[pdoktar]

The "9mm BB", is roughly comparable to the .45ACP in stopping power and has better ballistic characters and is easier to carry and fire. Nowadays the culture in american gun magazines and "I used the .45ACP with deadly effect, as my other 9mm Para just glanzed off the enemy"-stories and the fact that SOF uses .45ACP is turning again the favor in the army towards the .45ACP and it´s "massive" stopping power. As the current .223cal assault rifles have the real problems in stopping power, and nothing can be done about it, they´re reflecting this to such personal levels as wanting a pistol that has the stopping power needed, whether the older caliber would be adequate, or even better for as a last-ditch weapon.

Pistols are useless in combat. If any truck driver is fighting off the enemy with his service pistol, he´ll get killed after dispensing his first magazine, whether or not using 9mm or .45ACP. Switching calibers back from 9mm to .45ACP would be pure idiocy.