I recently purchased 300 new Win 30-06 cases for my '06 Ackley. I culled them via a Sinclair Mic-4 neck wall thickness gage http://www.sinclairintl.com/cgi-bin/category.cgi?category=REMTCG&item=MIC-4&type=store I was able to cull out 55 cases which had a neck thickness variation of .00075" or less. When reading Glen Zediker's book on reloading he suggests neck turning only the best cases to get them as close to zero runout as possible. I'm dying to turn them but wonder if my chamber's neck to too generous to really make a difference. The case necks are averaging .0013" thick. My fired case necks are running .341". Sized via my Lee Collet neck die they run .332". A .009" difference. .308" bullet diameter .026" neck thickness .013 x 2 .334" total What do you think of these numbers and whether or not I should turn my necks?