Where on earth did you get the idea doubles were built to some incredibly tight tolerances? Many are nicely built but there's nothing special about the fitting. I mean, even on the best guns the bores are finished near some pre-determined diameter, and are aligned to shoot in the same general direction. The well built gun is joined where most of the bearing surfaces fit, but not all. The stock is headed up well enough to avoid cracking, etc. Even the best guns are not perfect. They display excellent workmanship, not perfection.

John McCain is my war hero.