Reduce the powder charge to 70 grains, and 75 grains, to see how it pattern with them.
Also, try Jim Rackham's suggestion of using ONLY OS cards. 4 cards instead of the OP wad, and cushion wad, then shot, then 2 OS cards. Use and awl to poke an off center hole in each card, and don't line the holes up with each other.
Jim puts a dab, or ball of lube between his 3rd and 4th cards under the shot, to lube the barrel. I prefer to run a Lubed cleaning patch down the barrel when I am seating the 2 OS card on top of the shot. This lubes the barrel in front of the shot, allowing the shot to slide Over the barrel, rather than rub flats in the lead pellets against the steel barrel. I don't want the lead deposits to remove, and I don't want flats on the pellets which drop those pellets out of my pattern. Of course, my technique will also lube the barrel to keep residue soft. Oh, those lead streaks reek havoc with your subsequent patterns, which is the other reason I want my shot to get out of the barrel in as round a shape as possible.
I use FFg powder rather than FFFg because I want the lower chamber pressure behind those pellets, so they are not misshapen by a sharp ignition and faster velocity. The weight of the pellet is what is going to kill the bird, not the small difference in velocity.