Thanks for all the input.
Brent; I've got a Gre'-Tan Rifles XP in 6.5-284 Win. Burris 3-12XLER with Ballistic Plex reticle zeroed to 600 yds. with comeups calculated to 1000, with the 129 gr. Hornady SST @ 2900 out of the 15" barrel. Believe it or not i actually took a coyote @ 906 yds. a month or so ago, but i think i was real lucky to have dropped him on the spot, as the bullet exited the spine. I bet if i'd have hit him thru the lungs, he would have gotten away and I'd have never found him. But the info presented here has been a big help, and i think i'm going to try the 120 Nosler, and maybe the A-Max. Hopefully I can get enuf shock out of those bullets to put them down, but man i don't know. I'm going to get a 6-284 built by Gre-Tan soon so maybe that'll work better, we'll see.
Don Bower is the guy that used to do all the experimentatiion with the Contenders/Encores. He has a long-range seminar occasionally out in Alliance.