IMHO, there are two issues that need to be split when talking about this:
1) The bullet technology that the FBI report references from links above is the same across the board - ie expanding bonded bullets. It has solved the jacket separation issues common in traditional jacketed hollowpoints. Ammo manufacturers create and promote SD ammo to sell to LEO's and governmental organizations that buy ammo by the pallet. These manufacturers are not mainly producing your favorite flavor of bonded ammo just to be bought in a box of 20 at the "big box outdoor store." The plain fact is that there is no special technology being incorporated into .355" that isn't in .400" or .451". We can use these products as examples: Speer Gold Dot, Win Ranger T, Rem Golden Saber bonded, Fed HST bonded, which are manufactured in 9/40/45.
2) Issue #2 is not the "What's available?" but the "Why did the FBI go back to 9mm?" It was not
solely due to bullet technology and anyone who makes that argument is misinformed. The answer lies right there in the report. They didn't choose 9mm specifically on bullet technology, but also that "participants shot more quickly and more accurately with 9mm caliber." It was not a "caliber performance" issue, but it was a "participant performance issue." Most people would say that both 40S&W and 45acp are more difficult to demonstrate proficiency in comparison to 9mm.
Additionally, the report cites that, "shot placement is paramount and law enforcement officers on average strike an adversary with only 20 - 30 percent of the shots fired during a shooting incident." This should clue the reader into the direction that the FBI is arguing for in their evaluation.
If the previous quote wasn't enough, then," 9mm Luger offers higher magazine capacities, less recoil, lower cost..."
The report reveals the reasoning. It's
NOT at "9mm has special bullet technology" line of reasoning.
They concluded that:
- More participants could shoot 9mm more proficiently
- If only 20-30% of shots fired landed, then a greater magazine capacity was important
- And "shot placement was the most critical component to achieving either method of incapacitation."
It is an understandable line of reasoning, even from the perspective of those who do not agree with it.