Bad gas?

[Silver_surfer]

I've been having no end of performance problems with my ASG CZ75 sp01 shadow. 

 

Not cycling fully - leaving the chamber unloaded and only half cocking the hammer. I though I was suffering from cool down (after 4 shots) 

 

I assumed it it was just weather - then that got better and the gun did not. I would carry the mag in my pocket to try and warm it up and it would work for a while. 

 

Then on my last skirmish one of my squaddies refilled his G18 mags from my gas can (nuprol red that I only bought Christmas) and he suffered the same issue. His extended worked fine (filled from his gas can) 

 

So is it possible that my gas is bad? 

 

Probably worth trying a different can next outing.