40x46SR TP-DNT M781E1

Does anybody have propper images or documentation on the recently adopted/ordered 40x46SR TP-DNT M781E1?
DNT stands for Day Night Thermal. Means it has (to what I understood in the past) a 2 component filler in glass capsules which reacts upon contact (caused by launch or impact). Capsules are provided by the well known Cyalume (my last info was).

So far I have only a low quality image from an NDIA report.

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EOD - The M781E1 is a pyrophoric payload, not Chemillume. The pyrophoric is a highly process iron. That we the glass ampule breaks the iron oxidizes at thousands of degrees and instantly. This happens in milliseconds. heat and light output.


Jay, very interesting! Never heard of this system.
Is there more to read or see about?
Does this system/mixture have a name?


I have to be careful here, I am under a couple of NDA’s. I saw this demo in the picture. The ampule tip was broken and this is shaking it out. The stuff looked like graphite powder in the ampule. The exposed ‘graphite’ would slowly simmer if held upright with the glass tip broken off. If poured out it does what you see here or if impacting the ground you would get something similar.

Here is from one website - Iron based reactive powders that spontaneously ignite and burn when coming into contact with air. Pyrophoric payloads currently being produced for the 40mm DNT M918E1 High Velocity and M781E1 Low Velocity cartridges.

Advantages include:

  • High visibility day (unaided eye) and night (thermal & IR) past 1,500 meters
  • No explosive ignition
  • Non-dud range safety
  • Reduced fire risk
  • Extended shelf life (20+ years)

Jay, interesting!

I wonder about the reduced fire risk here.

And keeping it inside a glass ampule and away from air makes the ammo items quite sensitive no?
I understand you are limited by NDAs. Wish I saw the test results of flammability tests and cartridges stored in boxes simulating cracked ampoules etc.

Does a patent exist maybe?

Anyhow good to know this stuff is used. I assume it is just a question of time till details will surface.

The big driver was the 40mm M918 which is a Flash, bang and smoke with a M550 Fuze - mechanical clock like mechanism. The fuze was prone to duds and UXO down range. The Army wanted to get away from the fuzed round because of the duds and the UXO issue. The fuzes were expensive so the, the M918 and M918E1 are similar price. The low velocity M781 tagged along for the ride in technology advancement. I’m still unsure if the increased price for low velocity will be prohibitive.


No NDA for me so I will speculate. This looks like it might be a variation of nano-thermite (nanoparticle thermite or similar compound). Perhaps with a more reactive metal, such as sodium to ignite spontaneously in air. Of course, I could be wrong.

Below is an older link (2014) on funding direction with a bit of discussion on DNT 40mm grenades: https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2014/armaments/WedPaulHill.pdf
There is also some interesting info on LW30mm TP-Spotter rounds using a pyrophoric spotter compound.

Jay, it seems the price is not always the main criteria and of course we saw ridiculous stuff having been puchased (of course, it is easy to spend other’s money when not being held responsible).

Larry, thanks!
I still wonder what the statement on the “reduced fire risk” is.