Leaking mag!!!
 

How do you fix a leaking mag thats leaking from the valve???

Which valve? Get some silicon oil from the hobby shop (RC Shock Oil, 10 or 15 weight) and put a couple drops inthe valve, then press and release it a couple dozen times so the oil can drip in and coat everything rubber.

And, never keep your mags empty, always keep at least a bit of gas in them.

what if its leaking from where you fill it?

Theres still a rubber inside, ud have to remove the fill nozzel and apply some oil manually.

ok thanks

With any gas guns oil is your very best best friend.