Into the grooves

[Powderfinger61]

Here is something that puzzles me that I can't seem to grasp.

I understand the OAL of a bullet measured at the ogive and 10 thou off the lands, but how do you measure 10 Thou into the lands? To me, all you would be doing is pushing the bullet into the neck just a bit further.

What am i missing here?

 

[308BAR]

Considering the10 thous jam pressure doesn't exceed the neck tension you put on your case to hold the bullet in the case. The bullet will not seat any further into your case. "soft seating" provide just enough neck tension to hold the bullet, this method allows the bullet to be seated further when jammed into the lands.