Re: question about bullets seated out past neck shoulder junction
I personally don't see a problem with seating out the bullets that far. And you're right that with sufficent neck tension, the bullets should stay put. The only exception to this situation would be if the bullets in the magazine weren't getting rotated out of the magazine. Meaning, after a shot a new bullet would be placed on top, with this happening over and over in the course of a day of hunting, the bullets can back themselves out of the case. I've seen it happen with a .30-06 and a 165g bullet. Some of the others also grew and when chambered, the bullets got stuck in the rifleings.
After seeing this, I make a mental note to "rotate the bullets" every so often so that this doesn't happen. This is one "argument" for crimping bullets, (which I'm not a fan of).
My reloading mentor (NRA Certified reloading instructor) said that the rule of thumb was to seat a minimum of 1 caliber, for example a .308 was seated atleas 0.308" and so on. He also told me this was a "loose" rule and what ever worked would be OK. There is no other danger except fitting in the Magazine and the above mention situation. Try it. See what happens.