Originally Posted by Sako7STW
I have no idea yet. The 168 Bergers I am running around 3000-3200. I have tried H-1000 and RL-22 on Fed 215M's. Best group so far is 4.5" at 100 yards. I am actually using currently the 127 gr. Groove Bullet (some old timers on here might remember them) that are no longer made. They are screaming out at 3800 FPS and will still print a cloverleaf at 200yrds. I have 17 of these left so i need to find a new bullet.
My Sako has a 26" bbl and a 9.5 twist
My guess would be that you don't have a fast enough twist rate for the heavier bullets and need to back down to a Max of 160gr's.
You might want to give the 150gr accubond, Scirocco, or the 154gr Hornady Interlock a try.
The long/heavy monometal bullets require a higher RPM to stabilize than similar jacketed bullets in order to stabilize and RPM is a function of velocity and twist rate.