I bought a 77/357 afew months ago. I put a relatively inexpensive Bushnell scope on it.
With a 158 gr XTP and a near max load of H110 it shoots groups like this at 25 yds.
I don't have a photo, but at 100 yards it shoots 3-4 inch groups.
I've never shot a deer with a .357 mag because we can't hunt deer with rifles in Ohio. I have to think the load I'm using (when fired from a rifle) must be approaching a .30-30 in terms of power and therefore adequate for deer hunting. Some may suggest a 180 gr bullet for deer hunting however.