Inlet the receiver. Mark the bottom of the receiver where the hole for the screw is with inletting black, and press the receiver straight into the stock. Mark the center of the hole that shows up in the black inside the stock inletting.
Set up stock with receiver under a drill press, with the barrel level and straight. Remover barreled receiver, center marked, levelled stock under the bit, and drill the hole.
Same with the rear tang screw, except it may be at an angle.
Most modern rifles with wood stocks use a pillar inset in the hole to stop the screw from compressing the wood.
I swear by Jupiter Optimus Maximus .... in the army of the consul Lucius Quinctius Cincinnatus and for 10 miles around it I will not steal anything worth more than a sestertius in any one day.