When I’m seating bullets into new (unfired) factory-annealed .308 Win Lapua brass cases, for years I’ve noticed that, when seating the bullet (via a RCBS RockChucker single stage press using Redding Competition dies), approximately ~ 1 to 2 out of 20 (i.e. 5-10%) of all cases produce significantly reduced neck tension during the bullet seating process. The difference is a factor of several fold. Question: I haven’t isolated and chronographed those low-neck tension rounds. Should I? I realize that for the Sierra 175 grain Tipped Matchking bullet fired at 2,620 fps MV, a mere 20 fps MV deviation results in a significant difference in drop at 1,000 yards.