its not a dumb question, I was having the same problem. what I did was measured the length of 25 bullets with a pair of digital calipers figured a average length then took a bullet that was the same length as the average, adjusted my bullet seater with it and then just went with it, My COL still varies but atleast I know they are all seated the same. I more or less forgot about worrying about the .004 to .007 COL variances I was having, since I cant see any evidence in the accuracy to determine that the variances is affecting my accuracy I'm no longer worrying about it.