You were chasing the bull when you state you fine tuned and verified that changes in the POI with shots...this can lead to lots of mental fatique! Remember when assessing accuracy problems you need to formulate a check list and change one thing at time. If things check out you return them to normal and move on to the next item on your list. Many possibilities, shooter, ammo, scope and possibly gun it is a process that can easily be rushed but shouldn't be! Head back with 1 type of ammo and a cool head/fresh start to see what happens. Like said slow down and let that barrel cool bewteen groups, shoot a 3 shot intial group and don't touch the scope caps - assess the group first then react appropriately. I'd do a visual check of the scope and mounts to ensure everything is good here before heading back.

Best of Luck

Watch pressure placed on the barrel. This is a common mistake off uncoventional rests and shooting sticks.