How is the lock bolt hole drilled and tapped so it lines up correctly?
The lock is clamped in place on the stock, then drilled through the stock, washer, and lock bolster using a bit sized to the existing hole, followed by a tap-sized bit and a tap. Doing this with the lock installed in the stock keeps everything aligned; drilling the lock off the gun or on a drill press is not recommended because the hole is not perpendicular to the plate.