Chinese Silver Iodide Projectile


On the CBS News, either Monday or Tuesday, they showed a twin-barreled gun of about 40mm firing projectiles containing Silver Iodide crystals in an effort to make it rain to help clear the smog for the Olympics. Does anyone know more about this cartridge and projectile?


IAA member (board member), Mel Carpenter can certainly speak to MBA’s (“gyrojet” folks of years past) efforts with “cloud seeding” cartridges…I have found quite a bit of “rain making” (cloud seeding) info via the


Pepper-Apparently this is not a new program to use artillery for cloud seeding in China. Here is an article showing the gun, which turns out to be 37mm, not 40mm, and a TP version of the cartridge that dates from 2006. The actual projectile appeared to be a black, but CBS only showed about a 2 second view of the cartridges, so I can’t be sure. … rain_x.htm


That is really cool! Especially since it does not seem to cause any chemical pollution issues that effect the environment when used. Wasn’t their a earlier thread here on the forum about rain making rockets using the same compound?

Anyhow, that is definitely a major special purposes round! I am going to have to call the National Hurricane Center down the road to see if they have a extra one hanging around. They were talking about seeding clouds last year for something. I think they tried it using aircraft launched devices?


The round shown, a 37x252R for the M39 AA gun, actually has the marking “AgI” which is the correct one for Silver Iodide.
The term “training round” there likely applies to an inert loaded instruction model.

Comparing the amount of AGI contained in a so called “anti hail rocket” I think it should be no problem to transport the same quantity with about three to five full clips of those 37mm.

An unusual approach though and probably typical Chinese - or just the utilization of thousands of outdated surplus guns and millions of reworked HE shells.


OK, I’ll rise to Pepper’s bait. Here’s a half-size image of the 40mm MBA gyrojet cloud-seeding rocket. It’s made of fiberglass, not steel, so shrapnel will not rain down on innocent civilians. The Soviets, and now Chinese, apparently have no problem with firing artillery shells and not worrying about where they might land after they function.

The point of all of these was to create rain by providing little pieces of condensation nuclei for water vapor in clouds to stick to to form droplets of liquid water. Silver Iodide worked well, and the MBA rocket carried 97 grams of it.

The MBA project was to prevent hail damage to crops by forming many small rain droplets instead of a few large hailstones.

The rocket was launched from an aircraft (Piper Aztec) with a side-mounted vertical launch tube, climbed 2,200 meters (7,200 feet) at Mach 1.1 while spinning at 50,000 RPM. When the delay train between the motor section and payload burned through, it lit the silver iodide “candle.”