Another +1 for semiauto 20ga. Semiauto for the reasons previously stated - one hand use, etc., as well as not having to worry about remembering to pump when excited and stressed (happens - heck, I've gotten distracted at the range and couldn't figure out why it wouldn't shoot afterward). 20ga because it's completely adequate at HD ranges with 2-3/4" #3 buck loads which will don't beat up the shooter and allow faster recovery. Also generally lighter and more easily handled, especially useful if any smaller statured individuals are going to be handling it. I'm actually in the process right now of changing from a 12ga pump to a 20ga semiauto as the primary HD gun for essentially those reasons.