I've shot my custom armalite ar-10 at 1000 yds just for fun. I use 175gr matchkings in front of varget. As long as there is no wind or very predictable wind it does ok. But throw in the horrible Kansas wind and it's a pain to try to keep bullets on steel.
When the winds decent I take mine to 1000. Used a lot of 168 amaxs and 155 scenars. Wind is a pain though. Now I've switched to 168 eldm and going to build a single shot load with 200+ gr bullets.
It's a factory rem mil spec. Avg group is <.5moa but at 1k my es isn't the greatest it usually opens around 9-10" with a cluster at 5-6" then one or two high or low opening up the group.
For years, those of us who competed in Palma, fired the .308 Win. loaded with the 155 gr. Sierra match bullet. These competitions stressed a Nascar attitude of everyone shooting the same ammunition basically. Open sights and 155 grain bullets still managed to shoot some fine targets at 1,000 yards.
Currently though, with the exception of International and National competitions, it's become an 'any bullet' type of competition, so the heavier, higher BC bullets are winning the day.
1ASSASSIN: 308, Not the newest, Not the fastest, Not the sleekest, BUT, it's still a good cartridge! And your rifle is a great example of a nice looking 'No Frills' Shooter!!!!!Who's barrel is that, & which profile??? Looks plenty heavy! Looks like a Great Rig, & Great Shooter too!!!! Idaho-5R
Using Reloder 17 and the 215 Berger, I was getting 2525 fps out of a SAAMI chambered 24" barrel, and at 2.945 it will fit in most short actions accept the remingtons, but you can get a wyatts box or AICS DBM and run them as a repeater. And with that performance, if you long throat a .308 and have a longer barrel I have heard many people getting 2650 with the 215. Definitely 1000 yard capable!!!
1ASSISSIN: like you I'm shooting the 168MK. HS Presision with a 1-10 twist and 24 inch barrel with a bors system. Under a half minute when I do my part.