dear stephenthesuave, i'd like to not turn this into a pissing contest as i don't care much for guns and ballistics and you've obviously done your homework on the matter and have fired the M4 on more than one occasion in your 2.5 years, so I'll leave it at that... that being the case, you could use a less aggresive tone and you probably wouldn't get such a cold response in the future. I've read all of the blogs and forums, and on paper at least you are probably correct, from what I have read. The problem with testing is in the control measures. when you compare a high speed projectile such as the 5.56 at around 3000 feet per second it generates 1000ft/lbs power where as the 9mm at around 1400fps develops in the neighbourhood of 375ft/lbs, now apples to apples, that's a lot more bang for your buck... assuming your 5.56 doesn't fragment or tumble (which they are prone to do... hence the study of replacing it as a man dropper). That being the case, a lot depends on your ammunition selection and whatnot as well, with regards to jacketed/hollo point and the like. i'm was only speaking from my own personal experience on the matter and I have seen 5.56 penetrate cinderblock walls, and body armour, when 9mm wouldn't. again, it depends on a lot of factors, so let's just agree to disagree and get back to the knives.