Maximum Effective Range of the 5.56
Good discussion folks!
Back in the early 70's, the Maximum Effective Range (MER) of the M-16 was listed (by the Army) as being 480 yards. Marines, being a bit put off by this Mickey Mattel gun, were shooting at 500 yards for qualification with iron sites. Since that time, Marine (if not the Army) have gone to bull barrels, heavier weighted bullets, improved powders, the new Open Tipped Match (OTM) cartridges (to penetrate windshields - needed the Geneva Convention to approve that one!) and tightened up on the quality of the service rifles, issued combat scopes, trained designated marksman whom they issued upgraded M-14s.
On one base, I noticed that two rifle (500 yard) ranges were almost facing each other. The Northern one (I'll call Range A) was facing Southwest while the Southern (I'll call Range B) one was facing Northeast, but actual flight path of bullets from each range would only intersect the flight path of the other range's round at about 30 degrees off set and not head-on. I figure closest these two ranges were to each other was around 1700 1900 yards. Firing points from one to the other range (at least from the 300 yard lines of both respective ranges) was closer to 2,000 yards (about 1 nautical mile).
What came up was an investigation due to the fact that one shooter, in the prone position (on Range B), was struck by a bullet that no one heard fired on that range. Subject individual was struck in the back just below their neck. The bullet pierced the skin and lay just under the skin but did not penetrate the muscle layer below. So, this range (B) with the wounded shooter believed that the other range (A) had fired it, since no one on that range had fired a rifle at that point.
Now I won't go into the hoopla and official jargon that was bantered about in the official report which I considered a whitewash. My personal feelings from what I know and seen, I believe Range A was commencing fire when this happened, so shots heard would have been expected. However, anyone familiar with the M-16/AR-15 or M-1 or M-14 will understand that sometimes the bolts slam home on their own! At least not intentional. While slam fires are rare, they are not impossible and my guess is that it was either a slam fire or the trigger finger of the shooter going through a stress reaction. The maximum range of a 5.56 (55 grain bullet) is about 2000 yards or about the same as a .22 bullet both being fired from a rifle.
So, The M16 Rifle, using a 55 grain bullet, backed by a qualified shooter using iron sights, is known to be able to hit a target, most of the time, at 500 yards and be lethal.
At 2000 yards, the 5.56 can and will pierce skin on a human being. M855 will actually penetrate a heavy layer of clothing but not serious armor.
Keep in mind, the military also used to qualify people with the M-14 7.62 NATO on 500 yard (known distance or KD) ranges.
So, a carbine has a MER of about 400 yards, using iron sights with an average qualified shooter. Shorter barrel, shorter sight radius, less acceleration of bullet and is still lethal.
So, the question is: what is the maximum range a lethal shot has been taken?
My next question would be: what were the qualifications of the shooter, what was and what modifications had been made to his or hers platform, what was their ammunition and what sighting device did they use to achieve this lethal accuracy and what was the weather like at the time the shot was taken?
If Sgt Eagle-eye makes a 700 yard kill using an M-4 carbine, that is great! I am sure he is an expert rifleman because I do not think I could do that!
However, if he is a military Marksman (lowest rating for qualification) and was using a standard GI issue M-4 with a ABC IseeEm scope, that would be helpful because now I know what I can do when I go out for hunting Wiley Coyote.
