My drillpress has a reinforced sheet of 3/4" X 2' x 4' plywood bolted to the table. The bbl/stock assembly is clamped in an accurate vise w/ the top bbl flat against the permanent jaw. The vise is at the breech end and a parallel is midway towards the muzzle. At each pin location, 2 parallel clamps are used and the 1/16 drill picks up the center punch and the hole is drilled through. A length of music wire is pushed into the hole and the clamps are moved to the next pin location etc., until all the holes are drilled. This same procedure is also used for the RR pipes. For drilling a precarve w/ curved sides, a small flat is chiseled , center punched and drilled. The flat is removed while shaping. Have found that this procedure is fast and accurate and all the holes are drilled in one setup. ....even w/ webs of 3/32"-1/8".. Lock bolts are also drilled this way.....Fred