But several broader questions, unrelated to this thread crop up as a fallout of this particular US policy. I have my own thoughts on this - but they are all completely irelevant to this thread and will not say anything further. Their only connection to this thread may be the connection between number of rounds fired versus kill efficacy. In this connection there can be an endless argument about the optimum ratio of rounds fired to enemy hit, but unless I can find such stats I won't be able to say anything more.
Actually, around the Vietnam war, a number of studies showed that the average US soldier was becoming a worse shooter than before. In WW I, the average American soldier expended about 7,000 rounds per enemy casualty. In WW-II, this number went to approx. 25,000 rounds per enemy. Korea doubled that number to around 50,000 rounds per enemy and estimates for Vietnam were anything between 200,000 and 400,000 rounds per enemy body count (250,000 is cited by at least two authorities I read)
One of the main reasons for this was because of the rapid industrialization of American society. Basically, people were buying their food at the grocery store instead of hunting for it. As far back as WW-II, people in the USMC had noticed that country-boys seemed to be better shots than city dweller folks and also knew how to take proper care of their weapons.
The training methods that were in use before the Vietnam era were also not optimum and the reason it didn't show up as much earlier was because a lot of the GIs already knew the basics of marksmanship in earlier wars. During the days of war of Independence, Civil war, wild west etc., entire units of excellent marksmen could be picked from a small population of backwoodsmen and frontier people.
In the 1940s and 50s, Colonel (later Brig. General) SLA Marshall did some influential studies about how soldiers did in combat and claimed that only 15% of soldiers would fire their weapons at the enemy because of the fear of killing another human being, rather than the fear of being killed themselves. Based on his papers (especially "Men Against Fire"
), the solution that occurred to the military was to train people to shoot under combat conditions, overcoming their instincts. Instead of teaching a soldier to shoot a target; the Army decided to instead condition him to kill, and the best way to do it, unusually enough, was to de-emphasize that shooting = killing. The thinking at that time was that a soldier who has learned to shoot carefully at a target in peacetime, will also take the time in combat situations, to think about the family of the man he's about to shoot. Hence, the solution was to train soldiers how to quickly shoot massive volumes of fire without giving them time to think about it, and also into places where enemy soldiers might be hiding (e.g. trees, houses, soft vehicles etc.), because Marshall's studies showed that the soldier will have less reluctance to firing on a house or tree than upon a fellow human being.
Therefore, the military placed less emphasis on shooting at a fixed target (known distance shooting) and more on shooting at high volume of fire at pop-up targets (the Trainfire system). Here's one study from 1958
The advantages of the Trainfire system was that it supposedly simulated combat conditions and produced soldiers more quickly (17 hits out of 40 was considered pass), but people trained by this system shot less accurately than people trained by the Known Distance program. The problem also was that the Army went straight to Trainfire without teaching recruits the fundamentals of basic marksmanship that Known Distance shooting taught. This meant that a lot of guys knew how to pull the trigger, but not why they were not hitting their target. By the early 1960s, the Army had practically phased out the Known Distance program and were emphasizing a Trainfire based program called Quickfire, which was very spray-and-pray.
By the Vietnam era, a guy named Major Wigger of the US Army did a bit of research on your average GI's shooting skills. The man was a world class shooter on the US team and a shooting coach to boot. What he discovered was that the average GI couldn't hit a man-sized silhouette at 25 meters and didn't understand why he had to zero his sights.
Around the same time, Master Sergeant Heugatter of the 25th Infantry Division found a similar situation among the soldiers he was training. Only about 10% of the soldiers he tested could actually hit a 1x1 foot target from 25 meters. Most of the guys didn't know they should zero their sights, and in several cases, the front sights of the barrels were unadjustable, due to rusting from poor maintenance! What really shocked the Sergeant was that this lack of knowledge was not just restricted to enlisted draftees, but also to officers and NCOs.
The most dramatic demo about how basic marksmanship training could help the average GI was given by a Major Foster of the 101st Airborne Division. He would bring up groups of 30 seasoned combat troops and tell them to select the worst shooter in their group. Then he would line the remaining guys with their M-16s and two 30 round clips each and tell them to shoot at a man sized target at 50 meters, with as many rounds as possible in a one minute limit (with no requirements on rate of fire or firing position). Invariably, the soldiers would shoot in the standing position in full auto mode and would hit the target maybe 4-5 times with 1800 rounds of ammo! Meanwhile, while the rest of the guys were shooting at the target, he would give the worst shooter some basic marksmanship training instructions for 5-10 minutes. Then the worst shooter would step up and only fire from the prone position and only in semi-automatic mode and would invariably hit the target more times with his 60 rounds than the entire group with 1800 rounds.
Because of all these common findings coming from different branches of the military, they began to once again emphasize Known Distance shooting and teaching the basics of marksmanship to the GIs, before going to Trainfire system.
See this article for some more details:
Incidentally, a lot of people have debunked some of the claims in Gen. Marshall's papers:
Sorry about the length of the post