With all of the discussion on who makes the best brass, full size or neck size, and so forth, no one talks about an important variable: flash hole uniformity.
At the factory, flash holes are "punched" through. Depending on the age of the punch, etc, they are not all uniform. With fast burn flake powders it has been found that it is not that important. However, with Ball, it's another game. The ideal is 0.0810" on any large primer, rifle or pistol.
Buy two drills...#46 @ 0.0810" and a #44 @ 0.0860" Check all flash holes with these two. If the flash hole will not take the #46 @ 0.0810", drill it out with it, by hand. If it takes the #44 @ 0.086".....mash & discard. Anything 0.086" or larger allows too much Ball to sift into the primer area; or, if smaller, it is not hot enough for uniform burn. Factory specs are 0.0780" to 0.0820". Absolute Max. is #45 @ 0.0820"!
After making sure your flash hole is the right size, take a sharp, larger drill and go inside of the case to deburr the flash hole by hand. Something to think about!