RE: Open sight Ruger 77/50
No matter what style of rifle you like, they are muzzleloaders. You sound like you have an excellent bullet combination for the 100 yard shooting you expect. Also with the kind of accuracy you are getting, I too would be giving the Ruger a chance in the field. I always liked Ruger firearms. They just seemed to fit me real well.
Keep up the good shooting and good luck with the rifle in future hunts.