perhaps a dumb question.... How exactly do you measure group size???

[sgt_murf]

The most accurate way is to measure far side to far side of the two widest seperation holes, then deduct the diameter of the bullet. Thus....

Far side to far side equals 1.264 inches. Deduct the diameter of the bullet, 1.264-.264, and you have a 1 inch group.

LRRPF52's method is also accurate, but sometimes it is impossible to find the inside edge if two shots overlap.

Center to Center is impossible, because you are simply guessing where the actual center is, AND having to guess twice in the same measurement!

+1 Use the same method except
On Service Rifle / Competition / Tactical weapons the groups are 20 shots using the furthest distance between the groups gives the best data.
On hunting arms usually 5 shot groups give the best as one usually does not fire more than that hunting (key word is usually)
Cuz when the load is dialed in the wind and elev side are pretty much the same unles the wind is blowing