Gee Shinbone, it's not just you that's getting tripped up by ''semantics and seat of the pants geometry". A lot of people on here seem to have no idea how gun barrels are put together. They aren't regulated. They aren't shot for POI. They are put together in a jig or fixture that is set up to give a convergence point somewhere from 30 to 40 yards depending on the maker and the gauge. That is just the center line of both bores crossing visually, not where two projectiles would cross because projectiles come in various weights and velocities. If you've got the money and can specify shot weight and velocity then gunmakers can produce barrels that will shoot anywhere you want them to. Lacking that they do the next best thing which is to line up the tubes visually. Sometimes things don't go so well and one barrel fires North and the other fires West. If the divergence isn't much it can sometimes be corrected by muzzle work but that's a bit hit or miss, pun intended.
