This is a discussion on The Tueller Drill/21' Rule Revisited, IDPA style within the Reference & "How To" Forum forums, Join Date: Nov 2005 . People should know that IDPA accuracy is all things being relative quite fine.
Allen's rule revisited: quantitative genetics of extremity length in the common frog along a which states that the relative extremity length decreases with increasing latitude. . whereas the corresponding date for the northernmost population