Originally Posted by C.O. Shooter
I believe you also can take your cosign and multiply it by your MOA and this will give you your adjustment!
500 yards = 9 MOA
20 degree angle = .94 cosign
.94 cosign x 9 MOA = 8.46 MOA or call it 8.5 MOA
I don't believe that this will give near the same result as multiplying the cosine by the yardage since the yardage is a linear function and the moa drop is a geometric function, I may be wrong, but I believe if you try to work the problem the two different ways you will get two different results. Only one of the methods can be correct if they give two different answers.
For example for my 6.5-284 the moa drop at 1000 yds is about 26 moa. 26 x .94 = 24.44. If I multiply 1000 x .94 I get 940 yds which shows up as about 23 moa on my ballistic chart. The results in a 14.4 inch differerence in POI and I will miss that antelope. The divergence gets even worse as you increase the angle.
The correct method is to multiply the yardage by the cosine for corrected yardage and use that yardage to get the moa drop from your chart or program. Of course some programs have a provision to enter the angle or cosine. Ballistic FTE on my iPhone does the whole thing for me automatically since the iphome has the capabilitie to measue angles from level and I have a bracket to mount it to my gun.