XM-25 Tested With Smarter Shells (Feb 20, 2004 entry)
Strategy Page has a must-read post on the development of the M25 grenade launcher. This isn’t your daddy’s M203.
Regular MO readers will know that the XM29 OICW was scrapped and the two elements of that weapon, a 5.56mm assault rifle and a 20mm grenade launcher, went on to be developed as separate weapons. The XM8 assault rifle is in the advanced stages of testing as we speak. The XM25 smart grenade launcher is lagging, but should be ready for initial testing late this year or early next year.
The 20mm shell of the OICW has been replaced by a 25mm shell. The 20mm was originally adopted because the weapon and the ammo would be lighter, and the weapon was too heavy as it was. The XM29’s weight was a major factor in its cancellation. Splitting the grenade launcher off into its own weapon allowed the step up to the 25mm shell, which increases performance by about 50%.
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”) shell 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.
The 20mm and 25mm “smart shells” use a computer controlled fuze in each shell. The M-25 or M-307 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. This 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 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.)
While the XM8 is basically nothing more than an incremental improvement to existing assault rifle technology, the XM25 is a great leap forward for individual fire support.
The 25mm shell for the XM25 was originally developed for the XM307 grenade launcher, which is to replace the current 40mm M19 grenade launcher found on many vehicles, especially Humvees and Strykers. The XM307 has a much longer range than the M19, and it’s more accurate and lethal. Good stuff.
UPDATE: Strategy Page made a seperate page for its XM-25 post here. I quoted part of it in my post, but if you want to know about the weapon you really need to go check out the SP article. (I wish that SP would have permalinks to each post all the time. They put such consistently good stuff every day.) They also have the same pic I used, which I found on some Japanese-language site. There don’t seem to be many XM25 images out there yet.