Dan was doing grouse hunting seminars a few years ago and part of the program involved shooting several brands of commercial shotgun shells through each clients gun and checking the pattern. We noticed an amazing difference in the patterns produced. Some patterns were full of voids because the pellets were grouped in tight bunches of 6 to 8 pellets in 1 in. groups. Other loads produced nice evenly dispersed patterns from the same barrel. Hunting loads contain soft shot and tend to throw a big pattern and high grade trap and skeet loads contain harder shot and tend to throw tight patterns. Buy a box of several different brands and shoot some paper. You may find a certain brand suits your gun better than another.