AP writer Slobodan Lekic’s semi-cogent article the suitability of the M-4 in Afghanistan misses the point. Actually, it lacks one. Was he trying to introduce the Army’s new policy of having nine M-110 SASS equipped “sharpshooters” in each company? Suggesting that the U.S. military is fighting the Afghanistan war with the wrong weapons (a point he contradicts when he acknowledges that most firefights in the conflict are at distances within the M-4′s ideal operating range)? Anyway, there’s some good intel with re: the suitability of various calibers at various ranges.
The U.S. military’s workhorse rifle — used in battle for the last 40 years — is proving less effective in Afghanistan against the Taliban’s more primitive but longer range weapons . . . a U.S. Army study found that the 5.56 mm bullets fired from M-4s don’t retain enough velocity at distances greater than 1,000 feet (300 meters) to kill an adversary. In hilly regions of Afghanistan, NATO and insurgent forces are often 2,000 to 2,500 feet (600-800 meters) apart.
Kalashnikovs aren’t any better:
Soviet soldiers in the 1980s found that their AK-47 rifles could not match the World War II-era bolt-action Lee-Enfield and Mauser riflesused by mujahedeen rebels.
Lt. Scott Doyle, a platoon commander in Zhari, said his troops are usually facing Taliban AK-47s. ”When the Taliban get past 300 meters (1,000 feet) with an AK-47, they are just spraying and praying,” he said.
Don’t blame it on the cartridge:
Martin Fackler, a ballistics expert, also defended the 5.56 mm round, blaming the M-4s inadequate performance on its short barrel, which makes it easier for soldiers to scramble out of modern armored vehicles.
“Unfortunately weapon engineers shortened the M-16′s barrel to irrational lengths,” Fackler said. “It was meant for a 20-inch barrel. What they’ve done by cutting the barrel to 14.5 inches is that they’ve lost a lot of velocity.”
As the Taliban have proved—by using their “inferior” AKs to “herd” U.S. troops towards IEDs—strategy is often far more important than firepower. Armchair analysts would do well to acknowledge that brain power trumps firepower every time. Well, almost every time.
Yep, that's right. The 5.56 round in a 20" barreled rifle is capable of muzzle velocities in excess of 3200 fps; with a 14" barrel it goes down to around 2200 fps. The shorter barrel kills velocity and therefore downrange energy.
In terms of killing power, I think the M16 started to be neutered with the advent of the A2 version back in the early '80s, which changed the barrel twist from the original 1:14 to a much tighter 1:7. This was done to stabilize the so-called NATO SS109 69gr boat tail bullet. The original AR15/M16A1 used the lighter 55gr "ball" round, and with less barrel twist it was known to tumble upon entering the body and hitting bone, causing "secondary missile" damage to tissue. The more stable 69gr bullet doesn't.
Combine this with the short M4 barrel and you have an ineffective weapon at ranges much beyond 200 meters.
As I understand it, the standard nato round will still tumble and yaw, even when fired from a 14.5 inch barrel. Both the m193 and m855 nato round will tumble, yaw, and most importantly, fragment if fired from a 20 inch barrel. The greatest wounding effect from the 5.56×45 bullet (whether m193 or m855), is due to fragmentation. The shorter 14.5 inch barrel doesn’t produce enough velocity to reliably fragment either the m193 or m855 bullets.
The larger 7.62×51 nato cartridge bullet creates its wounding effect more from a larger wound channel, and some say, ‘hydrostatic shock’. Hydrostatic shock, by the way, is still questioned, and debated over. ‘Big bullets make big holes’, is still true. The 5.56×45 m193 created massive wounds out of proportion to its small size, because of massive fragmenting and deflection.