Gyrojet video


#1

This was posted on Youtube about a week ago. Interesting.

#2

Every time a video presenter fires off some of these rare cartridges of finite quantity, they become a little bit more valuable.


#3

That’s a great video, especially with the slow-motion, high-definition shots of the spinning rockets going downrange with fire coming out of their nozzles. They really explain in just a second or two the Gyrojet principle Robert Mainhardt and Art Biehl invented. Even more interesting is the spectacular (to me anyway) video of a Gyrojet rocket blowing its primer. Either the primer crimp was not good (not likely) or the propellant grain, or a piece of it, somehow moved back in the case and clogged one or more nozzle ports, causing the internal pressure to become so great it just blew the primer out; the first time I’ve ever seen this. The primer vent became a nozzle port.

The guys who put the video together contacted me beforehand and I gave them some information and a couple of “helpful hints.” I appreciate their plug of my book in the video.

Prices for Gyrojet rocket ammunition is now crazy. I have always maintained that a mint-condition, bright, clean 13mm Gyrojet rocket, wadcutter or roundnose, is about a $55-65 item. Value drops when the cartridge has a dark patina, some rust (all of them are copper-plated steel and sometimes small areas of the copper wear away), etc. A fired rocket is worth about half that and some fired specimens look like new. MBA fired a lot of them in test fixtures to measure things, and with no damage.

I’ve always thought that the best indicator of what something is worth is the price paid between a willing buyer and a willing seller, and the best place to find that price is a public, well-advertised auction like Pete deCoux’s and Vic Engel’s. Multiple auctions of the same items over time are a great indicator of consistent value. Price “guides” are nice, but they don’t buy the cartridges you are trying to sell. In two recent auctions (2016 and 2017) by Rock Island Auction, two full 24-round boxes of 13mm Gyrojet rockets were offered in each auction, several months apart. All the cartridges were mint, bright, and shiny. One box of 24 sold for $4,025 ($167.70 each) and another sold for $5,175 ($215.62 each, a world-record as far as I know). In the other auction, one full box sold for $2,185 ($91.04 each) and the other for $4,600 ($191.67 each) the average for all 96 rounds was $166.51 each, $100 more than I would value them at the high end. Of course, something has to be added to the value for the cardboard box itself, maybe $100-150 tops. I love the fact that the guys who did the video were willing to expend a few rockets, so we could all see how they did. I sent the guns’ owner a little “care package” in appreciation.

BTW, the NRA’s “Guns Guru” has a similar video comparing a Gyrojet Mark I Model B 13mm pistol with a .38 Dardick Special Model 1500. The Gyrojet pistol and ammunition were mine, on loan to the NRA because the Gyrojets in the NRA museum have been inerted and can’t shoot anything (a long story, involving the ATF). The Gyrojet pistol and 13mm ammunition did well, but the Dardick laid an egg, not even firing. Since I’m writing a book on Dardick Trounds, I’ll probably request a re-test with my pistol and my ammunition


#4

Indeed, the video is the best of the many on Gyrojets, and thanks to reference to Mel’s book and research they seem to have gotten the facts right.
In addition to the very interesting shots of the rockets in flight, the side views showing the action of the hammer striking the nose of the rocket and then being recocked as the rocket exits the barrel really helps understand the mechanics.

Many thank to Mel for supporting this video effort, and of course for his superb research and writing of the Gyrojet book, which EVERYONE interested in ammunition of any type should own and read to grasp the extreme “out of the box” thinking which can sometimes be associated with ammunition.


#5

This whole video is outstanding - watched it a couple of times. The technology of the cameras capturing the shots from the guns and the projectile movement are amazing. The guys are pretty low key so that helped and they do a good job of the technical analysis of things as they work (or should work). I think Mel helped a whole lot there.

Very intrigued by the flameout boost after the first 5 meters (?).

Like the combustible case (caseless) concept, I still think the stabilized gyrojet is a very doable and solvable technology. Oh, to have the time, energy & money to play around…

Would have liked to see some of the “carbine” length projectiles fired & recovered. Could you imagine them filming a 30mm launch? (Firing?)

Anyway - nice!


#6

Somewhat related, rocket boosted shells