I don't have my C7 PAM handy, so correct me if I'm wrong. But I believe that in order to get a top score on any C7 PWT the minimum requirement is a 100mm or smaller grouping with a C79 sight, prone, unsupported, at a figure 11 on a 4 ft screen. With issue irons I believe it is/was 150mm. I believe the max allowable size is 200mm with the optics, and 250 with irons, but that only gets you half points.
Correct me if I'm wrong again, but any shooting done beyond 100m is considered practical and any hit is counted as a point. I've only ever seen groups measured at the 100m point.
Then again, we are using full length barrels. I've seen guys score under 1 inch with a C7A2 from the 100m point on a few occasions. I average about 1.5 to 2 inches.