For all the documentaries and such about the 1960’s Gyrojet “rocket gun,” this is the first time I’ve seen rounds fired with this sort of clarity. The rounds cost $200 each… which once again makes me wonder why someone hasn’t decided to put them into production. If there’s a market for them at $200 each, you can bet there’d be a market for them at $20 each. And the thing is… they’re not that complex. I imagine the biggest thing holding back someone from making them is legalese and bureaucracy… many layers of government to jump through to build and sell something that I’d bet good money the US FedGuv would slap an ITAR label on for no good reason, as well as whole armies of attack lawyers lining up to line their pockets the first time a round goes off course or rapidly disassembles.
A Gyrojet round is basically four parts: a body made out of machined or extruded steel; a base made of machined steel; a propellant grain; a conventional primer. The base might be manufacturable from modern ceramics.
11 responses to “Gyrojet in high speed/high rez”
I wonder if you could put some slight grooves in the launcher barrel to impart spin? Then you could get rid of the complex and variable nozzle machining and just have one nozzle where the primer is? It would make it cheaper and maybe more accurate?
Rifling would would make the weapon far more complex. As it is, the barrel could be a simple perforated sheet metal tube.
And if the nozzle was in the center, where would the primer be?
HK made some caseless ammo for an experimental assault rifle and it had a somewhat more sensitive explosive as the primer. You could just fill the centerline nozzle with that primer and it would act like a fuse.
It looks to me as if the centers of gravity of the projectiles are aft of the aerodynamic center. If you redesigned the projectiles so that the AC were aft of the CG maybe the rounds would be aerodynamically stabilized and wouldn’t even have to be spun. Then you could fire the rounds out of a smooth bore gun which would give them an added boost but may give a slight recoil.
Think of the hundreds of years of invention and experimentation which have produced today’s firearms. The Gyrojet hasn’t even had 1 percent of that.
Turning the nozzle into a primer might work, but that’d be an area requiring substantial development. The round-nosed projectile seems hollow. Fill it with lead.
One area in need of advancement is the propellant grain. Better propellant and a much better grain design could greatly improve performance.
What about compressed air as a kicker?
It takes a bit for the round to work itself up to lethal speeds.
This might be a good anti-drone round coupled with this set-up here:
https://hackaday.com/2024/04/11/the-aimbot-v3-aims-to-track-terminate-you/
Compressed air would increase the weight and complexity of the gun, defeating the purpose. Additionally it would add recoil.
An issue with this is that the rocket motor in the round, as presented, is firing for quite a way down range, far past the barrel, imparting more spin/stability as the round accelerates. If you want to do all the stability within the barrel length, you also want virtually all the propulsion to occur in the barrel, and, essentially, you end up with a need for an essentially explosive propulsion system, which is already more easily obtained using a standard bullet & casing.
I wonder if you need a nozzle at all. Just leave the butt end open with propellant inside and some primer buttered on the end? You might have to use a hotter propellant but it would really simplify things.
Yes, you need a nozzle. Without a nozzle all it’ll do is sit there like a flare.
I dunno. I would at least try it.
We are running out of everything. Lead, antimony (which is alloyed with lead to make bullets), copper for jackets). But you could make gyrojet projectiles out of carbon steel or maybe even aluminum of which there is plenty. So the gyrojets best days may be ahead.
https://www.visualcapitalist.com/forecast-when-well-run-out-of-each-metal/
If that is your concern, you can make small arms bullets right now out of steel and use a driving band of copper like the big boys. It would be more expensive than current designs, but not 200 bucks a round (or even 20 bucks) more expensive.
But we’re not really running out of lead or copper. They are just getting more expensive because of the increased demand due to electrification of a lot more things.