Ideas on This XValve Issue?

[A-Tach-One]

Well, I have been having a problem with my first shot being ridiculously hot. The valve seems to be building pressure as it sits for a few seconds. First shot will be lets say 350 fps and all shots after are in the 225 range. Also as the valve sits for a few seconds it begins to leak out the back. If I chrono my first shot at 280, then all shots after are under 200 fps or so. Any ideas guys? Thanks

[Dayspring]

Take out the reg pin, clean & re-lube it. If that doesn't fix it, replace that & the regseat oring.

[A-Tach-One]

Take out the reg pin, clean & re-lube it. If that doesn't fix it, replace that & the regseat oring.

Great, I will try it. I'll let you know thanks.

[ThePixelGuru]

What causes that is most likely a little piece of junk stuck in the reg. It holds the reg open so that it never seals and never stops filling, which is why it constantly gains pressure and thus velocity, and eventually it vents gas out the rear to avoid becoming dangerous.