Marrakai
Something else you might try.
When shooting at 50 yards 89 grains of RL 15 shot a little bit better in my 450 No2 than 88 gr. However at 100 yards 89 grains hit a little too low. I tried 88 grains and VOILA the bullets hit to the sights. The slightly longer barrel time raised the point of impact. A slight increase in powder, if there are no pressure signs, might make you hit lower on the target. Of course the opposite could also ne true, each rifle is a law into itself.