I've used some of the heavier bullets 65 and up out of an AR 223 AI for some longer ranges. The best performer i can remember was the 69 Nosler Comp. and it gave decent terminal ballistics out to 550 yds. (1 coyote shot at that range only).
I actually connected on a coyote at 700-some yds. once with the 75 A-Max (shot i shouldn't have taken), and it yelped and took off running--God knows where i hit it. Never had another long-range opportunity with that bullet--will probably try it again soon.
I had very good results with the 65 JLK Low Drag out to 500 yds., and will probaby continue to use this bullet when i'm not using the 75 A-Max.
If you're using an AR try and get ahold of the old DPMS VLD magazine so u can use the bullets seated out further.
