Weapons: 25mm Grenade Launcher Rises From The Dead


October 2,2008:  The U.S. Army has a new, lightweight (12 pounds) version of its XM-25 grenade launcher, that, after over a decade of development, is to be field tested to see if the new model works. This is an interesting development in light of the fact that three months ago, South Korea revealed that had developed a similar weapon, the XK-11. This weapon appeared identical (in concept) to the U.S. Army XM-29 (or OICW, for Objective Individual Combat Weapon) that preceded the XM-25. The South Korean version weighs 13.4 pounds and combines a 5.56mm rifle with one firing 20mm, computer and laser controlled, shells. The 18 pound XM-29 was developed, in the 1990s, as a replacement for the 40mm grenade launcher. The 40mm rounds weigh eight ounces each, the 20mm OICW round weighs 3.5 ounces and the new 25mm shells about five ounces each.

But there were several major problems with the OICW. It was too heavy and ungainly, and the 20mm "smart shell" it fired did not appear capable of effectively putting enemy troops out of action. So, in August, 2003, it was decided to take the 5.56mm portion of the OICW and develop it as a separate weapon (the XM-8) and develop the grenade launcher part that fired the "smart shell" as the XM-25. But the XM-25 would use a 25mm shell, which would generate 50 percent more fragments (and heavier ones at that) than the 20mm shell of the OICW. The XM25 was expected to reach the troops by 2008. But that didn't happen, as tests were disappointing.

The 20mm and 25mm "smart shells" use a computer controlled fuze. The XM-25 operator can select four different firing modes via a selector switch on the weapon. The four modes include "Bursting" (airburst). For this to work, the soldier first finds the target via the weapons sighting system. The sight includes a laser range finder and the ability to select and adjust the range shown in the sight picture. For an air burst, the soldier aims at an enemy position and fires a round. The shell is optimized to spray incapacitating (wounding or killing) fragments in a roughly six meter radius. Thus if enemy troops are seen moving near trees or buildings at a long distance (over 500 meters), the weapon has a good chance of getting them with one shot. M-16s are not very accurate at that range, and the enemy troops will dive for cover as soon as M-16 bullets hit around them. With smart shells, you get one (or a few) accurate shots and the element of surprise.

The 25mm shell in the XM-25 provided some more options, and, it is hoped, more lethality. The US has fired over 30 million 25mm shells from the cannon on its M-2 Bradley armored vehicles and was satisfied with the lethality of that shell against infantry. One of the new options with a larger shell is a fuel-air explosive (or "thermobaric") version for the XM-25. Such a shell would cause greater blast effect in an enclosed space, and actually suck most of the oxygen out of a cave or closed room long enough to make surviving troops at least a bit groggy. In combat, every bit helps. Other specialized rounds would be for breaking down doors (HESH), or penetrating armor (shaped charge).

The South Korean XK11 appears to operate the same way as the 20mm shell of the XM-29. The South Koreans say they will issue the XK-11 in two years, on the basis of two weapons per squad (an infantry unit containing 10-12 men). Each XK-11 costs about $16,000, which is 20 percent cheaper than the XM-29. It's unclear if the South Koreans found solutions to the problems the XM-29 and XM-25 encountered, or simply developed an improved XM-29 and decided it was useful in small numbers. The South Korean announcement made no mention of those American weapons.

The new version of the XM-25 has numerous design improvements over the prototype that showed up four years ago. Lightweight components got the overall weight down to a manageable 12 pounds (with a four round magazine, a ten round magazine is in the works as well). Improvements in the electronics and the ammo increased the range (500 meters for point targets, like a window, and 700 meters for area targets, like a group of men.) The actual "feel" of the XM-25 has been modified by thousands of hours of troop handling, and paying attention to what the troops had to say. The next goal is to see if the troops actually find it worthwhile lugging around in combat. The current plan is for one or two men per ten man squad would have an XM-25, but only if the weapon proves worth the weight on the battlefield. Useless weapons get left behind or "lost." Each XM-25 will cost $25,000. Each 25mm round costs $25. Even if the XM-25 survives more troop tests, it won't enter regular service for another six years.





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