I will probably deeply regret this but:
"If I remember right it was a .38 special to the neck which ended the scumbag Platt."
Platt's official cause of death was caused by the bullet fired by Agent Dove. This is a very famous wound track as the bullet stopped just short of Platt's heart after driving through his arm (severing the brachial artery) and entering the lung. Platt was later shot in the clavical area and the round came to rest against his spine and probably bruised it. This wound likely paralyzed him which gave the chest wound time to work.
The round that really bothers me was the one fired by Agent Risner from over 30 yards away. This round came in from the side and first contacted the tricep before striking the back and stopping against the ribs without penetrating into the chest wall. Nobody focuses on this round and it is the one that I find most disturbing. It is likely the result of a lightweight (115 gr) hollowpoint fired from a distance sufficient enough to bleed off too much velocity. The bullet lacked the momentum to penetrate the chest wall. Again, this wound was received before Platt killed anyone.
Yeah. Momentum tends to predict penetration - it simply the likelihood that an object in motion will stay on its path when it encounters resistance. In other words, if you line the shot up well, the round with the most momentum will have a greater tendency to stay on that path.Momentum? Really?
Another measure that tends to correspond well with penetration is cross-sectional density. This is why the 147 grain is so popular when deeper penetration is desired.
I'm not saying that more momentum makes up for poor shot placement. I am saying that more momentum rewards good shot placement.
I'll also offer that if an agency transitions from 40 to 9mm and takes the 20% ammo savings and shoots 20% more, then I am all for that. How many will?