I recently got interested in Airsoft guns (plinking at my home range only) and have been doing a lot of research online. Still, I have some questions. I hope some of you can help me out, and I would be interested in your experiences.
I currently have 9 CO2 Airsoft pistols and 1 Sten MK2 SMG AEG but would like to venture into some GBB varieties hence my questions. Airsoft seems to have some awesome replicas.
Q1 Filling the mags: Fill for 8-10 seconds vs wait til the 'pssst' stops vs seeing vapor come out vs 4-6 one-second squirts?
Q2 Gas: Propane w/wo silicone vs green gas? Green gas is also available w/o silicone oil…why?
Q3 Some articles say shooting with mags upside down or on their sides forces the liquid to be expelled and it’s bad for the gun’s internal seals, etc. Will this be an issue with the Sten that has its mag loaded sideways?
I’m sure I’ll have more questions later. I appreciate any answers and encourage good respectful dialogue.
@William Brooks
I have no experience with gas at all
But I will ask the question to an expert
on our forum (David Reid)
Greetings Frank.
@William Brooks hi there. I have a few AS replicas. All bar 2 are CO2. One is GBB only but the other is capable of using both gas mags and co2 mags. Pistols designed to use co2 are normally of metal construction heavy slides and with strong internal components to take withstand the pressure. GBB on the other hand are generally not built with so much internal steel parts. Both my GBBs are upgraded internally and I use black gas at 220psi. Green gas is usually suitable for most applications except for Japanese made guns which require low power gases. High power gases are based on propane with additional additives. All AS guns require internal lubrication and maintenance. Using gases with added silicon is perfect. Green through to blacks normally have it. Co2 does not so lubrication needs to be done by hand field stripping your gun and magazines. You can buy Umarex Walther 12g maintenance CO2 capsules though which do include lubricants.
I tend to fill my gas mags 4-6 secs bursts 2-3 times.
Thanks Frank and David. I appreciate the info.
David, which AS uses both gas and CO2?
@William Brooks
If I'm not mistaken it should be the
Sig Sauer ProForce P320-M17 FDE Blowback CO2 airsoft
which can do both.

Thanks Frank. That is a nice one. I have both the 320 and m17 in pellet CO2.
Can never have too many right?😅
@William Brooks
https://www.youtube.com/watch?v=r1QjkUjQTaM&t=31s
This is interesting for the non-airsoft 😉
@William Brooks
Taran Tactical Innovations Pit Viper which featured in the movie John Wick Chapter 4.
https://youtube.com/shorts/MFCDVUKhNgg?si=2Y-i8hN6D7EhSqFO
Ordered and received my first GBB - the Sig M17 which handles gas and CO2.
Put it through its paces using gas and got an avg FPS 350. Fairly accurate, but one of the two gas mags seemed to send out more flyers than the other. Got about 3 mags out of a gas charge. Being a newbie with GBB, I'm not sure that I got good full charges.
I'm very pleased with this combo and will not hesitate to venture more into GBBs in the future.

Go ahead, ask me. Do I like Sig AGs? Yes, thanks for asking.
My CCW firearm of choice is the P365. I also like my Colt Cobra and S&W Body Guard.
But I digress...These are the Sig handgun AGs in my collection. (I apologize for the pukey color.) The full metal 226, 229 & 320 are heavy monsters. The two 365s are good for building confident concealed carry & the M17s are great for practicing USPSA.

@William Brooks
You make me a little jealous, that's a nice set of Sigs.
I'm still waiting to buy a Sig 17 6mm (the one in the picture is not mine, it was just for illustration).
But there are so many more nice things to spend money on
For example, I just bought a Leatherman Surge 2
and I would also like to have a Higonokami and an Otter Mercator K55K
Life is hard for a poor man.
But that shouldn't spoil the fun for you, enjoy it 😄