WE gas leak

[spitfireace1]

hi can anybody help please i have a WE luger and think the gas
is leaking i can only get 1or 1.5 mags per fill
and gas seems to vent from top of gun.

1, can mag be fixed
2, is tanaka mag compatible with WE luger
3, WE sometimes double feeds
4, how do you know when gas in mag is full
dosnt overflow.

has anybody else had similar problems
PLEASE help please pm me.
in advance
many thanks