What is M.O.A.?

M.O.A. stands for Minute of Angle. 20 M.O.A. or Minutes of Angle is equal to 1/3 of one degree.

How far will Zero or 20 M.O.A. allow me to shoot?

Zero M.O.A. is generally used for shooting 0 – 500 Yards depending on your scope and caliber

20 M.O.A. is generally used for shooting 600 – 1000 + yards depending on your scope and caliber

At 100 yards, one M.O.A. is about 1″ (slightly more).
The scope mount pointing down hill with 20 M.O.A. will allow you to zero your gun at a greater distance.

At 600 yards, a 20 M.O.A mount will point the scope down or point the barrel up depending on your perspective

One M.O.A. = 1″ at 100 yards or 6 inches at 600 yards x 20 M.O.A. = 120 inches at 1000 yards

20 inches points the scope down 200 inches

For Example:

650 yards with a .308 caliber and your scope centered (middle of adjustment), A 20 M.O.A. mount will be right on.