I killed my second bird of 2007 with a Mossberg 500 20ga. I was using a Hastings .572 choke, with Hevi-13 #6 shot. I killed the bird at 37 yards. This is a 40 yd combo for me. I have a new Indian Creek .555 choke coming. Whichever choke you pick, shoot serval diff loads to find what works best. Also, there is a lot of info. on the NWTF board.