November 1, 2010:
After yet another year of testing and tinkering, the U.S. Army is finally sending some of its high-tech, but long delayed, XM-25 grenade launchers to Afghanistan. This was supposed to happen two years ago, but testing kept revealing things that needed to be tweaked. The first troops to get the initial five XM-25s will be paratroopers. Another 36 will quickly follow if there are no problems with the first five.
In development since the 1990s, the revolutionary, XM-25 grenade launcher is finally going to see some combat. These will be the final test prior to mass production, and distribution to the troops. It was five years ago that six XM-25s were delivered to the U.S. Army for troop testing. Last year, a few were sent overseas for testing in combat situations. While the troops have been very enthusiastic about the new weapon, there were a lot of suggestions, mostly about minor items. So the army kept tweaking and refining the weapon.
The XM-25 was originally one of two weapons (the other being a 5.56mm rifle) incorporated in the 8.2 kg (18 pound) XM-29 OICW (Objective Individual Combat Weapon). The OICW was originally developed as a replacement for the 40mm grenade launcher, with the intention of giving the grenadier some rifle firepower as well. Didn't work out as intended.
The big problem was effectiveness. The 40mm rounds weigh 540 grams (19 ounces) each, the original 20mm OICW round weighed half that. This was one of the 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, especially compared to the 40mm shell it was replacing. 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 20mm and 25mm "smart shells" both use a computer controlled fuze. The XM-25 operator can choose one of 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 (19 foot) radius from the exploding round. 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 other modes are "PD" (point detonation, where the round explodes on contact), PDD (point detonation delay, where the round detonates immediately after it has gone through a door, window or thin wall) and "Window", which is used for firing at enemy troops in a trench, behind a stone wall or inside a room. The round detonates just beyond the aiming point. For buildings, this would be a window or door frame, cave entrance or the corner of a building (to get enemy troops thought to be around the corner.)
The XM25 is still a heavy weapon, with the final version coming in at 5.5 kg (12 pounds). The 25mm shells weigh over half a pound each (270 grams). On the plus side, there is already a 25mm armor piercing round (using a shaped charge capable of penetrating over 50mm of armor) available. This makes the XM-25 capable of knocking out light armored vehicles. Then there are the new versions of 25mm round, like fuel-air explosive (or "thermobaric"). 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. This gives the attacking troops an opportunity to rush in and kill the enemy, or take prisoners. In combat, every little advantage helps. With the XM-25, hiding behind rocks, trees, walls or in caves will no longer protect you. There is also a flechette ("shotgun") round. The magazine holds four rounds (which cost, on average $35 each), while the XM-25, with its 4x thermal sight, costs $25,000.
Meanwhile, earlier this year South Korea got its first export customer for its similar K-11 20mm infantry rifle. The UAE (United Arab Emirates) ordered 50 of the $14,000 20mm/5.56mm weapon, to try them out. It was two years ago that South Korea revealed it had developed the K-11, which appears to be identical in concept of the U.S. Army XM-29 (or OICW). The South Korean version weighs 6.1 kg (13.4 pounds) and combines a 5.56mm rifle, with one firing 20mm computer and laser controlled shells. The South Korean weapon appears to operate the same way as the 20mm shell of the XM-29. The South Koreans plan to issue the K-11, on the basis of two weapons per squad (an infantry unit containing 10-12 men). The K-11 is about 25 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 Koreans have found that the 20mm smart shell is effective out to about 500 meters.
The appearance of the K-11 may have encouraged the XM-25 developers to finish up and get the weapon into the hands of the troops.