I went to the range yesterday with my 870 with smooth bore slug barrel (12 GA). I shoot 7/8 oz slugs 2 3/4 inch and got a good shot group, less then 2 inches on the bull at 100 yds. Just for fun I shot 3 inch Mag 1 oz I figured they would be higher or lower do to more weight and more powder. But what was really intersting is that it was right in line with the bull put all shots were over 4 inches to the left. I cannot blame trigger squeze (right handed) if this was the case it would be to the right. I have a 3x9 scope on it. Any Ideas?