Bart - Don't feed the troll!
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"When Mr. Stecker says a meaningful change is 0.002" to 0.005", I believe he means that is the limit of useful resolution of seating depth adjustments. In other words, that's the kind of round-to-round variation in ogive distance off the lands you normally find after seating bullets, so attempting to make adjustments any smaller for any purpose whatsoever is pointless."
Absolutely correct, amen. Few custom barreled target rifles are sensitive to such tiny seating differences and no factory guns at all.
All good loads have a 'window' of good accuracy where a few tenths of a grain or powder or a few thou of OAL won't make any noticable difference. Charging or seating at the ragged edge can be sensitive to changes in the wrong dirrection but, if we load in the middle of the window, small differences in a properly developed load should make no difference.
Book OAL is not a "recommendation" and it's no more a law than their powder listings; it's just what the book makers used for their firearms and can be expected to be safe in any properly chambered rig. Finding our best OAL is just as much a part of the game as finding the best powder charge.
Seating bullets long in a rifle
will increase starting and peak pressure but that pressure increase will rarely have much useful effect on velocity. Seating deeper and using more powder, or a different powder, does that.