OK - in order to squeeze out the maximum amount of accuracy possible of a 10/22 build, I would think that the goal would be to achieve a tight barrel to receiver fit. I'm sure that a 11/16" drill bit for the barrel hole works - but - from what I'm reading on this thread there is the possibility that the barrel hole to barrel interface can be a little loose.
With this in mind, the Gen 8 Drill Fixture on the following website has you use a 1/4" punch to mark the barrel hole center location on the face of the receiver. You do not use the Barrel Hole Locator as a drill jig.
Rather, it sounds like you make your locating 1/4" punched "center mark", and then go straight to the 11/16" drill bit, and bore away on the front of the receiver - using (1) drill to go from "nothing" to your barrel hole. The instructions do not mention about starting out with a small drill bit, and from there working your way up to an 11/16" drill bit...
Link showing Gen 8 Jig (3rd picture down from the top): http://www.ruger1022receiver.com/Dri...structions.htm
With the method (ABOVE) in mind, could a person go another direction - for instance; you punch your centering mark with the 1/4" punch, then using that centering mark start the barrel hole with a series of small drill bits, work your way up to a 21/32" "Silver and Deming" type drill bit, and finish the barrel hole with a 11/64" High Speed Steel (HSS) "chucking" type reamer or?
One thing I learned from AK builds/BP's is that there is more than one way to hit your goal - some ways being even easier, or not much more work, and in the end offering up better results.