Getting technical a 2" MOA group at 100yards would result in a 10" MOA group at 500 yards in all practical information. exactly 10.47". It's not wrong it's just simplified for those that don't know. Good luck judging a 1/2" at 500yards with a standard rifle set up. Even if you had a rifle that shot holes in holes and was sub zero MOA at 100 yds the end result would be 10.47" chance of being off at 1000yards. That would depend on various circumstances and absolute perfect conditions. It's a 1.047 multiplier that's all it is for those that understand the basic concept.