An interesting presentation on the “Ring Airfoil Grenade” concept from some decades ago. This was a “fat” ring-wing that would spin in flight; the result was a flatter trajectory than you’d get with a traditional bullet-shaped grenade. The presentation includes a large number of diagrams and photos of various types of grenades and launchers. Some were made from steel, pre-scored and filled with high explosives; others were made of softer materials and filled with CS capsules. Upon impact, the high spin rate would cause the projectile to split open and spew out the tear gas; and all that would be left is a rubber ring of no particular tactical value to the rioters. The M234 RAG launcher was actually used in the late 70’s into the 80’s, though it seems pretty much forgotten now.
The aerodynamics of the RAG seem interesting. Difficult to envision what the technology could be used for apart from various types of grenades, though. The “cookie cutter” armor piercing system certainly seems interesting.