Looking at the experience you have with IMR 8208 and Speer 87 gr bullet, I would look at the rifle.
Several Savage 99's have came thru my hands and they all would group 2" or less with factory 100 grain loads and 87-90 grain handloads. The worst one would group 2 1/2" at 100 yards.
I have a Ruger 77 tanger that likes 36 gr of IMR 8208 with the Sierra 90 gr HPBT for MOA groups, but H4895 does better and continues to be my go to powder in this rifle. I started at 32 grains.
