Gamo Big Bore

So after reading about this Gamo TC35L I finally decided to buy one. I tried filling the tank with my Benjamin traveler compressor. The carbon fiber bottle should be fillable to a maximum of 250 bar, however, When the compressor gauge hits 220 bar, I hear a pinging click noise in the area where the tank pressure gauge and fill probe are located And the compressor gauge needle drops down to about 180 bar and then continually increases back up to 220 again kicking out and dropping down to about 180 again. This will continue to occur over and over not going past the 220 bar mark. The gage on the bottle reaches 200 bar but something seems to be preventing it from going past that. Has anyone else had similar issues?
 
jorgo.. thats the fpe for the tc35 the short gun,,, mine is the tc35L its much longer .. i have not tuned it.. out of the box with a 205gr slug in getting 284 fpe.. there is not a whole lot of info online about the tc35L most people dont even know gamo made it.. airgun pro-shop is the only place i know selling it and they have a short video on youtube about it
 
The new L rifles are also the ones that Evike is selling, though they don't even know it. I thought I was getting a standard TC45, with the fore grip shroud, reg barrel, then moderator. I ended up with the 45L, which is like yours the full length unvented shroud. I called Gamo, it seems the full shroud version is the new one and nobody (not even they) have updated photos anyplace.