We never heard anything about the cartridges used either by Zimmerman or the retired cop in the theater that shot the text dude. Both were one shot kills with what I consider a small caliber. The bullets did the job.
Depending on where you live, you may not want to give a rabid anti-gun prosecutor an opening. If you’re in a different situation go for it.
Zimmerman used a S&B 9mm hollowpoint, 115 grains. S&B is a Czech manufacturer I believe, and in my home country of Kenya it is one of the main self defense rounds used by those with licenses. I used to use it until I upgraded to Hydrashoks ....and yes, I know there’s newer technology ut Hydrashoks are the best available (and considering we don’t have winters I am not at all worried about plugging). Going back to S&B JHPs ...a hot round (not listed as +P but may as well be), but in the US, where better ammo is the available, Zimmerman must have been poor to have been using it. First thing I would do if I could magically get US ammo is get some HSTs.