Much effort has been wasted over the years by attempting to associate the range at which game is shot with ethics. In truth, there is no ethical dilemma associated with the competent shooting of game at long range. There is however a strong ethical dilemma associated with wounding game through incompetent shooting, regardless of range. Therefore there is no association between ethics and range, but ethics are closely related to competence.
At the range, you should be able to demonstrate, preferably on demand, what you intend to do in the field, under similar conditions, but you should not attempt in the field, what you have not been able to prove at the range. An accomplished long range shooter restricts the range of his shooting based on the immediate conditions he faces. The less experienced rifleman/hunter is less likely he is to understand his own limitations under any given circumstances.
Often we hear that a hunter need only hit a pie plate size target to take game, but a clay bird is a better sized target to establish a hunter's maximum range to engage game, and this gets us away from the shooting groups "trap," which has little to do with shooting game.