MOA SFP Question

[kevin11mee]

A question regarding SFP scopes. I understand that the reticle is not correct if the scope is not at its highest magnification, but can the numbers be halved when at half magnification? For example, if I'm supposed to hold 4 MOA for wind shooting a 4-16 scope, is it correct to hold at 2 MOA if on 8 magnification?

 

[4ester]

Yes that’s technically correct.


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[SomeJackassOnAForum]

So, yes and no.

The equation is:

Max Mag x Value = New Value
Current Mag

So 2 MOA hold on a 20 power scope at 20 power, is:

20 x 2MOA = 2MOA
20

at 10 power it's

20 x 2MOA = 4MOA
10

The problem is that in the world of scopes, exactly what power you're at may not be what it appears to be.

The 3-10x42 is probably the most common scope on the market, sometimes called a 3.5-10, but these scopes are usually really 3.5-10.5 or 3.33-9.99. Is your 3.5-18x50 really a 3.5-17.5x50 or is it a 3.6-18x50?

If you're doing a big adjustment like "half" and you're trying to get a rough measurement for a windhold, you'll probably be ok, but be careful about trying to do things like game holding a 10 power scope at 8 power to up your holds by 125%.

 

[83cj-7]

My technique to “true” your holds for reduced power:

-On a blank piece of paper or cardboard, draw about a 1/2” dot.
-Measure up or down 10.5” and make another 1/2” dot.
-Place the target at exactly 100 yards.
-Setup rifle securely on a bench or ground
-With scope at max power, put crosshairs on top dot. (10 MOA hold should line up with lower dot)
-Carefully reduce scope magnification until the 20 MOA hold is on the lower dot.
-Mark power ring, that is now your magnification for holds to be doubled.

You will notice that I specified 10.5”. That is because 1 MOA is actually 1.047”. 10 MOA x 1.047 = 10.47”

Hope this makes sense.
Travis S