KWC Desert Eagle CO2 with Green Gas mags

[MassPwnage]

Alright so i recently purchased green gas mags for my CO2 Desert Eagle in order to drop the fps to CQB arena standards (320 FPS), now the site i bought them from advertised they would drop it between 300 -330 FPS but when I chrono'd them i was getting FPS of around 360-370! Now with the normal CO2 mags it shoots around 400FPS so im not sure if i did something wrong,would overfilling the mag cause something like this?
Any suggestions to make it drop lower? Because the only thing I can think of is reducing the hop up
Thanks

[Bellerophon]

What is the temperature you're testing these at? At higher temperatures, compressed gas expands more forcefully, potentially causing your gun to shoot hot. The advertized temperature was probably measured at 20C. If nothing else works, you can use duster gas, but it might not be strong enough to cycle the slide of a big heavy pistol like yours.

[MassPwnage]

Originally Posted by Bellerophon

What is the temperature you're testing these at? At higher temperatures, compressed gas expands more forcefully, potentially causing your gun to shoot hot. The advertized temperature was probably measured at 20C. If nothing else works, you can use duster gas, but it might not be strong enough to cycle the slide of a big heavy pistol like yours.

Im not sure about the temperature of the gas but it is possible that it was warmer then 20C since i had the gas in a car for a while, ill give it another shot in a cooler environment and see what happens. Thanks!