I bought a new carbon bottle (Tuxing 500 cc 300bar) from amazon and a FX Valve from UA. I screwed in the bottle to the gun and put air in it with my compressor, the guns gauge reads 175 bar and the compressor gauge reads 250 bar. I have used this compressor to fill my gun multiple time with the stock bottle on it and the 2 gauges have always been exact. I have a maverick VP. Am I missing something? as it seemed straight forward lube the O-ring and screw the valve into the bottle ad air.