Comments on Leupold having the longest eye relief in the upper power ranges are correct to my awareness. Just last Friday I did some PD shooting with shots being just beyond 400 yards, shooting with a 284 Win. XP-100 centergrip with a 6.5-20 Leupold scope on it. Shot it about 35 times. One time it did kiss me on the nose--didn't draw blood but let me know she was there. This was using my old favorite load of 59.0 o f H-4831 w/a 140 NBT exiting the barrel @ 2750 FPS.
Most people won't shoot this heavy of recoiling gun with a rifle scope on it, but it can be done if you know your gun & the way it recoils, your limitations, and the constant reminder to get far enought away from it. I don't think I would encourage this for regular hunting though as adrenaline could easily cause you to forget and you could really hurt yourself. Hopefully tommorrow if I feel up to it (been home sick a couple of days) I will do some range shooting @ 600 yards with this set-up and see if my accuracy is any better than shooting my 3-12 LER. I would suggest the 3-12 Burris LER for all around long range shooting and hunting.
xphunter