Are you talking about the Thunder Hills Ranch in the southern part of the San Luis Valley? They are supposed to have some real trophy bulls up there.

yeah thats the place

sounds like it should be a great experience. it would be cool to use a bow but i wouldn't give up a chance to go and use a rifle though. either way i would be happy and enjoy it.

They have a website called "thunderhillsbison" (or something similar) that contains a lot of useful information about bison hunting.