Terminal effectiveness from 7" AR - 5.56mm vs 9mm
Eberlestock's S25 Cherry Bomb pack is designed to conceal a 7"-ish AR SBR or pistol in a non-tactical-looking pack. I'm thinking about something like this for an AR pistol with the SIG SB15 brace installed, for a car gun. The anticipated scenario is at worst a temporary local breakdown of law and order, not a long-term Mad Max scenario, so it would be highly unlikely to ever need to engage targets farther than 100 yards (probably a lot less).
Going in assumption would be I'd use the same "go to" load I already use in the caliber - MK 318 or Gold Dot 124gr +P, 5.56mm or 9mm respectively.
Which is going to work better from the terminal ballistics perspective from a 7"-ish barrel at ranges under 100 yards?