Still watching, but I had to stop to post this comment. Very interesting information regarding the smaller caliber rifle bullets, which is the 5.56mm in this presentation. I just brought this exact reference up in another thread about a short barrelled rifle, SBR. Someone wanting a 10.5 and I suggested the 11.5, due to the extra velocity between the two - pretty big difference for an inch. Fragmentation is the key, and muzzle velocity is the key to that. Here's what the Doc has to say about it in his presentation: "very interesting for the small calibers, and how they function - or, are supposed to function... if you look at the new, modern high velocity rifle ammunition, the 5.56mm, the injury mechanism is actually not the direct destruction by the bullet, but the fragmentation and jarring of the bullet. ...the bullet fragmentates, and causes these large cavities. this is the idea, or the concept behind it. ...and this how these bullets became so deadly, that only when the fragmentate..." I'll state it again. Fragmentation is the key. Back to the video now... <munch>