Free: Contests & Raffles.
Since everyone around here seems to hate the word “ethical”, grab a thesaurus and find another one - but set a standard for yourself. My standard is that at least 9 times out of 10, my first shot should be fatal. Compute the actual kill zone size of the animal you are hunting, and start shooting paper at longer and longer distances. When you can’t put 9 of 10 shots into the target, shooting under real life conditions (wind, angles, obstacles, etc.) shooting from field positions like prone, then you’ve found your maximum range. Few will admit it, but for the vast majority of hunters it is this side of 400.