Interesting Patent- US9021961: Finned 40mm Projectile

https://patents.google.com/patent/US9021961

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So the pusher spins and the grenade stays straight-ish?

Bet this applies to the new set of grenade-launched drones.

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Found this one for a finned, rocket propelled, guided grenade
https://patents.google.com/patent/US9746295B1/en

This one is neat too
https://techlinkcenter.org/news/the-army-has-this-idea-to-shoot-paragliding-drones-out-of-a-40mm-grenade-launcher

I mocked it up last night @bdgreen

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I’ve got an unknown field recovery that I picked up years ago on a former Ft. Sill test area. Looks like a 40mm recoilless cartridge, with a base kind of like a Swiss 20mm recoilless. Fin-stabilized, it looks as though the case flies with it. The only document I ever found even close to it was on a larger experimental item, if I recall it was either a 110mm or a 156mm. Got that pub around here someplace.

Swiss 20mm recoilless?

Unless I’m miss-speaking, trying to do three things at once and could have my wires crossed. 20mm, long tapered case, blow-out base?

20x180R Sweden M42?
But the projectile for these is very conventional, no fins.

I’m teleworking from home today, trying to catch up on the forum between work taskings and calls.

Correct, but the base is blow-out and has three supports to a central primer. This is similar. I’ll take some pics in a little bit, an unusual piece.

I know what you mean, it is the support for the central primer.
The projectile is a standard type.

Yes, but no…….

That is really cool! A combo of the US designed recoiless cases, the Swiss 20mm recoiless and gyrojets

I thought I’d seen something similar in a 156mm doc, but I was mistaken, it is in a 105mm rapid fire document.

Swedish, Swedish!

Sorry, my bad!

That 40mm now reminds me of the Canadian 3.2" Heller.

Source: internet.

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Continuing to tinker with my representation of the design in the patent. Thinking about actually scaling it to launch from the 37mm smoothbore flare launchers that are everywhere. Any bets on how far it would fly with just a shotgun primer :)


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With just a primer it is unlikely to leave the barrel.

I’ll have to up my power game then :)

I still need to model the sabot and pusher. Also, should I use springs on the fins, or something else to make them pop open? I could mold them into it (which I think just answered my question).

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