Assuming the SFP scope shows 2 MOA between hash marks at 18 power, is it then correct that at 9 power, the distance between hash marks will be 4 MOA and at 24 power, the distance between hash marks will become 1.5 MOA? I think it also follows that a 1 inch target at 18 power and 100 yards will fill up 1/2 of the space between hash marks (1 inch out of the two inch (MOA) distance. But at 24 power, the 1 inch will take up 3/4 of the distance between hash marks (1 inch out of the 1.5 inch distance). Does this sound correct? I have a Viper HS-T 6-24 SFP on backorder and am considering its suitability for target shooting. The reticle is .15 MOA thick. I did a mock up and that dot size seems pretty good at 24 power in relation to the reticle. Thanks.

Before you become further entangled in working on the math, consider that you are using 9, 18, and 24 as references. 9 to 18 is not the same as 18 to 24 - you'd need to run it up to 27 to establish a linear relationship.

Ouch. You are right. Thanks. I had in my mind that 24 was 4.5 way from 18. It is actually 6 away. So, 18 to 9 is double the MOA size, 18 to 24 (6 difference) would be 2/3 the MOA size. 6/9 is 2/3 so instead of 1/2 (4.5/9) the 2 MOA distance at 24 power would be 2/3 the size in MOA units. Recalculated, Assuming the SFP scope shows 2 MOA between hash marks at 18 power, is it then correct that at 9 power, the distance between hash marks will be 4 MOA? And at 24 power, the distance between hash marks will become 2 * 2/3 = 1 1/3 MOA? That sound right to me, but then again, I screwed up the first time.

I used to work very hard trying to make sense of Mils, MOA, (depending n the scope, focal plane and reticle) using image magnification variables. It's a good way to drive yourself insane. In an active hunting environment you can spend so much time calculating and double checking your results that you miss the best opportunity to take the shot. I see verything in the scope from an MOA perspective (regrdless of the type of rectical) and I simplify MOA as 1 inch ... forget about the decimal. I know that my rifle will easily hold 1 MOA +/- (it's actually better than that) so I am confident I can hold on the kill zone center out to 400 yards with complete confidence, regardless of which power setting my scope is set at. Beyond 400 yards I rely on my dope sheet with full understanding that 1MOA is always 1MOA, relative to the distance to the target.

I think you're going at it backwards. My SFP scope reticle has hashmarks that measure 2 MOA at 16x, 4MOA at 8x, and so on. I switched to FFP, now 1 MOA is 1 MOA, no matter the magnification.

Here is the reticle that your scope comes with: To put it simply, at full magnification (24 power) is where everything is based on, so at 24 power, your subtensions will be 2 MOA. Therefore, at half magnification (12 power), the subtensions will be 4 MOA. Does that make sense?