I got a new to me Mag with an X-valve and it is acting a little funny, but only for the first shot after it sits for a little bit, 10min or so. The valve has an RT on/off and has been oiled.
When I gas it up and let it sit the marker won't fire for the first shot. I pull the trigger and hold it back and after a few seconds I hear air go down the barrel then the bolt reset. At that point it is good to go and shoots perfectly. There is no leak before or after.
Is it an on/off issue, wrong sizer, powertube o-ring.