A new kind of ammunition could reduce by up to 40 percent the weight that the average soldier or marine carries in combat, which can easily exceed 100 pounds in combat. This "cased telescoped" ammo replaces brass bullet casings with polymer ones to achieve considerable weight savings, making U.S. troops deadlier in the process.

For nearly two hundred years, rifles and pistols have essentially used the same technology: a bullet and gunpowder pushed into a brass shell casing. The technique is simple, cheap, and reliable, which is why it has lasted so long. The downside: while an individual cartridge is relatively light, the weight of brass adds up. Brass casing technology has remained essentially the same since at least World War I, patently refusing to adopt modern materials.

Now that may be about to change. The cased telescope technology developed by Textron Systems, promises to bring small arms ammunition into the 21st Century.



Unlike traditional brass casing technology, cased telescope technology seats a bullet inside a polymer shell casing, fully enclosing it in plastic. The use of polymer results in a 35 to 40 percent weight reduction. Another benefit is that the overall length of the polymer encased round is approximately 30 percent shorter than the brass-encased round.

Cased telescoped bullets can't be used in weapons that use brass shell casings, so Textron has developed two prototype machine guns to show off the technology. There's one in 5.56-millimeter as an alternative to the U.S. Military's M249 Light Machine Gun and one in 7.62-millimeter (see above) as an alternative to the M240L Medium Machine Gun. The 7.62mm Cased Telescoped System (CTS) machine gun weighs 14.7 pounds, with 800 rounds of ammunition weighing 31 pounds, for a total weight of 45.7 pounds.

By comparison, the M240L machine gun currently in service weighs 21.8 pounds, the ammunition weighs another 51 pounds, for a total weight of 72.8 pounds. That's a weight savings of 27 pounds, or more than the actual machine gun itself. The 5.56mm CTS achieves similar weight savings over the M249.

In tests this spring at the Kvarn Land Warfare Center in Sweden, Swedish testers fired 5,000 rounds of ammunition and discovered the 5.56 CT System achieved a 20 percent tighter shot grouping and required 30 percent less ammo to accomplish fire missions over the existing Swedish light machine gun. Swedish testers also rated it higher than Sweden's existing light machine gun (which is basically the Swedish version of the M249) in ease of maintenance, trigger operation, recoil reduction, and burst fire control.



In addition to making prototype guns to test the ammo, Textron decided to develop a replacement for the current 5.56mm M4 carbine using modern ballistics technology. The 6.5mm Carbine Weapon uses a slightly larger diameter bullet, 6.5mm versus 5.56mm, and uses a 20-round magazine instead a 30-round magazine. Developed from a commercial bullet design, the low drag 6.5mm round is deadlier than than the 5.56, shoots farther and flatter, and performs at near machine gun levels. The Carbine Weapon also uses a piston-based operating system, which runs cooler and prevents overheating in sustained firefights.

Current small arms tech has largely plateaued, resulting in weapons that incrementally better than past designs. Today's M4 carbine, for example, is merely a derivative of the original M16 rifle. There have been little, if any game-changing technologies introduced over the past fifty years. Cased telescoped technology, along with the adoption of a new bullet, would make soldiers not only more lethal but more mobile as well. It seems the plastics revolution will be hitting the world of bullets just a little bit later than everything else.

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