my co2 magazine wont let the co2 bottle out

[Biz]

I had recently bought a $60 gas nbb pistol off a friend for $25 and it came with co2 canisters and a holster so I wasnt going to turn down that deal, but I come to find out after a day of airsofting the co2 had ran out and now when I use my allen wrench to open the bottom to get the co2 out, it wont budge, the allen wrench just goes from groove to groove but it fits very very tight and when I turn it, it just doesnt budge....I'v heard that if the co2 is empty some mags wont open or some shit....but I am not to sure what the problem is. Does anyone have any tips or tricks on how to get magazine open.....without breaking the magazine. Thanks! ;D

[a1 (Babez)]

It would help to know what kind of Co2 gun it is, so maybe someone with the same gun or with a similiar experiance could help you.