For most hunters 400-500 yard shots are a dream. Don't even think about it unless you have a 500-600 yard range to practice and can hit a 12 inch circle under all wind conditions.

IMO 400 yards is reaching the outside edge of the 30-06 capabilities. Energy is starting to drop off by that time and while a perfect hit at 400-500 yards would probably still kill an elk, you also need to figure on dropping them pretty close to where they are hit or you may well not be able to find them after working your way over there. Maybe you are capable of that kind of shooting but only about one of twenty average shooters could pull that off.

I once had a bunch of guys out for a steel silhouette shoot and I had to set up two 4x8 sheets of plywood at five hundred meters to even see where they were hitting. On the first round of shots nobody came within 30 feet of hitting the Ram. These were guys who thought they knew where their rifle would hit at that range. This was of course before range finders.