Shoot from a bench rest just like you would a rifle. Some chokes don't shoot to POA. 55/45 is ok some guns are made to shoot a little high your eye is the rear sight so a small change in sight picture can change that a lot. 60/40 at 25 yards would be off quite a bit at 40 yards.You should have had a 100% pattern at that range using the standard 30" circle. Hope this helps.
