Some call it 6mm-.223, so search both.
The BHW barrels are a 2-3 month wait, but they shoot really well, I think they are about $250. I don't know if Hoser is set up to make brass for the 6x45, but it is not hard to convert .223 to 6x45 with just a set of loading dies and a trimmer. Most guys like the 1:10 for the 90 and less and the 1:9 for the 100s. I'd be willing to bet there is a thread on the caliber somewhere here on COAR15 as well. Dandy little cartridge.