That is a good pattern with a 12 gauge as well. I'm putting anywhere from about 27-34 BB's in the head and neck at thirty yards with my 20 gauge so I'm pretty happy with it. I have heard very good things about Indian Creek Chokes, as well as they are expensive. But if it kills you a bird, its all worth it.
I finally bought an Indian Creek after hearing so many good things about them, and I'm glad I did. After paying shipping I paid $82 total for it, but in my eyes it was worth it. After work today I'm going to run some hevi shot through it and see what happens. If my camera will work right I'll have some pics up by tonight.