Looking at some recently published load data from Sierra, the 77gr data is pretty much the same as we have been using in the .223. Other than using the really heavy bullets at mag length, I don't see the point of the Valkyrie.
I mean, from all that I’ve seen, you are generally talking about 100fps faster than a hot 5.56 load as near as I can tell in the 75/77gr range.
Pulling up the barrel length tests, the federal 75gr TMJ is a muzzle velocity of 2912fps out of a 20” Barrel. And that is one with no gas system.
IMI 77gr razor core 5.56 is about as hot as it comes. Ive seen about 2790-2820fps average velocity out of a 20” barrel depending on the test gun from what I can find searching around.
Basically you can launch really heavy bullets and that is about it. 5.56 loaded on the hot side is damn close to factory .224v loadings. Now maybe it’ll prove out that 224v can really tolerate being loaded 100 or 150fps faster than it is being loaded now...but...
Most of the comparisons I see are using .223 Remington 77gr loadings which are likely loaded to more like 2650-2700fps at the muzzle and the same with Grendel comparisons they seem to be using weaker/lower BC loadings when doing comparisons.
Against hot 6.5G and hot 5.56, 224V seems to have an edge in ultimate long range performance (except 6.5G in wind drift which I like to bring up), but that is mostly because of those 90gr pills. Which ain’t nothing...but if you want to load lighter bullets the performance difference is small (and if you want to load lighter, 6.5 grendel is massively better when loading lighter pills in it than in 224V)