Smart Grenade Launcher

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The 20mm shell of the OICW has been replaced by a 25mm shell.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.


  1. Am I the only one concerned about that ejection port on the left-hand side of the stock directly above the magazine? Are these things going to be issued only to people who shoot left-handed? Or is the drill gonna be (1) Ready, (2) Aim, (3) Fire, (4) Remove extracted cartridge from shirt?

  2. the OICW was terminated because of its massive weight, but does anyone know exactly how much the XM-25 is going to weigh? Also, in response to the first comment, no matter what they do, the XM-25 is almost ceartainly going to have ejection ports on both sides for ampidexterous use.

  3. I don’t get it. AS I recall froma Popular Science article years ago (like 5 or more), the OICW was like 40% lighter than a comparably equipped M16. So how is it that the saystem is cancelled for weight problems? Perhaps teh original ideas didn’t translate through the r&d? It’s too bad, I thought they finally had it right giving each individual guy the capability for heavy weapons, and smart heavies at that. Now we’re back to the ‘one guy has the 203 one guy has the 60 the other 2 have the 16s’ mentality of soldiering (sorry my frame of reference is Air Force SP fire teams) One last thought…is ambidexterity really necessary? Has someone looked at the numbers on this? Is it worth the engineering cost? And what’s to prevent a trooper from shouldering his rifle for right hand use and having an expended case fly out the left side anyway? I’m not too familiar with the set up with ambidex weaponry.

  4. Ragnarok: I never saw the PS article, so I don’t have any idea what they claimed at the time. I imagine that you’re right about original ideas not working as well as hoped in the real world. There was a lot of headway made during the R&D of the OICW, though, especially in the materials department. Those advances have been incorporated into the XM8 (the assault rifle part) and I imagine into the XM25 as well. It’s worth noting that the XM8 is still having trouble getting down to designed weight and that some parts have needed beefing up (notably the handguard which began to melt in some tests), which of course increases the weight. If the XM8 is having trouble meeting weight while using some of the technology developed for the XM29 OICW, just think how much trouble the XM29 would be having at this point. I don’t think the OICW is totally dead, just stalled awaiting a breakthrough of some sort. In any event, much of the development of the OICW is allowing the XM8 and the XM25 to be on the fast track today.

  5. Plus, as noted in my post, the 20mm shells in the OICW weren’t really up to snuff. Going to 25mm wasn’t really an option given the weight problems, but since the XM25 is a stand-alone grenade launcher, they could make the switch to much more effective ammo.

  6. I could shoot cans all day with this thing; nay, make that vending machines! Or even a propane tank vending machine! I hope this project makes it past all the funding cuts and bureaucracy crap that everything else gets axed by. This weapon can be be applied to far more situations effectively than the old 40mm system (flatter trajectory right?)

  7. I know I’m coming in late on this one, but I really think this is a big fix for the common grunt. The ‘smart’ rounds are excellent, and an airburst capability is a thing of beauty. The ambidexterity should work great, and the utility is amazing. The one thing that will need to be discussed is the issuing of a PDW, or a sidearm to the soldier carrying this. You will need a backup. Trust me, a squad cannot, I repeat, CANNOT carry enough grenade rounds. Grenades that can reach out to the ranges this will are one of the most utilitarian things you can imagine. I WANT ONE!!!!

  8. Ragnarock: Only the rifle aspect of the OICW was lighter then the m-16, the gun as a whole was much heavier. This is never the less imrpessive as the rifle of the OICW is comparable to a submachine gun in size, yet it is still as acurate (500 yards?) as the m-16.