If you're shooting "V" notch or square notch open sights, then I'd say you're doing really good with 1.5-2" groups at 50 yards. I've never been a great fan of such sights because they lack precision, but if you keep your shots 100 yards or less, and shoot like you say you are now, you're going to put deer in your freezer. If you want to stay with non-telescopic sights, you might look into installing a Williams aperature (peep) receiver sight. You can get them with different aperature sizes, so you can use a smaller (1-2mm) peep for daylight and target shooting and a larger (2-4mm) peep for hunting and low-light. A peep sight will definately improve your shooting because your eye automatically centers the front sight in the round peep hole, making sight alignment much more precise and natural compared to blade sights.

Mike