The military's problem is to send a heavy projectile at hypervelocities. Of course, something as light as a standard rifle bullet would merely splash on hitting a plate of tank armor. 30/06 bullet could be kept from disintegrating instantly when propelled at that velocity, it would achieve 270,000 foot-pounds of kinetic energy at the muzzle-equivalent to a ten-ton eighteen-wheeler traveling at 20 miles an hour. Using this technique, three independent laboratories have now produced velocities beyond 26,000 fps. As current flows between the rails, the moving magnetic field accelerates the bullet down the whole length of the barrel. The current forms a magnetic field behind the bullet. With a projectile at the breech between the rails, an electric current is applied. Its bore is different it has two parallel copper rails, one on each side. Like an ordinary rifle, an EMG has a breech, barrel, and muzzle. Writing in the March issue of The American Rifleman, Terry Metzgar reports that EMGs work like linear electric motors. ![]() In effect, they've traded a bang for a zzzap: they've come up with the Electromagnetic Gun (EMG). The military designers have set out to circumvent the limitations imposed by chemical propellants. You can stuff in all the propellant you want, and you'll not exceed that velocity a whit. Worse, though there are high-speed explosives such as Primacord or some plastiques with detonation velocities above 20,000 fps, there are physical barriers to driving an explosively propelled projectile that set in at around 6,000 fps. Chemical propellants cannot push a bullet beyond the speed at which the detonation wave propagates through the explosive and into the surrounding gases. The Soviet T80 tank, for example, is fairly well shielded against a round of that velocity and weight. At that velocity, the big projectiles literally melt their way through armor-but not through the newest, toughest armor. Tanks employ much larger tungsten-carbide projectiles driven at velocities in excess of 4,000 feet per second. The military projectile designers have to think big. It won't do for a tank commander sighting on an armored vehicle. That's adequate for a pot-hunter sighting on a caribou at a reasonable distance. The "aught-six" fires a 180-grain bullet (one grain weighs one seven-thousandth of a pound) with a velocity of about 2,700 fps, a combination producing about 2,900 foot-pounds of energy. 30 inches, giving its caliber, and was introduced in 1906, giving its suffix. ![]() ![]() This venerable cartridge has a diameter of approximately. The standard in hunters' ammunition is still the old reliable. Modern big game hunters typically rely on weapons of larger caliber but lower velocity, about 3,000 fps. 220 Swift, which produces muzzle velocities of over 4,000 feet per second (fps). In the 1930s, it seemed as if the ultimate had arrived with the. The problem of projectile velocity haunts military minds as well as hunters' dreams. With every hunting season, hand-loaders renew the quest to squeeze that extra bit of velocity out of their pet load.
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