Using common #8 birdshot, we'll fire a round into a ballistic gel block at 20 feet and look at the results. The key point I'm trying to illustrate is whether or not birdshot has the potential to produce sufficient penetration, in volume, that could stop a viable threat in the home setting. It has probably been used for this purpose more times than we wish to count, but with mixed results. We should understand that simply conveying to a threat the presence of a firearm can be a deterrent (a highly preferred outcome), but unfortunately this isn't always the case with an individual or group determined to commit bodily harm, or worse.
NOTE: I am NOT the Author of this video or text.
12 gauge shotgun 00 buckshot at a distance of 20 feet
12 gauge 1 oz Foster rifled slug (hollow base) at a distance of 20 feet.