The AR-15 is a common and standard police weapon in the US, and as such is a natural choice for a private citizen who is concerned about choosing a proper weapon. A cute little 10/22 that‘s cheap to shoot, or Grandpa’s rusty old Damascus barreled shotgun, or Aunt Millie’s .32 revolver are less serious choices for a serious situation. There is a tendency to enjoy the false economy of going with whatever is at hand, but the seriousness of self-defense, where one’s life is on the line, should allow for spending a commensurately appropriate amount of money. AR’s aren’t cheap, but what’s your life worth? Everything you own and then some!
I remember something about, “And let the one who has no sword sell his cloak and buy one“. The AR is the modern day sword – get one.