I use 147 grain Speer Gold Dot G2 for this reason. The sentence below was pointed out to me from an article titled why bullet size matters, from an attorney that is used exclusively by our State Patrol when defending against officer involved shootings.
"The 2014 FBI Training Division Report stated that the FBI had chosen the 9mm bullet (147 grain Speer Gold Dot G2) for FBI agents to carry because, “The 9mm provides struggling shooters the best chance of success while improving the speed and accuracy of the most skilled shooters.”
Although it specifically states the FBI he told me that it is standard issue in many police units as well. The reason he recommends that particular bullet is if you are ever taken to trial for a defensive shooting case, one of the questions that will most probably put out to the jury would be a question of what bullet you used and why after making the 147 grain Speer Gold Dot G2 sound like the evil stepson of the atomic bomb. The simple answer is "it is standard police issue so I figured if they recommended it to keep police officer safe, I followed that recommendation to keep myself safe"