I read all sorts of studies about wounding values for various mil-spec ammo, including the Hatcher and Evan Marshall Studies as well as the FBI stuff that led to the adoption of the 10MM and later the now being discarded 40 SW. I also spent a lot of time with the guy who won the National Service Rifle championship (Jack Caseman) of the USMC shooting team and why the USMC and the USAMU (Ft Benning) gave up the M14 rifles in favor of the M16 rifles for national matches-even with some of the stages being at 600 yards.
what I learned from all of this is the following
1) while a 762 NATO Round is more lethal, 556 was far more preferred in a military context where the main goal is infliction of casualties on the opposition. The standard load for an infantry operator in 762 was 8 20 round magazines. For the M16 it was 9 30 round magazines. 270 rounds of 556 is far superior to 160 rounds of 762 for that purposes
2) for SF or patrol types, the M16 allowed far more ammo to be carried. My nephew, who has had close to five years of heavy combat experience-first in the Rangers and later as an A camp commander in Afghanistan, noted that even in the sandbox, most of the engagements were under 250 yards and stuff longer than that was usually addressed by firebase artillery or gunships. The Marine champion noted that the fatigue from shooting dozens of rounds of 762 is noticeable, he could fire six times more 556 than 762 and be fresher., and this guy was not a normal soldier or marine, This guy was the best military rifle shot in the USA and maybe the world.Current top rifle shot-Ben Cleland has said the same thing.
3) The wounds that the M16 cause, are better from a military standpoint as well -especially with the Vietnam era rifling, since it didn't blast straight through an opponent (thus not dumping most of its energy) as the 762 did, rather it yawed and caused far more tissue damage which required more attention by medical personnel.
The Marine Corps qualifies at three different ranges: 200, 300, and 500 meters (yep, they use meters, not yards). At each range there are different firing positions. At 200 meters you fire from a non-braced standing position and the kneeling position. At 300 meters you fire from the kneeling and the sitting positions. At 500 meters you fire from the prone position.
The highest possible score is 250, and you must obtain a minimum of 190 in order to qualify. A score of between 190 and 209 will get them a Marksman badge. A score between 210 and 219 will earn them a Sharpshooter badge, and a score of 220 or above qualifies them for an Expert badge.
The damage the M16 causes has very little to do with the weapon, and everything to do with the ammunition being used. The M193 anti-personnel ball round was specifically designed to be off-balance. Not only does the round spin as a result of the rifling, but it also tumbles end-over-end as it travels towards its target. That tumbling action causes the round to behave very strangely when it impacts a human body. The round has a tendency to ricochet around inside the body, so you never know where (or even if) there will be an exit wound. You could be shot in the butt and have the round come out your foot, breaking every bone in your leg as it travels.
The round was designed to inflict greater injury, but not necessarily death since it is such a small caliber. The idea was that more resources would be used by an enemy treating their wounded than caring for their dead. Therefore, having more injured than dead was the preferred goal.
It naturally depends upon the terrain, of course, but I very rarely have to shoot anything further than 100 meters away. I hunt primarily in forests and that explains why my range is so short. If I had to drive all the way up to the north slope to take a caribou, where there are no trees for hundreds of miles, then I would be required to take them from a much greater range. Fortunately, I don't have to drive that far to get my annual caribou. I just call the Park Rangers and find out how far away the herd is from the highway. When they are close enough I drive up, hike a half mile from the highway, and bag me a caribou. I don't consider it hunting, since there is no skill involved. More like rural grocery store shopping, except that I'm also the butcher.
