Check the diameter of the firing pin at the tip and the firing pin hole in the bolt head. Could be you have too much clearance between the two. Look closely at your cratered but not blanked primers and see if there is a raised rim of material that tried to flow between the firing pin and bolt head. If so and your clearance is more than .002, have the bolt head bushed, or buy a few firing pins from Savage and cherry pick the largest diameter of the bunch.

You may be overpressure on your loads, or you may just have a poor fit between the bolt head and firing pin.