This has been discussed many times in the past. True, the originol 6PPC case called for a 1/16 inch flashhole. But Lapua actually drills them with a 1.5 mm drill, (.059), hence the reason that a 1/16 drill witll usually remove a small amount of metal.
That being said, I have had lot numbers of 220 Russian Cases where the 1/16 drill did not remove anything, and other lots where they were pretty small, resulting in the drill cutting quite a bit out. I have no explanation for this. I have been using the same little .062 drill for years.
I do not run the drill in to make them bigger, just to get them all the same size, and they do vary, even cases coming out of the same box. This could be due to Lapua starting a run with a drill, (or drills), and as they get dull, they cut a tad smaller, but they do not change them untill some problem occurs. .........jackie