just got an fx2000 pcp airgun, seems good, but i bought it with about half pressure in the canister, just went to the gun maybe 18 hours later and it is flat as a pancake, is this very bad, i was told it held pressure. any ideas as to what might be causing this, the pressure gauge is missing from the stock could this be it? are there any seals that regularly go on pcp guns or the fx2000? any clues as to what it may be and how i will sort it?? cheers. jay