Here in the UK there is a discipline called Match Rifle. The rules are .308W only, scopes allowed with a rest but no back bags and the rifle cant touch the rest - it lays on the hand which is supported by the rest. A bit like sling shooting but with a rest instead of a sling - although some shooters use both. The target is a 24in bull with 14.4in x ring and the ranges shot are generally 1000, 1100 and 1200 yards. Where ranges permit upto 1500 yards. Course of fire generally 2 sighters and 15 or 20 to count. So max score 75.15. Plenty of possible at 1200 have been recorded with say 13x - although a good score at 1200 considered 2 be perhaps iro 73 with 10x or so, dependent on the conditions. Load wise, 215 Bergers are popular, mollied, seated long with circa 49 grains Reloder 17 or similar. Velocities with 215 grainers (32 or 34 in bores, 9 or 10 twist) run north of 2700 fps and many iro 2750fps. The 200.20x Bergers regularly pushed 2800fps out of suitably chambered rifles. Case life with Lapua cases about 5 before the pockets loosen. That's with about 50 to 100 thou of bullet in the case neck, mollied, full .308 bore (not tight palma type bore) and 32 to 34 in barrel. I would think such loads would make it to 1800 yards though at Sea Level, +15 Deg C and standard pressure, they fall through sonic at 1500 yards or so and are trans sonic 1300 or so but comfortably above M1.2 at 1200. All the above just for interest sake from the UK.