I have an umarex g2 that has a slow leak... I can fill it up the night before I got to shoot it and by the morning it will be down to 1k psi. This did not start until I degassed it and when it was degassing the plug that fits over the fill plug popped off. Was wondering if anyone had any ideas whats going on with my gun maybe the fill valve now has a slow leak? any info would help.