I have just filled my Air Arms 410 and I have noticed that the guage on the the rifle stock only seems to move mid way between 150 bar marker and the 200 bar marker. The guage on the bottle clearly reads 190 bar of pressure. i.e the correct filling pressure. Is this normal

Also I have just realised the importance of using a bonded seal when connecting the brass air arms connector. I couldn't work out why I was loosing air on the fill. I stuck a temporary rubber one on there and hey Presto sorted.