get a cheap drill press from harbor freight or pawn shop, and a drill press vice large enough for 1/2 inch blocks of wood and stock and barrel.. measure four times and drill once.. when you do the barrel pins clamp vice down where
it hits pin exactly where you want it with barrel on fixed end of vice under pressure without stock.. .. then put stock properly mounted below on movable jaw and clamp it together and drill bit will go exactly where you clamped vice..make sure gun is square so hole is strait. the tiny 1/16 patch will be unnoticible when you fall down one day with the gun a put a 2 inch scratch in the stock, :hmm: you have t build a gun to find out 3/4 of the pitfalls.. the other 1/4 will be on the next.. .. dave..