I got my wife a semi-auto 20ga. shotgun for her to use. She can handle my 12ga auto, but can control the 20 much easier. Her gun is 26" barrell with several chokes (we also hunt dove with it), but we keep an improved cylinder choke in there most of the time. When at home it is loaded with heavy birdshot. She can rip off several rounds in a hurry if need be and still maintain control.My wife has recently asked to get a shotgun for her defense in our house while I am away on business trips. What is the best guage to get her? Also, what kind of ammo would be appropriate?