300m plus with copper needs quite a bit of power to keep the velocity up. The BC's on the copper bullets are just not good enough to get out there and stay above 2400 fps which is the min velocity I am personally happy to trust monolithics down to - the fragmenting copper bullets might be different, I don't know yet. My 26" 280ai will get to 400m with an LRX over 2400 fps, as will 6.5 PRC, 7RM, 300WM, but the majority of deer stalking rifles in the UK today will struggle to deliver a copper monolithic with enough velocity to expand reliably much beyond 250m. Everyone needs to be running the numbers on their own chosen cartridge/bullet combination to understand what their new range limit is.