57K, Miami was not the only example, it is simply a well-known one.
There have been numerous reports from Force on Force training classes of disproportionate percentages of hits to the adversary's shooting arm, due to fixation on thhe threat (the gun) by shooters.
I have heard the same reports from people who study gunfight results, and from people who teach military and LE. This makes perfect sense to me, since I see people react the same way in martial arts classes, when weapons are introduced. Typical training scenario starts with technoque vs a static grab, then same technique vs a dynamic grab, then same technique vs a straight punch, then a hook punch. People get a bit more tense when fists start coming in.
They really get tense, and fixated, when clubs and training knives replace thhe fists. Their feet don't move right, and their hands naturally seem to go toward the other guy's weapon.
Meanwhile, your example of the Silvertip inflicting a non-survivable wound involved, IIRC, tearing the brachial artery. This amounted to luck, as much as placement.
Your references to an engineering background and your rodeo experience probably meant something to you, but they did not translate well. Could you clarify what you were trying to say?
Your reference to shot placement always being most important undermines your argument that the 147 is ineffective. If the 115 and 124 are so much better, why does placement trump? (I agree that placement trumps; I don't think most people are that good at hitting moving targets with precision, particularly when those moving targets shoot back. Hit percentages and rounds per stop in LE and military shootouts would bear out that idea.)