Measure across your chest from nipple to nipple. Now measure from the top of your chest to your belt buckle.
What are those dimensions?
When you start out with 2-3 M.O.A. of uncertainty and factor environment and skill in the equation, you have a 50/50 chance of hitting your 12 x 18 target at 600 yards. If only a portion of your target is available, your odds go down further.
Start with 1 M.O.A. and your odds improve. I was just making the observation that 2-3 M.O.A. is not at all impressive.