In answer to the OP question, the 9mm 116 gr Silvertip bullet that killed Platt and rendered him a "dead man walking", quite literally performed at a level exceeding the FBI's subsequent and current performance minimum.
If you get a copy of Dr. French Anderson's book on the topic, "Forensic Analysis of the 1986 FBI Miami Firefight" (available thru Paladin Press and/or Calibre Press, last I looked) you can review Xrays that show the bullet core came to rest in the right hilum (the "root" of the lungs, where the pulmonary arteries and veins come together with the bronchi and connective tissue). This is a highly vulnerable area in the chest, in many respects more vulnerable than the heart itself.
Details from the autopsy report indicate that the bullet lacerated the pulmonary artery and/or vein. This resulted in massive internal bleeding into the right side of the chest which would have resulted in the subject's death within 3 or 4 minutes even if he'd not been shot again. It's impossible to speculate as to whether a .40 S&W or .45 ACP or any other service caliber handgun round could have done a better job, but in my opinion it's doubtful.
The other posters who've logged in so far have all made valid points, so I won't amplify except to say I agree. If know you're going to be in a gunfight, bring a rifle. And bring friends with rifles.
The 1986 FBI Miami firefight was the LE equivalent of a perfect storm. So many things went so badly wrong in such a short period of time that you couldn't make the story up and have people believe it. But it really happened, and the numerous lessons learned have had enormous impact on law enforcement equipment, tactics and training, and protocols not only in America, but throughout the world.
The agents who were killed and/or disabled in that fight were all heroes, in my estimation, doing the best they could have done with the equipment, tactics, and training they had; and the lessons they paid for with their blood have saved the lives of countless officers since.
