Hi all.hope i am posting in the right section.new to LR and PS.been hunting a long time but never had to measure my groups.in the process of building my first PS rig(Tikka CTR)i went to the range with a new buddy i met at my local gun shop last week and he was kind enough to let me shoot his Savage rig.these were my 2 best groups at 100 yds.i watched a few videos and saw you use the micrometer to measure 2 holes furthest apart from both outter edges then subtract bullet diameter(we were shooting .308)i have 2 pics below.am i measuring correctly?