseous state, you would be right. We're not, we're talking about these propellants in a liquid state. That changes the game. This isn't a hard concept to grasp, it's GBB 101. Propane, in liquid state will never be at the same pressure as liquid HFC 134a at the same temperature.

I thought that duster was in a gaseous state when it was in the can. If not you are completely correct.

 

No, it's not. A GBB couldn't function off of a gas that low in pressure in a gaseous state. You'd get one shot with any real power, then maybe one more fart of a shot, then it'd be empty.