The range and stopping power problems of the M-4 rifle in Afghanistan has ignited a collection of smoldering controversies among those who provide and use infantry weapons. The problem with the M-4 was that, when using the heavier, "man stopper" bullet, the effective range of the weapon was only about 500 meters. Using the longer range, lighter, armor piercing round, you got an effective range of 800 meters, but much less man stopping capability (especially against a jacked up religious fanatic.) The 5.56 mm bullet will tumble inside a man if it hits at a speed of at least 2400 feet per second. The shorter barrel of the M-4 reduced velocity so that the bullet dropped below 2400 feet per second after it had gone 50 meters. At that point, it was just a fast moving .22 caliber bullet. It can hurt when it hits, but it won't knock the average guy down and out of action. Special Forces troops in Afghanistan have gotten around this somewhat by using a custom made round that ups the velocity enough to knock a man down at 200 meters range. This does still not solve the problem of firing a bad guys a kilometer away, from cross a mountain valley. To do this you need a full power, 7.62mm round, like most snipers use. Many armies still have one guy in each squad armed with a sniper rifle firing a larger round. But even that would not have eliminated the problem of fighting in Afghanistan, where the ranges tend to be longer. A close examination of the CIA and Department of Defense studies made of the 1980s Afghanistan war should have made it clear that even the Afghans recognized this problem. As a result, back then many Afghans still went after the Russians using World War I era bolt action rifles firing a larger .30 caliber (7.7mm) round. The Afghans knew their best opportunities against the Russians were with long range sniping, not by getting close enough to spray them with automatic fire from the AK-47 (which fires a bullet with about as much stopping power and range as the M-16.) The U.S. Special Forces, because of their large budget for "trying anything" are experimenting with several different solutions in Afghanistan. In addition to the higher power 5.56mm bullets, they are using M-16s modified to take full power 7.62mm bullets and somewhat smaller 6.8mm bullets. They are also mindful that Afghanistan is a special case, and that most infantry battles still take place at ranges under a hundred meters. At these ranges, the current M-16 and M-4 weapons are still very effective.