Posted: 3/14/2017 9:20:02 AM EDT
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I understand the concept behind FFP scopes and why people "want" them. It seems like you'd have an impossible time ranging at any of the lower or even mid magnifications because the reticle is so small.
I feel like it would be faster and more precise using a SFP scope with a clear reticle at 50% or 100% mag and doing some simple math. Can anybody with alot of experience elaborate? |
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With an FFP scope you can readily range at any power, as the size of the target changes at the same rate as the reticle when adjusting the power.
This is not true if the SFP scope; the reticle remains the same size regardless of the magnification. On the SFP, if you take the power you want to range with, and divide it by the power you're supposed to range with, you'll end up with a number. Take that number and multiply it by the MOA/mil number you got when ranging. Example: You have a 6x-24x scope that is set to range at 14x from the factory, and you want to range on 24x, here's what ya do: Range as you normally would. Take the mil reading and divide it by 1.71. Then factor the new mil reading into the standard formula. 1.71 is obtained by dividing 24x by 14x: 24 / 14 = 1.71. You divide the power you want to range with by the pre-set ranging power. You can use this method for any power on your scope, i.e., if you want to range on 20x: 20 / 14 = 1.43 So, you have a known target size of 20". You range and get a reading of 2.225 mils. Your formula when ranging at 14x would be: (Size target in inches X 27.778) / mils = distance in yards (20 x 27.778) / 2.225 = 250 yards If you were ranging at 24x, take your mil reading of 2.225 and divide by 1.71: 2.225 / 1.71 = 1.3 is your new mil reading. The formula would be: (20 x 27.778) / 1.3 = 427yds Easy thing to do is to go ahead and figure out the adjustments ahead of time and write'em down. |
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Quoted:
With an FFP scope you can readily range at any power, as the size of the target changes at the same rate as the reticle when adjusting the power. This is not true if the SFP scope; the reticle remains the same size regardless of the magnification. On the SFP, if you take the power you want to range with, and divide it by the power you're supposed to range with, you'll end up with a number. Take that number and multiply it by the MOA/mil number you got when ranging. Example: You have a 6x-24x scope that is set to range at 14x from the factory, and you want to range on 24x, here's what ya do: Range as you normally would. Take the mil reading and divide it by 1.71. Then factor the new mil reading into the standard formula. 1.71 is obtained by dividing 24x by 14x: 24 / 14 = 1.71. You divide the power you want to range with by the pre-set ranging power. You can use this method for any power on your scope, i.e., if you want to range on 20x: 20 / 14 = 1.43 So, you have a known target size of 20". You range and get a reading of 2.225 mils. Your formula when ranging at 14x would be: (Size target in inches X 27.778) / mils = distance in yards (20 x 27.778) / 2.225 = 250 yards If you were ranging at 24x, take your mil reading of 2.225 and divide by 1.71: 2.225 / 1.71 = 1.3 is your new mil reading. The formula would be: (20 x 27.778) / 1.3 = 427yds Easy thing to do is to go ahead and figure out the adjustments ahead of time and write'em down. Dude even as a Marine myself, I just need to get a class on this, because "math for Marines" and all. 
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| From looking at the ffp reticles, it just seems that they are so small at lower powers that it would be impossible to measure anything. Perhaps it's just me. When you are using a ffp scope do you still tend to use the highest mag for ranging to increase you precision on the measurement? |
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Quoted:
From looking at the ffp reticles, it just seems that they are so small at lower powers that it would be impossible to measure anything. Perhaps it's just me. When you are using a ffp scope do you still tend to use the highest mag for ranging to increase you precision on the measurement? I agree with you on this. I had a Vortex 2.5-10x32 FFP and from what I saw, it was only worth ranging from say 6x and up. It was hard to see the has marks at low power, and the accuracy of the ranging would suffer compared to ranging on the higher power. On 2.5x, the reticle was more or less an aiming point and it would be all but impossible to accurately range with, at least knowing that you could turn it up a little and get a better measurement. Also, IMO, if you've zoomed down to lower power, it's more for FOV on a moving target, so ranging isn't something you're gonna have time to pull off if your target is moving (movers on a range maybe, but it's not like a living target it going to wait for your calculations). I sold the Vortex and stuck with my SFP 2.5-10 Nikon. I see similar in the 1-4 and 1-6x scopes. At least there, the reticle is often functional like a red dot on 1x. |
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Quoted:
Another thing to consider besides just the concept of ranging, are holds for both windage and elevation. I tend to hold for wind rather than dial. When shooting at less than full magnification, my holds on a FFP optic remain consistent. Yep. Folks think about ranging and don't consider hold-offs and moving target leads. For a scope with a top end of 10x or less, I prefer SFP. |
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As mentioned the ability to hold for wind or elevation when not at mid or max magnification is very nice. Having flexibility to work your magnification adjustment to get a balance of FOV and detail is nice. I tend to work between 12-20x a lot and the FFP reticle will allow fast holds.
That being said SFP is nice for super high magnification to get thin reticles and at lower mags where closer distances don't require the detailed reticles. |