The "more advanced" test is dangerous, so listen closely...
First... And MOST important, have someone standing by to help you get you finger back out of your marker by removing the air supply.
Second... Do *NOT* have a battery in the marker. We are not firing it, we are simply looking for leaks.
Third... Air up the marker. To conduct this test read the entire paragraph and then follow these steps.. Place your finger into the breech and cover the tip of the bolt.
Results and what they mean:
If you get a pressure build up, and the bolt does *NOT* move forward, then you have a leaking poppet.
If you get pressure build up and the bolt moves forward then you have a leak in the #25 oring. As a note, this will happen quickly, and you will likely get your finger pinched. It *WILL* be painful, so have a plan to extricate your digit. (I didn't the first time, I was alone, and it took nearly 5 minutes worth of rather painful work to remove the tank, a 16th of a turn at a time.)
If you get no pressure, and the leak continues, then the #25 orings are suspect, as are the 017 (I think) on the outside of the bolt or the #28 orings on the bolt guide.