The effective range will vary with different hunting bullets. The 6.5 Creedmoor head stamp does not impart magical qualities of lethality to ordinary bullets that they do not have when fired from other rifles with 6.5mm bores. Keep in mind that the 6.5CM was designed to be a precision long range target round. There is a big difference between poking a hole in paper or cardboard and killing a large animal quickly and humanely. As many posts in this thread have pointed out, a 6.5mm bullet with adequate velocity will likely work very well at 500 yds or less. If I were intending to hunt a longer ranges, like 600 to 1000+ my 6.5CM and 260Rem would become target rifles and I would be carrying a rifle with larger bore (heavier bullet) and lots of oomph, probably a magnum. If I were intending to shoot at live animals over far distances, I would consider it an obligation to myself and the animal to use a rifle/cartridge/bullet capable of consistent lethal performance at those distances. The 6.5 bullets excel at a lot of things but they are still ruled by ballistics and gravity.