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Green Gas Magazine Empties After Few Shots

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21K views 10 replies 7 participants last post by  Guges Mk3  
#1 ·
I'm sure what I'm experiencing has been encountered by others, documented, and fixed many times before. But for some reason I'm lacking the "Google-Fu" to find it tonight.

My boss bought a new Stark-Arms G18c with 2 extra magazines, a propane adapter, and 100% silicone oil.

He loaded them up with .20's, filled the mags, and then got 4 - 8 shots from each before it fizzled out.

I was convinced he was doing something wrong so I had him bring it to me.

I lubed the rings, lubed the propane adapter, warmed the mags and tank by the heater for a while.

I moved away from the heater :cool:, then filled each mag until I heard them equalize, then gave them another shot.

I tried each magazine, and from each I only got a 4 - 8 shots. The warmest of the 3 mags, I got about 14 shots out of the first time, and the 2nd time 6 shots.

I've never fired one of these without gloves on before (that I can remember). If I did, I don't remember having my hand splashed with so much propane on each shot.

My thought is that this gun is dumping excessive propane, holding the striker valve open too long on each shot, but I'm not sure what to do to correct it.

Thoughts / recommendations?

Thanks.

-EB
 
#2 ·
Could be an air pocket in the mags.

Air requires a lot of pressure to compress, way more than you'll get from propane or green gas.
If there is air in the magazine, you can not fill it completely with the propellant gas.

Try purging the magazine chamber.

There are a couple methods to do this.

Fill the magazine as normal, turn the magazine right side up, then manually depress the main valve for a second or two to release some gas. Since air is lighter than propane/green gas, the air will be forced out.

The second way is to hold the main valve open while filling. Be careful with this method since you will have liquid gas coming out of the top of the mag.

Those are free methods to try before you spend money on spare parts that may not be needed.
 
#4 ·
Probably an internal hammer issue then.

I'm not familiar with the Stark internals...
 
#6 ·
Thread is 10 years old, should open a new one but if your gun is dumping all the gas out the barrel that usually means the gas pressure is to low for the system to operate. It can also indicate damage to the mechanism, usually a crack or damaged part somewhere near the hammer than opens the valve on the magazine, or that the slide / mech is gunked up and needs to be cleaned.

First make sure you are filling your magazines correctly. If your gun is Green Gas, hold the magazine with the fill port facing upwards, press the gas canister down onto the fill port, and wait until you cannot hear any gas transferring. Usually ~7-10 seconds. Try using a new can of Green Gas. If you are using CO2, check for leaks around the barb that pierces the top of the bulb when installed into the magazine.

Second, inspect the valve on your magazine. You are looking for damage, wear, etc. Make sure it is threaded in properly. also check the seal on the top of the magazine, make sure it's not damaged.

Third - if it's cold where you are, try heating the gun and magazine up to body temperature - most gas blow back designs experience issues in the cold due to the reduced pressure. You can try 'winter' gas if this appears to be the case, it is a higher pressure option for Green Gas guns.

Finally, look for an exploded diagram of your gun and watch a few videos on how to disassemble it on YouTube etc - you will most likely need to take it apart and try to find the problem. I've seen cracked hammers, bend pins, etc, cause this - or if you are lucky, maybe just some dirt in the mech preventing it from resetting properly.
 
#7 ·
Make sure your temp gradient is at least 15C between mag and fill tank...it not...your are filling it wrong.
 
#8 ·
60 degree difference between gas can and mag? I didn’t know it was so much.. thought I’d read 20 degrees a few times. this summer I couldn’t get my VFC V3 to function properly on a hot day over 90F feeling my mags correctly lol it was like the pressure was so high against the release valve the gun couldn’t hit it hard enough.
 
#9 ·
15C variance is around ~27 degrees.

And you can move the temp gradient with appropriate manipulation of the ideal gas law.
 
#11 ·
Most likely not enough of a transfer gradient in the temperature. You need to Chill the Magazine considerably before you can fill it.

And it comes down to plain physics in the ideal gas law of PV=nRT. Gas won't move in the liquid state from vessels with near the same pressures.