The Brits are deadly at that range and more with their 308s and train for it. I am not good much beyond 400 yards with my 45 and wouldn't even attempt 1000 yards with any less than my 30-06.
You’re good at 400 yards with a .45?
We have our own who train for this. But those who do train and become proficient are very few amongst the entire military.
308's and .06's are fairly comparable rounds. Though match grade can reach out to 1000 yds, I'd take an 338 lapua any day at this range. It has a flatter trajectory, less drift in any condition, and greater impact power.
Sub 1000 yd, the 308 is hard to beat, especially from 600 yds down.
Most police snipers (who are generally former military trained) use 308's and can repeatedly hit a nickel at 100 yds.
How many cops need to worry about targets much beyond 200 yds?