Let’s start by saying I’m by no means an Airgun tech, I’m more of a novice mild tinkerer. I haven’t really been active in the Airgun realm for a couple years now, other than dealing with a few ground hogs in the garden. I recently had shoulder surgery and now have plenty of time on my hands. So I broke out the old gladiator mk2 for some plinking from the picnic table to fight the boredom. Here is my first red flag, the gun is acting as if it’s not regulated, like poi shift as pressure is dropping. And I know I’m well within the “on reg” pressure range. When I went to fill it (first full 3000 psi fill in probably a year and a half or so) it started leaking at about 2500 or so. It’ll go from 3000 to 2500 ish in about 5-10 min the stays at 2500. I couldn’t tell where the leak was coming from so I removed the action from the stock. Normally you back off the front air cylinder a few turns, which closes the valve for that cylinder. Then remove the back cylinder with a puff of air and both cylinders stay charged and the action itself will continue to hold pressure because of the reg. Correct me please if I’m wrong so far. Upon removing the rear cylinder the front cylinder completely bled off as well as the pressure in the action. The shot string falling off and the pressure bleeding out of the front cylinder and the action leads me to believe the problem is hopefully as simple as a bad o ring on the reg or something. I found a few videos from Ernest Rowe on how to pretty much disassemble the whole gun I’m just looking for some reassurance that I’m heading in the right direction. Any help or advice is appreciated thanks guys.