I wouldn't fret 1/2 caliber deep seating. Yes, it seems wrong and it seems like the bullets will easily get knocked out of wack, but if the gun shoots the loads well don't mess with success.

A friend had a wildcat 6.5mm based on the 5.56R case in his contender that had at most 1/8" neck, so less than 1/2 caliber and it shot bughole groups.