65BR
The reason I shoot ( or used to shoot, I don't hunt as avidly now) multiple shot groups is because in my experience there have been problems that don't show up in one or two shots at 100 yards. One example is a 270 and a 7 magnum that i had at the same time. Both would shoot excellent groups at 100 yards, but at 300 yards the 270 would shoot 6 to 8 inch groups and the 7 magnum would shoot 3 inch groups. And I took advantage of the accuracy of that 7 magnum at least a couple of times that I can remember.
Another example of the reason for multiple groups is a 25/06 residing in the gun safe behind me. For years it shot very well and took a lot of deer. And now, at the range, it will shoot the first 2 or 3 shots and sometimes the first 10 into good groups. But, it will spray about 30 % of it's rounds over a 6 or 8 inch pattern at 100 yards. Don't know yet what that problem is, but have determined it's not the scope. Those are the kind of problems I want to find at the range and not when I am trying to kill a buck that is 400 yards away and looking to change zip codes right away.

Fred