I used the drill jig and it took too long. So went back to the way I've done it since first starting to build.
Have a drillpress that has a large sheet of reinforced 3/4" thick plywood . The bbl/stk ass'y is clamped in a very accurate vise w/ the top bbl flat against the permanent jaw. A parallel towards the muzzle keeps things horizontal. A 1/16 drill is used along w/ 1/16 dia music wire.
2 parallel clamps are used on both sides of the first bbl lug and after drilling straight through, a length of music wire is pushed into the hole. The clamps are then moved to the next bbl lug and the hole is drilled. This is repeated until the 4 holes are drilled.
The large plywood sheet enables all 4 holes to be drilled in one setup and takes approx. 15 mins at the most.
Later on the same setup and procedure is done when drilling the RR pipe holes except the pipe itself is clamped against the wood..
The 1/16 drill is run at 1500 RPM and cleared of chips quite often
The Bucks County LRs that I mainly build have webs of 1/16 at the breech and 5/32" at the muzzle so very accurate locations for the lug and pipe pin holes are a necessity......Fred