I understand what you're saying, Joe, but when I think of a precision round I think in terms of "F" class or fullbore where you are going to be shooting up to 100 rounds prone during the course of the match. Shooting prone from a rest or a bipod is a punishing position with a heavy recoiling rifle (it's better shooting with a sling).
Shooting 1000 yd BR is a different matter and from the bench a 16.5 lb 300 WSM is quite manageable given the fewer number of shots fired and the better position for recoil absorption. Also, the shooting format really favours the round with the best wind bucking ability since, in the matches I've shot in anyway, you are in essence shooting blind. There are no spotters and you really have no idea where the last shot went relative to the rest of the group. In "F" class, you are able to make adjustments based on your previous shots and the conditions under which they were fired. If you know your rifle and it's wind bucking ability (or not) and are able to successfully read the flags, you are able to compensate accordingly and make a good shot. Within reason, the ballistic capability of the round is unimportant. The ability of the shooter to utilize fully the accuracy of the outfit trumps everything else. This is why I say the best precision rounds are those which;
(a) are capable of providing the best accuracy and
(b) punish the shooter the least making (a) possible.
Now, one thing that has to be mentioned in favour of the WSM (or anything bigger than the 308, for that matter) is that the 308 is just barely a 1000 yd cartridge due to velocity limits while larger cartridges shooting heavier bullets do it easily. Regards, Bill.