You have said that the barrel is fully free floated. You have also commmented on the bedding issue...
This may be sound stupid and way too easy a fix, but it is well worth the $ and time to try it (it''ll cost you almost zero for both).
Try placing a tiny amount of upward pressure near the end of the stock between the barrel channel and the barrel. It might be a small piece of credit card super glued in place, a piece of wire... just someting that won't deform or move.......
I've had a few guns that wouldn't respond to anything else when I was trying to wring out the last 1/2" of accuracy.
It can be maddening when bedding, crown, trigger and proper rest are all accounted for and the damn gun still moves it's point of impact around within five shots.
Good luck...