That 7.5 shot. Maybe they ascribe to the idea that they don’t want to shoot through the walls. (Hint - if it won’t go through sheet rock, it won’t go into a bad guy either.)
There was a shooting last year at my son’s college. Thank God the nutcase was an idiot. He killed one student with a shot point blank to the head. Several other kids were shot at a bit of distance, walking to the ambulances with large red rashes. No doubt birdshot.
One student overpowered the shooter while he reloaded.
There is only one size of 7.5 or 7 1/2 (however you want to write it) shot that I can see and it's typically used for dove or quail. 350 pellets per oz. That's a lot of pellet plucking for the unlucky surgeon.
Within ten feet it would probably act a lot like a slug entering your poor unfortunate body like a single mass. Although it would slow down faster and disperse. Further than that and it would be pretty iffy unless a pellet or more hit some vital arteries.