So seating the bullet too deep results in too high pressure, seating it too shallow makes it too long to cycle properly? It's pretty obvious when you're over length in a revolver, what about a bolt or lever action? Are there headspace problems if they're loaded too long or is it a cycling issue? Using .357 as an example, how profound are the velocity fluctuations between batches of minimum vs maximum seating depth. (I assume there's several things factored in here, I would accept answers like "A lot," or "not enough to worry about," or "doesn't really matter except for competition.") Can round nose be used in tube fed carbines?