Pavomesa - It is possible as group size is measured center to center. My method is to measure the outside edges of the bullet holes and then subtract one bullet diameter. In this case, to achieve a .25" group with a 45-70 the group would have had to measure a total of 0.708" less .458" = .25". To say that this is remarkable accuracy at 100 yds out of a Marlin lever action 45-70 is an understatement. These bullets would have almost had to have gone through the same hole.