Hi, I have read various threads regarding defensive caliber choice for handguns. My question is, How does the 16.5" barrels of the Beretta CX4 Storm, Kel-Tec Sub2000 and Hi-Point carbines change the equation when selecting caliber? (9mm, .40 S&W and .45 ACP rounds) (The Kel-tec only comes in .40 and 9mm, but the other two manufacturers make carbines in all three calibers.) For instance, the Kel-tec claims that the Sub2000 in 9mm has the energy of a .357 magnum at the muzzle, a 9mm @ 100 yards, and .380 at 200 yards. There is no data available for .40 and .45. Does the extra barrel length increase stopping power, and allow for the selection of a smaller cartridge while still retaining the stopping power of the larger cartridge? Thanks!