My SP-101 and most others shoots to POA with 158gr magnum loads pretty well. Unfortunately I usually shoot something a little milder and so it shoots a little low but I have learned to compensate by raising the front sight a little. I think for the type of shooting the gun was designed for (self defense) the sights are close enough.
With my SP-101 3-1/16" .357 I usually shoot 125 gr .38 Spl+P JHP at ten yards at an indoor range. When I do my part it is dead on. With .357's I usually shoot 158 gr JSP at greater distances and things are different, depending on range and conditions.