If you want a rifle that will shoot in short range BR group and score, and then one that will shoot f-class to 600 yards you may want to get two stocks. But I have to say that there is no "one guns does all" set-up anymore. The 6mmbr is a great chambering, and will allow you to reach the yardages you listed, but is better suited for the longer set of ranges 300-1000 (and some would argue about the 1000yd part) If you check equipment lists on 600-1000yd shooting you won't find anyone who takes their gun to a short range match. Highly specialized pieces of equipment.
If you are looking to enjoy shooting at paper at the range non-competitively, and then drop some prairie dogs at mid-range, I would look into the mcmillan f-class stock or any of their live varmint stocks. The Tooley MBR would be a great bench/varmint stock, but for a more portable version the remington varmint stock might be the ticket.
The reason I say this is I don't know how comfortable you'd be on the ground with a stock specifically designed for short range BR, and vice versa it would hard to make weight in the 1-300 yd BR classes with a typical f-class stock.
What sort of shooting, aside from the ranges you mentioned, are you hoping to shoot (plinking at the range, competition, varminting)? This will help you get the best information you can.
Mike