ORIGINAL: Sniper151
Would you rather wound the enemy and have him continue to fire at you or drop his butt in his tracks? In the jungle of Nam the emeny would just get behind a small tree. The M-16 would not penetrate and he was safe. Now he cuts loose with his AK that will go through trees and limbs and you are up sh--ts creek. The FMJ bullets were adopted during WW I to penetrate through as many of the enemy as possible to cause wounds. Todays battles in Iraq are a different deal. You don't have hundreds of enemy charging over open terrian in a line. An expanding bullet would stop the towel heads in their tracks. I want caliber and bullet that drops the enemy in his tracks with one shot. One little hole in the front with a real big one in the back.
You can go look up penetration data, but the 7.62 x39 AK round is not that highly powered, the case is very short, if you have ever looked at one. I highly doubt it penetrates so much greater than a 5.56. It is NOT the equivalent to a .308 or 30-06 load (as many people mistakenly think). We don't use expanding bullets due to the Geneva Convention. Now, which one do you want, more penetration or expanding bullets, you can't have both...
Check out some ballistic geletin tests and also the box o' truth:
http://www.theboxotruth.com/