sure. Dept of Justice annual Crime Survey
shows that 65-75% of all attacks are not made with a gun, so at what range can you justify shooting them, eh? 10 ft or less, and that's measured from your chest to his. The muzzle of a shotgun is 3 ft closer to him.
'Every year, the FBI'S Uniform Crime Report says that over half of the GUN fights occur at 10 ft or less, and that's with COPS. Cops tend to have longer range engagements than civilians can justify, and that skews the average range to be longer for cops than it is for civilians. So, 70+% of the time, it's at 10ft or less, because the attacker has no gun, and over half of the remainder of the time, it's at 10 ft because that's how crime goes down, for civilians. So, nearly 90% of the time, it's at 10 ft or less. Few homes have rooms that are more than 20 ft square, and few attacks are from one corner to another. So the odds are at least 6 to 1 that you will (if justifiable in Court) fire at less than 10 ft, and the odds are about 20 to 1 that you will fire at less than 20ft.