Your lawyer friend is in the minority.
If a DA does try that approach you have a simple irrefutable response:”No sir, I know I’m not a police officer but I use the same ammor for the same reasons they do. Are you saying their reasons for choosing their ammo are not valid?
It is the same reasoning as not using handloads “Standard ammo wasn’t enough, you had to use EXTRA KILLER AMMO!”
He suggested a nice hunting load in certain areas. It does depend where you are.