Whether the front screw is real tight or loose shouldn't affect POI.

One way to see if you are putting varible pressure on the barrel is to put the forarm piece on. Now without the screw in, are you able to move the front of the forearm off the gas port (peice you are screwing into). All the pressure (or most of it ) should be on the gas port. The rear of the forearm should be just barely touching the action. There should be pieces of metal there near the action that holds the forearm on. Let me know if this helped you.