I suspect any effort to fill any gaps in the NE line-up with new cartridges would come to nothing - because they would be NEW cartridges. The failure to the .500/.416 to set the Anglophile db fraternity on fire can, I believe, be put down to this. Loaded with a couple of lighter bullet-weights between 350 and 410 grains, loaded to the same velocities as the 450 gr, this calibre could be a wonderful all-rounder - but it probably won't happen.