Rocket/Gyrojet related?

Here is an item I picked up a number of years ago in a lot of miscellaneous junk ammunition components. At first casual glance I thought it was just a bullet jacket and tossed it back in the junk box. Recently I got to looking at it a little close and it appears to me it may be some type of rocket/Gyrojet projectile.


It’s about 7.95mm in diameter and is attracted to a magnet.
The base/nozzle has what appears to be slanted holes it impart spin.

Any thoughts on it would be welcome.



Your cartridge is in fact an MBA .30-caliber Gyrojet rocket, recovered after being fired. It was one of a series of “Delay-Fuse Gyrojets” designed to be dropped in large groups from aircraft flying over the jungles of Vietnam. As they were being ejected in canisters from the aircraft, a sheet igniter lit long pyrotechnic delay fuses on the back of the rockets as they fell to the ground, where the delay fuses continued to burn toward the rocket’s base with exposed nozzle ports, through which the rocket propellant was ignited after hours or even days. Then the rocket fired with a bang in a more or less horizontal trajectory, depending on how it was laying on the ground. The idea was to surprise and kill enemy troops long after the aircraft was gone. When a group of these fired, it sounded like a fire fight. The middle hole in the base was not for a primer: It held a small nail which secured the delay fuse to the rocket. They actually worked, sort of, and passed the Army’s test. But they were not deployed operationally. All the variations of these are covered in my Gyrojet book in Chapter 9. Here are two pics of your rocket before it was fired, one without the delay fuse and the other with it, protected by a fiberglass covering.



Interesting, are these fired examples common?



No, not common at all. You have a prize. But keep in mind that Robert Mainhardt - the “M” in MBA - never threw anything away. He saved everything and later gave fired Gyrojets of all types to MBA headquarters visitors as souvenirs. He also included them in catalogs at $1 each. Here’s a pic of some more fired and recovered .30 Delay-Fused rockets. The nickel-plated one blew my mind because I had always thought that nickel-plated Gyrojets were dummies., obviously not in this case.

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The ingenuity of the MBA team is just mind boggling.
Well done to Mel for his superb research and writing on the subject.

Everyone should get a Gyrojet book, just to broaden your horizons on the incredibly broad spectrum of “ammunition” capabilities, uses, options and manufacturing options. The “who, what, why, and how” are amazing to contemplate.