I know this is a old post but I found when pumping my Umarex Gauntlet Gen 2 in 30 cal that the valve doesn't start to fully seat until you hit around 1,000 PSI and 1,200 PSI. The more air that's put into the 393cc tank past 1,000 - 1,200 PSI the better the seat gets. This is why I'm sure 95% of...