Statistically there will always be those outliers that are the stuff of anecdotes and articles. At household distances a hit in the boiler room with any of the three will do the job.......statistically speaking.Ask yourself which load is most likely to do the job if delivered with the same degree of accuracy; the 12, 20, or the .410.
The fact is that law enforcement's overwhelming choice of shotguns is the 12 gauge.
Please oh wise one you think he'd have been better off with a 410 and 1/2 the # of pellets. BTW this also answers JM's question.I remember hearing about an officer involved shooting that happened at around 15 feet inside a parking garage,the officer was using a department issued 12 gauge with 9-pellet '00 buck.
The officer unloaded every round he had in the shotgun,before going to his handgun,the whole time shots were being fired the BG was advancing on the officer,the perp then gave up when the officer drew his handgun.
All pellets hit their mark in the perp's upper body.
After all was said and done the officer admitted that he should have went for a head shot,the perp died on the way to the hospital.
So please oh wise one tell me again how the 12 is so much better than any other gauge.
The only way a 410 is going to be any more effective is if you can actually shoot it faster. Something I figured out years ago in bowling pin shoots speed shooting shotguns is a big mans sport. you just can't cheat physics much.Once again I ask, how is 800 to 900 ft lbs of 5 000 buckshot pellets not going to smoke an intruder.
law enforcement's choice to use the 12 gauge is not a decision that is based on what is the best tool to use but what is simply available to the agency.