OK so lets look at that last little thing, which seems quite typical of the entire thread.
#8 shot will go trough walls and cause life threatening injury, but is in no way usable due to its ineffective penetration?
Does that mean that it is not useful in open field of fire but IS deadly if it goes through a wall first?
And why do I need 8" of penetration to hit organs that are only 3 inches from the body surface?
And how are you killing game if the shot is bouncing off the skin?
This entire thread has turned into a tangle of impossible contradictions.
I get the confusion, so I'll explain a bit.
The standard for penetration on human targets is 12" or more in calibrated gel. This isn't the same jello you see a lot on youtube, but gel that has been formulated and maintained at a controlled temperature and a calibration BB is shot through a chronograph to validate the penetration depth of a steel BB at a controlled velocity range. That gel more or less correlates to average tissue penetration (an example is there is a demo video of a pork hind half with gel behind it, and a block of plain gel, and the demo shows equal penetration depth). Not all tissue is equal so 4" of gel penetration does not mean you will get 4" into a chest even on an unobstructed frontal shot. 12" comes from a worst case path to the heart from the rear right, but it also relates to various obstructions that routinely happen in defensive shooting, and the FBI group that came up with it continues to back it as being the benchmark of a round that will consistently penetrate to the vital organs.
Penetration to vital organs is critical in forcing an assailant to stop rather than hoping the mental impact and pain compliance are sufficient. Penetration to vital organs is NOT critical to inflicting horrible gruesome wounds that could eventually result in death or permanent disfigurement. Birdshot does not bounce off skin at defensive ranges. It tends to tear it to hell and stop at the first bone or cartilage layer. It also tend to rip out teeth, destroy eyes, perforate major joints, rupture intestines, so on and so forth, but none of those are consistent results or reliable for ceasing a dedicated assailant. Look up the first two face transplant recipients. Both took bird shot point blank to the face and were able to call 911 afterward.
If you shoot an assailant, they have a fair chance of dying, or they might be disfigured for life, but right then and there the only thing that matters is that it is their choice if they will continue fighting or not. So long as they continue to be a threat, you should be doing everything you can to take that choice away from them in as short of time as possible. If you shoot your kid in the next room over, he has a fair chance of dying, or he might be permanently disfigured, and the only thing that will matter at that moment is the fact that your kid just got shot and his life will never be the same.
Bird shot doesn't make shooting indoors any safer for bystanders. It just means your assailant gets to choose when to quit rather than you choosing for him.
