The 224 Valkyrie hasn't cured cancer yet, but from the hype, you would think it has.
Since it's whole conception was based on it being a round for a semi auto gas gun, not too many bench shooters pay much attention. It looks like it will do just about anything a 22-250 will do but with a smaller bolt face.
The twist rates they advertise seem sort of skewed. A 100 grn 22 caliber bullet it would seem, would require a faster twist than 1-7, especially at the BC numbers they are touting. But that seems to be what people are using.
My brother has a AR chambers in 6.8 SPC, and is thinking about getting a Valkyrie barrel for it to shoot the 90 grn load.