"stay good" I presume you mean stay supersonic - for the 700P (assuming the 26" barrel, not the 20" LTR) the 175s Federal Gold Medal Match can go at least to 1,000 yards. Some say teh maximum effective range of the .308 is 800 yards - others say 1,000 yards. I've shot it out past 1,000 yards, and could hit what I aimed at. I suspect Mel awnd some of the other members here have taken it out past 1,100 yards - but I'll let themspeak on this for themselves.
The 300 WM shoots the same size bullets (30 caliber) as the .308, it just does so MUCH faster, whcih allows you - the shooter - to stretch the maximum effective range to at least 1,200 yards.
JeffVN