Just curious if the stock pressure gauges on these guns are typically accurate or ever known to have problems? Only reason I ask is I went yesterday and had my SCUBA tank filled at my local fire department. I was standing right there and they got the tank to exactly 3000 PSI, with their sophisticated equipment. I assume given the nature of their job, their equipment and gauges are accurate. When I took it back home and topped my gun off the gauge on the gun only shows 2600 PSI. Didn't know if this is unheard of or not?