They can be effective. They are suboptimal at best. The .22 should only be used if you have no ability to shoot a more serious round (which likely includes my wife) or nothing else available. As for birdshot, hell no. Although the shot will be very close together and one must in fact aim, the penetration is inadequate. An offender wearing any kind of coat is far too likely to have ineffective wounds.

Over-penetration is generally not at all the problem that has been portrayed, at least if one is using duty ammo that meets the standard and has been tested and proven to do so. If you are really concerned about the risk in a residential setting, the best answer out there (other than "don't miss") is 5.56X45 duty ammo.

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NHI, 10-8.