Mine also becomes very pellet fussy if i clean the barrel.
Also I tend to get a few shots low on fps between 200 and 190 bar. So I generally fill to 180 to be safe.
I know it can put in 8mm groups at 45 yards when I do my bit. I'm experimenting with pellet sizing to, still inconclusive
Weighing pellets makes a huge difference in the PT for me, more so than in my other guns.