What is the highest caliber rifle and highest scope you can use in Oregon for hunting?

.308's are good. They should be able to take down any animal in the North America. As far as highest caliber? Not sure but the .577 t-rex is one killer gun. Only practical use for it is to take down elephants. Just search on yahoo video/youtube .577 t-rex recoil. In UT it is not against the law to hunt with that. But then again why would you? As far as I know you can hunt with that gun. And there are no regulations on scope.