Minimum bullet seating Depth?

I have been reloading some light weight bullets in my .308 for varmint hunting.
One of the problems with light weight bullets is their short length and the large jump they produce besides their poor ballistic coefficient.
I have been told over the years that the bullet should be seated at least on caliber worth of length down into the neck. I'm curious if this is a must or what is the minimum depth?
I would be interested in others opinions on this matter.
What is the minimum depth that a bullet should be seated into the neck?

In most cases the minimum is what ever it takes to hold the bullet long enough to chamber and shoot , for a bench gun that is loaded one at a time and exposed to little abuse the number can be very small , while a round that is to be used for a western elk hunting trip will need a much deeper seating . stimpy

I was under the impression that in order to get a good powder burn there should be a certain amount of bullet tention so proper pressures should build before bullet release.
Can anyone recommend a technical source to call about this issue like Sierra or Nosler.

You may be thinking of neck tension. I've seated bullet's 1/16" in the case before.