R134a

[busta_cap]

Kind of an interesting find... Aparantly the molecular weight of R134a is very heavy.. Just thought I would share..

Some data info on Propane(green gas), red gas (HCFC-22, R22) etc etc..

Propane(Green gas) @ 70F is 109PSI, 44 Molecular weight

R22(red gas) @ 70F is 128PSI, 86 molecular weight

R134a(duster gas) @70F is 70PSI, 102 molecular weight

Makes sense now doesn't it? ](*,)

Also, Nitrogen's molecular weight is 28...Pure oxygen is around 32..and since the air in the lower atmosphere is about 70% nitrogen anyways, 'air' is sitting right around 29 weight.

So theoretically what this means is that if we really wanted to get the most out of our gas guns, we really should be using a lighter gas like nitrogen or compressed air that is regulated from a high pressure tank. Obviously because the magazines these guns use are of low quality metal and seals, we can't really run these low density gases efficiently.

Any thoughts or comments please feel free to add.

[azsarge]

Propane works better.

I'm not a chemist, though.

[busta_cap]

Propane works better.

I'm not a chemist, though.

better Than..r134a? Well yes.. than Green gas? Then yes..cause the lack of silicon. Silicon is good on bolts and moving stuff..But terrible for your hop up and barrel.

[azsarge]

Propane works better.

I'm not a chemist, though.

better Than..r134a? Well yes.. than Green gas? Then yes..cause the lack of silicon. Silicon is good on bolts and moving stuff..But terrible for your hop up and barrel.

Without chronoing it to be sure, propane has comparable range and blowback to green gas.  It is much less expensive, and is available almost everywhere.

Vince and I were just discussing today the fact that I don't care for the extremely light viscosity silicon that is mixed into green gas.  I prefer to lube the parts on the gun with shock oil or teflon grease and run the dry propane.  

Like you said, it keeps the hopup rubber dry, and it's more consistent.

[busta_cap]

Propane works better.

I'm not a chemist, though.

better Than..r134a? Well yes.. than Green gas? Then yes..cause the lack of silicon. Silicon is good on bolts and moving stuff..But terrible for your hop up and barrel.

Without chronoing it to be sure, propane has comparable range and blowback to green gas.  It is much less expensive, and is available almost everywhere.

Vince and I were just discussing today the fact that I don't care for the extremely light viscosity silicon that is mixed into green gas.  I prefer to lube the parts on the gun with shock oil or teflon grease and run the dry propane.  

Like you said, it keeps the hopup rubber dry, and it's more consistent.

Well that is also dependent highly on temperature and other variables that effect the liquid gas. I am pretty positive that green gas and propane at the same pressure will yield an fps tolerance of <10%. I would actually venture to say propane would yield a higher FPS consistently due to the fact you have no additional silicone lingering in the barrel. Another issue with gas guns is that a more dense gas such as propane vs c02 or nitrogen is that there will be gas lingering in the barrel after you fire, making subsequent shots susceptible to having to move that denser gas out of the way first. With nitrogen,air,c02 you don't have this issue. if someone could actually chrono a GBB M4 on full auto I would bet that the farther into the mag you get with a denser gas the fps will drop a bit.

And yeah , I agree with you 100%. I am curious if a standard GBB mag could take a low pressure (100-150psi) charge of nitrogen or compressed air...This could easily be accomplished with a HP to LP rig you just need to use a 'propane adapter' to fill the mag.

[Whiskey11]

That also brings up the issue that HFC134A is illegal to vent into the atmosphere in the US and has been since 1995.  

Source: http://www.epa.gov/ozone/title6/609/subsumm.html

Anyway, technically venting any of them is illegal, which is why other airsources such as HPA or Nitrogen would be better, it's just impossible to include a PSI regulator and make the magazines strong enough and cheap enough to make them economical.  I've always retained that Gas in Mag guns are a cool concept for full sized rifles, but being tethered is still the way to go.