pin point the leak first, use soapy water, if you suspect the fill port leaking, try putting some silicone oil in the probe and hose and fill the gun with air, it may be the o-ring needs lubrication, if it still leaks, replace the fill port o-ring, to test the poppet, remove the shroud and put a balloon or a plastic baggie over the end of the barrel, wrap a rubber band around it to seal good, make sure the bolt is closed, if the balloon fills up with air then the poppet is leaking and needs service or replacement, also check the regulator bleed port for leaks, use soapy water for leak testing, just make sure to wipe it off good after testing, if the regulator is leaking, replace all O-rings, also check the seal on the bottle neck with soapy water, if it is leaking replace the O-ring, Use silicone oil or silicone grease on all O-rings you are replacing, lube both O-ring and surface O-ring contacts.
good luck
BTW, to remove the shroud, use a hex wrench or a screw driver the size of the hole at the threaded muzzle end of the shroud.
