When I was young I shot a lot of 1000 yard matches at Camp Perry, both Ohio matches and the Nationals. Time of flight is about 2 sconds and you need to be looking through your (defocussed) spotting scope to watch the mirage flow. That's how you dope the wind.
Today, at the Alliance Rifle Club about 1.5 hour South of Cleveland, we have about 10 firing points to 1000 yards.
When I shot, almost everyone used a 30-06 or, better still, a .300 H&H, with 190 grain Sierra Match Kings. F class had not yet been invented so we slung up and shot prone. I last shot there in 2015 but shot the 600 yard matches instead of 1000 yards.
.223s don't cut it around here at 1000 yards. You can't keep the bullets supersonic and when they transition to subsonic, usually at about 900 yards, there is an upset in direction.
I hope your daughter continues with this sport. It's fascinating.
I quit when i went to college but a few years later I went back abd shot the Leech (iron sight national championship). It's a 20-shot match. I had about 15 shots down with about 13 Vs (the V-ring was 20") when it suddenly occurred to me I might win the match. Well that kind of thinking is no good. The next shot was a 4 and after that i just didn't csre. I fired the rest right in the middle, though.
