Thank you for your input, realistically I would like to keep most of the shots 1000 yards and under but given the opportunity and right conditions I would love to be able to reach out and touch coyotes, hogs and maybe a deer even further. I already have 100 peices of norma brass, and all stuff to reload the 7 rem mag so that's why I'm kinda temped to just keep it as a 7RM and in the future build something a little bigger like a 338 to take care of the big stuff farther out. To reach those speeds with the 168s, and 180s I would need a barrel 28-30in? What twist rate would best be suited for them? Thank you.
I don't know how much experience you have shooting at "long range". My opinion is that 1000yds IS reaching out and touching them! Also, I am in the same boat as you with a 24" 7mm rem mag that is waiting to be a dedicated long range rifle. It's going to remain a 7mm rem mag, but it will be getting a 28" barrel along with a brake so I can spot my shots more easily. I would not be too worried about going with a 1 in 9 twist barrel vs a 1 in 8 twist. I don't think the 7 rem mag can push anything over 180 grain fast enough to beat the 160-180 grain pills(Diminishing returns). The larger cases can really smoke with the new Berger 195.