Re: What is the best way to measure 3 shot groups on targets
Many years ago, I measured outside edge of two widest holes. After I started shooting benchrest, I began measuring wide spread, then deduct the bore diameter.
It doesn't matter which you use for your personal records. The important thing is to always use the same system, and keep good records. On the computer, I run a spread sheet for each gun. I record date, temp., wind, no. of shots, case, powder, primer, bullet, OAL, sizer bushing, trim length, group size and a few notes. It makes it easy to return to my records and find the best load.