Usual twist rate for .308 Win is 1/12 or 1/10. You can measure your barrel with a tight patch and a marked cleaning rod to determine exactly what yours is. The M99 Savage is a rear locking action,so best to avoid max loads. Max loads are better handled in a front locking bolt gun like the M700 Rem or M70 Win.Generally excellent accuracy can be found at less than max velocity. The .308 Win handles standard hunting bullets of 150,165,and 180 gr. Best to shoot yours to determine what works best in it. The performance baseline powder for .308 Win handloads is IMR 4895. Others that work well incl IMR 3031, IMR 4064, IMR 4320, W748, H4895, Varget, and BLC2.