Guys have been doing 375’s and 357’s on 223 brass for a long time, as long as the blackout, and longer really. It’s a formidable round. Really not sure where Winchester plays in, other than they may have felt a need to reaffirm themselves in the ammunition & cartridge development market, and maybe separate themselves from their waning firearms business...

Maybe a little too late for the AR boom, to put it generously, however.

But what really doesn’t make any sense to me - why on Earth would they name it “Legend?”