First off...screw in your velocity adjuster clockwise til it stops.
Now...back it out two full turns.
This will seat the poppet properly.
Next....screw in your tank, and make sure that the tank is screwed in completely.
Thats why your leaking down the barrel, and the pressure is dropping.
If the pressure keeps climbing past 200 psi, youll need to remove the regulator adjustment screw, and retune the regulator.
Review the disassembly/reassembly videos found in the stickies.
It will guide you through the necessary steps to retune the regulator.