350 Legend does nothing for me.......
If you are a reloader a re-barrel to 6x45 may make sense at some level.
I suggested a 6mm cartridge that uses the Legend case. It supposedly holds 35 grains of water which is 5 more than the .223 Rem.
Velocities claimed from BC Precision web page.
58g v-max 3528fps
85g Speer BTSP 3015fps
90g eldx 2826fps