Propylene and GBBR's anyone tried it?

[Kos-Mos]

I have first hand experience with a WE SCAR Open bolt in -20C weather.
Yeah, same gun you have.

VN-style 20-rnd, removed the end spring spacer to bump to 24rnd.
It was at an indoor venue, in Valley-Field, so wind was not a factor. Cold only.

Propane mag, topped-off and then heated to body temperature (that means that there was actually MORE propane in the mag than usual) COULD NOT empty 24rnd. Barely shot 10 before spraying ice in the rifle body.

That is because the ambient air around the mag is used to heat the magazine in normal conditions. It took half the mag for it to become freezing cold and ice to form on the shell.

Tested with CO2 mag also. That was a bit better. Weaker kick than usual but the gun fired all the rounds properly. The cartridge was frozen in place in the magazine shell.

Both tests where on SEMI, 2 rnds per second, in 5 rounds "bursts", spaced 5 seconds each.

I have not tested MAPP yet, but will probably this winter.

I have also shattered a nozzle on the second run of the CO2 mag, and could not double the test.

As for semi/full,
I played this week-end. Most of the time SEMI.
But please, explain to me how you would have engaged 7 players at 50' when they saw you and turned to shoot?
I flipped the switch to AUTO and burst. Got 4 of them before I was hit.

[MaciekA]

Originally Posted by Fox62

Oh, so you don't run gas guns yourself? Helluva first hand experience.

Really? Every game in winter is on the -20 - -40 ºC range?

January in Calgary was just dandy (least the weather...). Don't think a day was below -5.

If all your games are on that range, well, then yeah, try propylene or whatever. It's like 3 months straight of -20 - -40 days, I understand. GBB's are bad for ya.


Fox.

Hey, extraordinary claims require extraordinary evidence. This forum is full of Canadian airsoft players who play in the winter all the time every year, year after year. I say that this community and our collective anecdotal experiences in our weather environment arguably constitute a community of experts on the topic at hand. You made an extraordinary claim contrary to the general consensus as well as contrary to the generally-accepted science, which says that the pressure of Propane at what we consider to be cold is absolutely not qualifiable as "fine".

Remember, we don't require a mountain of data to back up a well-known, widely-accepted and repeatedly tested and observed consensus that confirms itself every winter, and you can't accept to not have a dozen people jump down your throat when you contradict common knowledge with a one-liner with nothing convincing to back it up. So convince em'.

[ShelledPants]

[Fox62]

Originally Posted by Kos-Mos

I have first hand experience with a WE SCAR Open bolt in -20C weather.
Yeah, same gun you have.

VN-style 20-rnd, removed the end spring spacer to bump to 24rnd.
It was at an indoor venue, in Valley-Field, so wind was not a factor. Cold only.

Propane mag, topped-off and then heated to body temperature (that means that there was actually MORE propane in the mag than usual) COULD NOT empty 24rnd. Barely shot 10 before spraying ice in the rifle body.

That is because the ambient air around the mag is used to heat the magazine in normal conditions. It took half the mag for it to become freezing cold and ice to form on the shell.

Tested with CO2 mag also. That was a bit better. Weaker kick than usual but the gun fired all the rounds properly. The cartridge was frozen in place in the magazine shell.

Both tests where on SEMI, 2 rnds per second, in 5 rounds "bursts", spaced 5 seconds each.

I have not tested MAPP yet, but will probably this winter.

I have also shattered a nozzle on the second run of the CO2 mag, and could not double the test.

As for semi/full,
I played this week-end. Most of the time SEMI.
But please, explain to me how you would have engaged 7 players at 50' when they saw you and turned to shoot?
I flipped the switch to AUTO and burst. Got 4 of them before I was hit.

That's more like it.

[pugs144]

Originally Posted by Deltastone

I suggest to ignore him - because he either has no idea what he is talking about or is deliberating trying to waste time - and continue with the discussion as posted.

Every forum needs their own "Ronan."

[Drake]

Wave goodbye to Fox62, everyone.

[SuperCriollo]

Sadly not the first time he goes all smart ass, and the thread becomes a massive argument. Was it a perma-ban if I may ask ?

[Drake]

Originally Posted by SuperCriollo

Sadly not the first time he goes all smart ass, and the thread becomes a massive argument. Was it a perma-ban if I may ask ?

His contribution to the forum was hovering somewhere around nil, so yeah.

[Basic-Wedge]

I haven't seen any numbers published yet, so I ran some BBs through my chrono to compare propane to propylene. Here's what I got:

Propane

404.4
397.5
378.5
386.7
390.2
398.8
387.5
375.8
388.5
381.8
Average = 389.0

Propylene

434.4
434.1
421.2
414.2
416.5
407.5
410.6
407.3
399.0
415.8
Average = 416.1

- The test was conducted in 19℃ temperatures, 35% humidity.

- Propane used was Coleman brand. Propylene used was Bernzomatic brand.

- The rifle is an upgraded WE M16A3 with a 500 mm Angry Gun tight bore barrel. The NPAS valve was opened more than normal for consistent gas flow.

- The magazines were new, previously unused WE M16 types of the latest design, well marked to avoid confusion between gas types.

- Each mag was purged, fully filled, purged again, then fully filled for the test.

- The mags remained together for thirty minutes prior to the test, so their contents were at the same temperature.

- I fired one throw away round prior to testing, then fired five rounds with each gas, switching back and forth to keep the magazines from becoming cooled by their respective gases.

- I threw out the highest and lowest velocities for each gas to avoid anomalous reading (although the highest and lowest numbers were not inconsistent with all the other readings).

The real test will come when temperatures drop lower. For now, it can be inferred that propylene delivers slightly higher velocities than propane (about 7%) in warm weather.

Of further note: the type of propylene I used had a scent added to it, just as propane does. If you don't like the smell of propane, you will hate propylene. It has a very sharp and acrid sort of scent.

I'm looking forward to seeing numbers from other testers, especially in cooler temperatures.

[lurkingknight]

I think the power fall off is less dramatic in colder temps but you'll still get down to the point where it will be too cold to function. Even with propelyne, dedealus' m14 would vent the entire mag occasionally, and I don't think scotland is as cold as canada.

[Eeyore]

Having tried MAP out in GBBR's I can say it works great. But I'll never use it ever again. It was like a skunk exploding in my face every time I fired a shot. That stuff is toxic.

[Drunk_Albertan]

Good riddance to Fox. I've yet to read a thread where he contributed to anything other than starting arguments.

Oh, btw Fox, when and if you were in Calgary in the winter and it was 5 dec C, it was during a Chinook. Google that shit. It still gets to -30 here too.

[Wrath144]

Because I'm bored:
These values are taken from air-liquide's vapor pressure tables.
http://encyclopedia.airliquide.com/E...a.asp?GasID=54
http://encyclopedia.airliquide.com/E...a.asp?GasID=53
Because they are vapor pressure tables, we know they are for a saturated mixture, which is more often than not the state found in our magazines during use. A saturated mixture simply means there is both liquid and vapor existing in the container at the same time.

Propylene at 0* C -> 600 KPa
Propane at 0* C -> 450 KPa
25% pressure difference

Propylene at 19* C -> 1100 KPa
Propane at 19* C -> 850 KPa
22.3% pressure difference

So there's nowhere in here we can assume a linear relationship for anything, so there's no point in any further calculations. Not to mention, there is way more at play here than just temperature and pressure. I could write a thesis on it... nope.
Rob's results have a 6.5% velocity difference at 19*C, and since there is a higher relative pressure difference at 0*C, I hypothesize that at lower temperatures we will see a velocity difference higher than 6.5%. A conservative estimate would be 9%, but that's just a completely arbitrary number I came up with.

Fun Facts:
- Propylene has the same pressure at 0*C that Propane does at around 7*C. Do not assume they will act the same at their respective temperatures, but its food for thought.
- Propylene is "Non recommended, significant swelling" for most common o-ring materials. Possible effects on test results could include gas valves not opening completely due to increased friction from swollen o-rings, or leaks cause by excessive swelling of o-rings.

[4th year Mechanical Engineering student for hire....]

[Basic-Wedge]

Is there any way you clones could stop chatting about the weather in Calgary, so those who are focused on the subject at hand won't have to deal with your ramblings?

Perhaps a mod could filter the irrelevant content out of this thread? It would be nice to actually use this as a resource.

[MaciekA]

Originally Posted by Basic-Wedge

I haven't seen any numbers published yet, so I ran some BBs through my chrono to compare propane to propylene. Here's what I got

Possibly a dumb question on my part, but is there some way to mix gasses of this kind to "blend" their temperature->pressure properties depending on the desired application?