not familiar with what rifles are currently chambered in that cartridge, but the cartridge is definately interesting... my retired machinist buddy just built a single shot from scratch, & his 1st load recipe he tried, put 3 shots touching at 100 yards, after he got the scope dialed in...
IMO, 400 yards might be pushing the limit of the cartridge... but that's based on my general observations of the cartridge, not by any practical exprience... with the right bullet, & a barrel with the proper twist rate for those super slick bullets, it might suprise me & be pretty good at 400 ???