1. “Knock Down Power” is a myth. It’s a mathematical computation that doesn’t correlate to actual performance on tissue. Greater weight and slower speed DO NOT equal a bigger wound channel. A larger bullet diameter MIGHT, but the hydrostatic effect on tissue (from velocity) and fragmentation is what really makes the permanent wound channel larger.
2. It isn’t perfect, but there are plenty of people who use the same reasoning for the 5.56mm, which you call a “full rifle charge”. It isn’t. It’s an assault rifle cartridge (med power round). I could easily argue that Lake City isn’t making 30.06 any more, but that wouldn’t prove a thing. We moved on from the M-1 Garand as well. Doesn’t mean it was particularly bad, does it?
3. Green tip (M855) is acutally slower than the previous M913 55gr round. You’re correct in the “ice pick” effect, because while the M855 isn’t really “armor piercing”, it didn’t fragment as well as the M193. For that matter, 7.62mm FMJ doen’t fragment like the M193 and, as far as terminal ballistics go, relies 100% on the 37% greater bullet diameter. It’s really only better at much longer ranges and for shooting through cover/armor. Inside common combat ranges (under 100m), the 5.56mm has greater terminal ballistics on the body. Velocity and fragmentation.
Again, there are THOUSANDS of stories about people taking 5, 10 or even “41” rounds to go down. That alone should make any reasonable skeptic say, “WTF?” and rethink the story.
I’ve been told, “I fired the entire magazine and he didn’t go down.”
To which, I immediately reply, “You missed.”
Not to be disagreeable but I disagree. There is such a thing as knock down power - it’s best representative is the .45 ACP round. It was designed to specifically put down drugged up asian muslims who used hemp rope as torso bullet protection. The round did exactly what is was designed to do-put down bad guys fast. The round saw real world testing from Phillipines, WWI, WWII, Korea, and Vietnam. The first time we had close combat with the 9mm in room to room engagements we had problems (7 to 9 hits to enemy personnel before they were down). Two rounds, similar size, big difference in effect due the speed of rounds; 9mm supersonic, .45 subsonic. Likewise with 5.56mm. when we weighted it up for SAW and added more propellant we got ice picks at short range. The original specs on 5.56 represented a very light round with an effective range of 300m max. By design it was supposed to tumble when entering flesh, thus causing a larger wound channel. As we added weight to the round (first to improve rifle range scores at 300-500yds, and second to use as a machinegun round at 700m) and propellant we lost the designed tumbling (instability) properties of the round. Thus it lost its knock down power. See cavitation and bleed out rates. Or just go read the 1930s Pig Board report. This is a recurring conversation with Army/Marines, the argument always ends with the recognition of the size of our ammo war reserve quantities and cost to change round/rifle. Personally, would prefer a 6mm or 6.5mm round for combat, but we are stuck with 5.56mm for a long while.