25x40B XM25


Sadly I have yet to add one of these to my collection. However, I have noticed that two different case shapes are around. One has a relatively narrow belt (which I have seen at exhibitions), the other a very wide belt (which I have seen in photographs). Can anyone clarify the history of this? Which one is current?


In view of the lack of response, I’ve been picture hunting.

The pic below shows what I’m talking about. The one on the right is one I took myself at a military exhibition a couple of years ago, showing the narrow belt. This is the only case type I’ve ever seen on an actual example.

The one on the left is scanned from Small Arms Defense Review, and shows an example of one they saw being fired, also in 2010. There’s another pic showing lots of them, which they took at the time. Notice the much wider belt.

So, my question is, what’s going on here? I can’t imagine any one gun firing both rounds. Which one is current?


I am intrigued that no-one seems to have an answer. I recall that one prominent IAA member has displayed a comprehensive collection of 25mm grenade rounds, but I can’t remember who. Can anyone help by drawing this thread to his attention?



I can’t help much except to add the following question: There are 3 lines of text on projectile of the cartridge in question. The bottom line appears to begin with the letters ATW…, is this possibly the ID for the manufacturer/contractor and if made for the US might there be a listing for the contractor in a recent D.o.D. Ammunition Manufacturers and Their Symbols? If so who knows what information you might turn up.



You probably have seen this before Tony, but just in case.

globalsecurity.org/military/ … /m1019.htm



Thaniks for that, Steve. It confirms my view that the narrow belt was the original case, with the wide belt being introduced more recently. I’d love to know exactly when and why, though!


Tony, it seems that the first pictures and videos of the wide belt version has been published in mid to late 2010. I first thought that these were just exagerated graphics but they are for real.

These are the ones from the video:

This is from an ATK page (the brochures still illustrate the narrow belt version):

These pictures were taken at Modern Day Marine 2011 (Jason will surely dream with the ones in the back!)


Many thanks, Fede!