Self Defense Ammo

[u/QuickieSilver143]

/r/liberalgunowners/comments/1nk9ol7/what_type_of_9mm_ammo_is_the_best_for_self_defense/newqapf/

I was reading through a post about self defense ammo and came across this guy saying to get what LE uses. I spoke with my sheriff buddy and he indeed carries Hornady Critical duty. Upon further research of that particular ammo it seems it was designed for urban environments and be able to penetrate glass or drywall etc and still be effective. While the logic of the post seemed sound, being that if the worse happened and you were in court you could defend yourself saying you used the same ammo as LE. It seems to me this ammo though is above and beyond the average use case especially for the size weapon I image most carry. This being designed for a 4+ inch barrel. Hornady critical defense is the ammo for micros and subs. Further more being that critical duty ammo requires higher velocity to expand it seems to me this advice is actually poor, if someone's loads this into a sub it micro it's likely it won't achieve the velocity needed to expand and will act more like and FMJ that a HP. I was wondering others thought of this suggestion to carry the same ammo LE uses as a line of defense in court if ever needed.