A number of folks have been successful with the 6.5 Grendel out to 600 yards in F-Class competitions. They are good shooters and have learned that only the best beat them at 1,000 but the lower muzzle velocity means that excellent shooters with cartridges like the 7 WSM will beat them at 1000 yards on windy days.

That said, the paper ballistics would suggest a heavy VLD in the .243 or the AI version will do extremely well. For example, the Hornady 105 gr A-Max at 3,000 fps gives slightly less drift than the 190gr 300 Win Mag Berger VLD at both 600 yards and 1000 yards. The recoil is more like that of ... (you guessed it!!) ... the .243 Winchester than the 300 Win Mag or the .308 Winchester.

You will want to use a barrel with a faster than standard twist, however.