Rear sight is Lyman 66 peep with a brass bead on the front. I never tryed to shoot groups, but it shot well when I sighted it in. My load was 525 gr LFNGC bullet with 48 gr IMR 4198 at 1750 fps. It can be loaded higher, but I prefer keeping hard cast below 1750, because anything more and you will lose penetration due to bullet deformation.
A few years ago at a campout with some friends from Levergunlovers.com in Wyoming we we shooting into a log that was about 30 inches in diameter and my gun penetrated the entire log. I would guess it would not have any problem going though a Brown Bear from end to end and that is what that caliber was designed to do. Load it up with some solids and I would not hesitate to hunt anything on the planet.