Weapons: <b>September 11, 2003</b>

September 11, 2003

U.S. Army weapons designers are seriously looking into adopting a new cartridge for their rifles and light machine-guns. Experts are looking at replacing the current 5.56mm round with something between 6mm and 7mm. This search for the perfect caliber, is something that has been going on for over a century, since modern bullet propellants ("smokeless powder") was developed in the late 19th century. Back then, most nations quickly settled on calibers between 7.5mm and 8mm (or .30 and .31 caliber as the U.S. and Britain put it.) The Japanese and some European nations selected the 6.5mm cartridge. While not as powerful as the larger cartridges, the 6.5mm was easier on the troops (less recoil and lighter to carry) and, as far as anyone could tell, just as lethal. During World War II, when the Germans developed the first assault rifle (the SG-44), the developers concluded that the optimal bullet size would be 7mm. But this would have required too much new manufacturing equipment, so a "short" version of the standard 7.92mm rifle cartridge was adopted instead. The Russians, who designed their AK-47 right after the war, used their "short" 7.62mm round. This cartridge had been developed during the war for the SKS carbine. When the United States reacted to the AK-47 in the late 1950s, they adopted a military version of the civilian .223 Remington (a high powered .22 caliber round used by hunters for small game.)

This 5.56mm round created some controversy regarding it's ability to stop enemy troops. But against the smaller Vietnamese troops, the 5.56mm seemed to knock the enemy soldiers down quite effectively. Reports kept coming in that against determined men of larger stature, the 5.56mm did not "drop" them as effectively as the older 7.62mm rifle round. Keep in mind that, on the battlefield, the main idea is not to kill the enemy, but to take the fight out of him. Thus the term, "knock them down" is often used by combat veterans. If the downed enemy trooper is only wounded, but no longer fighting and maybe making a lot of agonized noises to unnerve his fellow, all the better. In Afghanistan and Iraq, troops had plenty of opportunities to see how effective 5.56mm and 7.62mm bullets were against enemy troops,. While all American assault rifles and light machine-gun are 5.56mm, sniper rifles and medium machine-guns use the older, and more powerful, 7.62mm round.

For the past ten years, there has been some pressure, mostly from the troops, to adopt a somewhat larger round. A major consideration for the troops, in addition to the better combat performance of the larger round, is weight. The older 7.62mm rounds weighed 6.1 pounds per hundred rounds. The U.S. 5.56mm round weighed only 3.5 pounds. This makes a difference for infantry troops who have to lug around a lot of ammo. A 6mm or 7mm round would weigh in at between 4-5 pounds per hundred rounds, depending on the design of the cartridge. If the larger bullet was noticeably more effective on the battlefield, troops would not be too upset at hauling heavier ammo. The rumored favorite in the U.S. Army experiments is a 6.8mm round. In experiments going back half a century, there have been cases of higher speed 6.5mm rounds performing nearly as effectively as 7.62mm rifle rounds. So the 6.8mm may be a lighter bullet that does not generate heavy recoil (which makes aimed automatic fire difficult) and still "knocks them down" like the 7.62mm bullet.