If you dont want a brake then I agree with the above, use the 270WSM.
I use the 300WSM for those animals at that range and to get similar balistics as the 270, 165 Matrix bullets you will need 200+grain bullets in the 30 cal. Without a break that will recoil hard enough that you won't practice as often as you should to shoot at that range.
Not sure why you don't want a break but I would ask you to reconsider that restriction. WITH a break you can spot your own shots past 500yds as the recoil is reduced enough to get back on target prior to impact. This way you can make the corrections seeing where and how much you missed. Don't think your going to cold bore kill stuff at 800+ I don't care what you read, or how often you practice, it's just not reality even in professional sniper circles. Being able to spot our own bullet trace is invaluable IMO.
In conclusion What bigngreen said about the 270WSM if no break, or 30 cal with 210 bergers WITH break for those animals at that range.......
Just my opinion.
PS, I shoot both calibers.