The Hornady Critical Defense is a good option but the best option is not
If you miss you must ensure that you have picked the best line of fire. Birdshot is never a good SD option. Go with a single projectile and hit your target and pick the best possible line of fire.
From the Truth About Guns site:
Shotgun Penetration With Various Rounds
Posted on February 27, 2010 by Robert Farago
"Wounds inflicted from birdshot tend to be gruesome yet shallow as they lack the penetration required to reach vital cardiovascular or central nervous system structures."
http://www.thetruthaboutguns.com/201...arious-rounds/