Despite the way the U.S. M-1 dominated the battlefield during the 1991 Gulf War, research on the next generation tank is backing away from an "improved M-1." The M-1 was outstanding in the Kuwait desert because that was the perfect terrain for the 120mm gun of the M-1 and it's state of the art fire control system. While military planners (using past experience) expected U.S. gunners to hit about 70 percent of targets 2,400 meters away, American tank crews did better than that, and regularly destroyed enemy armored vehicles 3,000 or more meters (two miles) away. What is worrisome is a weapon that has been around for nearly two decades, top attack warheads. This weapon flies over the tank and detonates a shaped charge (generating an armor penetrating bolt of super-hot plasma) that goes through the thinner top armor on the tank. Not yet used in combat, the top attack warhead has performed well in years of tests. Top attack warheads can be defeated by reactive armor (blocks of explosive that use their blast effect to cripple the bolt of plasma), but nothing makes a tank completely safe from top attack. As a result, more interest is being shown in lighter, faster tanks and more missiles. Iraq has been rumored to be buying top attack missiles on the black market and smuggling them in. If this is true, an invasion of Iraq would provide combat experience with top attack missiles versus M-1s. If a number of M-1s are lost, military planners will be under a lot of pressure to move away from the super-heavy (nearly 70 tons) and well protected tank (like the M-1) and towards more missiles.