I apologize for nit picking, but I don't want someone who doesn't understand what an MOA is to be confused by your approximation. I understand that you know what you're talking about and it works for you.According to the NSSF.
A Minute of Angle (MOA) is an angular measurement. A MOA is 1/60th of a degree. 1 MOA is a different size at different distances, 8″ at 800 yards is still just 1 MOA.
I agree with that definition. Ballistic program say hold .3 left. The bullet will travel 1.88" right at 600 yds.
I'm and have been talking about group location by doing the math. Dead on at 100 how far does spin drift move the POI at 600. Not by the definition a MOA.