Re: How an MOA is measured
First, get an understanding of elevation. Understand your ballistics for the particular round you are using. Okay. At 100 yards, your bullet will drop so much, then more at 200 and so on. Second, get an understanding of your windage. Again, know your specific ballistics for that particular round. The heavier (more grains) the round, the less windage you will incur, in most cases. Now, there are many threads on these 2 topics alone. Lets remove these topics and lets talk MOA. Most guys here have told you that the 1 Minute of Angle is 1.047 inches at exactly 100 yards. That is 2.094 inches at 200 yards. That is 4.188 inches at 400 yards. 8.376 inches at 800 yards, and 10.47 inches at 1000 yards. If the bore of your rifle shot a "laser bullet" that didnt drop, or didnt get affected by wind, it would be exactly 0 MOA at 1000 yards. Let that be the Center of the cone. Imagine a cone around that centers this laser shot. If you were off by 1.047 inches at 100 yards, then draw a circle around that first laser center shot, the bullet would be off 2.094 inches at 200 and so on til off 10.47 inches at 1000 yards. Keep drawing circles at so many x00 yards. This would be 1 MOA. MOA is a degree, like in 360 degrees of a circle. That circle would be proportionate at each x00 yard length. I hope this makes sense so far. Now you have your cone. You can see that in any direction you miss 1.047 inches, your cone proportionate to however many yards from that first laser center shot. Now, put your ballistics back in the picture, 1 -drop and 2- windage. 1 moa is considered decent in terms of long range accuracy. If you are 2 MOA off at 1000 yards you are off 20.94 inches in any direction from center.
TaDa - MOA