if it shoots like you say 1rst 3 rounds is 1 inch apart at 100 and worst case was that was a 3 inch spread and a 100 yd is what you want it's still a deer killer!
Also George I dont think bullet oal is going to bring your groups down from 2-3 inches to 1 moa the comparator is for people wanting to achieve bug hole five shot groups. measuring oal with a calliper wont vary more than I say 10-30 thousands! I use the Sinclair comparator and I have found that with premium match bullets it want vary even that much. I still think if you drop down to 80-95grain bullets it will shoot good again and at a 100 yds these bullets will drop deer dead. and if you shot all touching at 100 with the lighter bullets and with a 4 power scope it cant be you!
read this
http://www.gunsandammomag.com/classics/ct0504/