Without a scope, they are about equal for accuracy out to about 75 yards in my opinion. You can only hold so tight with those factory sights. The tightest groups I ever got were with my Winchester 1200 which had a (gee, I forget if it was 24 inch or 26" barrell). it had quite a fine bead and rear notch, allowing for a finer hold. Fifferent slugs will certainly group different. Shoot different slugs on different days, to avoid getting flinchy, to check groups. At 50 yards I can keep the slugs touching each other out of my Ithaca with standard Winchester pumpkin balls.