Not sure if you cleaned it good first, but that would be a good idea. You will also want to shoot at a bigger piece of paper (30"X30"), so you can see the whole pattern to be sure of your POI. Also, shoot at 40 yards and then draw a 10" circle around the densest part of your pattern. Almost every shell out there looks good at 30, its crazy how much of a difference that 10 yards can make. It is also a better way to compare apples to apples, as this is what most here do.
Also, read the thread on barrel polishing. It can make a big difference.