.410s are hard to find, and quality .410s are near unatainable. Besides, .410 shells cost more and may not always be available.

"Huck" gave you sound advice. A .20 ga. would be much better than any .410, and a .16 or .12 better yet.

It doesn't sound as if the type of weapon is the issue. It appears that your wife is simply against the idea of having a firearm with which to defend herself. Too bad. People unwilling to do what is necessry to defend themselves, whether from man or animal, are usually called victims in the end.

This discussion about "bird shot" is filled with misconceptions.

No. 6s are generally not considered as birdshot, being used most often for small game like rabbits. In the distances encountered inside a dwelling, a load of 6s is lethal enough to get the job done, mainly because the shot has not spread in that short distance. No. 4's work even better. Buckshot only works to penetrate interior walls, presenting dangers to family members that may be in adjacent rooms.