FFP vs SFP after ranging

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BeagleBoy360

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I am looking at getting a new scope, and I am trying to determine if i get a FFP or SFP scope. I understand about ranging items is much easier with a FFP.
But I am trying to understand, if you range an item on a SFP scope, (at max power) and the hold over is 2mil, if you back off the power a bit.
Will the hold over still be 2 mil, or will you have to change the calculation for the magnification you change to.

Also, 2nd topic, what do you guys like better, MOA or MIL, I understand the math behind both, but for range shooting alone ( don't plan to be hunting ) what do you like better.
I want to get into long range +700 when I can find places to shoot. So I am wondering what math do you find easier in your head without paper and pen.

Thanks for your input.
 
1) on a SFP, the retical is only true at one magnification, usually 10x or max.. as you zoom in and out , the retical/target ratio changes, so lets say your have a mildot retical in your scope and your scope ranges properly at 20x, range your target, and you back down to 13x, you are WAY off as you would be some where around .65 mills per hash mark in your retical.. does that make sense?? so now that 2mil hold would be just a c-hair over holding 3mils

mil/moa are both angular messurements.. just make sure your turrets match your retical... and then its just personal preferance... adjustments on MOA scopes (1/4 moa) is finer then .1 mil adjustment
 
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Well the next thing I want to know is with FFP when the reticle grows with the magnification, would it be a issue with a Vortex Viper PST.

I am trying to decide between the Vortex Viper PST 6-24x and 4-16x. in MOA and MIL
 
Sorry for the hijack but. I want to know how thick a c-hair is and did ultimate monkey measure a bunch of different one to get a standard thickness?
 
I just recently bought a PST 6-24x50. Love the scope so far. I had the same quandary and ultimately went with SFP, EBR-1 in MRAD. I personally didn't like how small the subtensions got when at lower magnifications. Very hard to read.

Ranging is done at 24x, but understanding the calculations at the pre-set lower magnifications is not hard either. I chose MRAD just because. Always used MOA and wanted something different.

From the Manual:

In the Viper PST second focal plane riflescopes, the listed MRAD
subtensions of the EBR-1 reticle are only valid at the highest
magnifications of the scope. However, by understanding the
relationship of magnification and subtensions, you can still calculate
ranging, holdovers, and wind drift at partial magnifications. Here are
some examples:
• If the magnification is set at 1/2 the full magnification, subtension
values will be two times the spec listed in the manual.
• If the magnification is set at 1/3 the full magnification, subtension
values will be three times the spec listed in the manual.
• If the magnification is set at 1/4 the full magnification, subtension
values will be four times the spec listed in the manual
Click to expand...


http://www.vortexoptics.com/uploads/web_manual_ret_viper-pst-6-24x50-sfp_r624s1-m-12a.pdf
 
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Correct me if I'm wrong, but it's ranging done at 18x on the 6-24 model?

This is from the HS-T (MOA) manual, but I wonder if it applies to other Vortex models.

Second Focal Plane reTicleS
Second focal plane (SFP) reticles are located near the scope’s eyepiece
behind the image erecting and magnifying lenses. This style of reticle
does not visually change in size when you change the magnification.
The advantage of an SFP reticle is that it always maintains the same
ideally-sized appearance. When shooting with this SFP scope, be aware
that the listed reticle subtensions used for estimating range, holdover,
and wind drift correction are accurate at the highest magnification
for all models except the 6-24x50. For 6-24x50 models, the reticle
subtensions are accurate at 18x.
Click to expand...
http://www.vortexoptics.com/uploads/web_manual_reticle_vhs-vmr-1-moa-13b.pdf
 
awndray said:
Correct me if I'm wrong, but it's ranging done at 18x on the 6-24 model?

This is from the HS-T (MOA) manual, but I wonder if it applies to other Vortex models.


http://www.vortexoptics.com/uploads/web_manual_reticle_vhs-vmr-1-moa-13b.pdf
Click to expand...

On the PST, 6-24 it is at full magnification. Check the PDF link I posted. Page 5.


http://www.vortexoptics.com/uploads/web_manual_ret_viper-pst-6-24x50-sfp_r624s1-m-12a.pdf

Subtension Changes with Magnification
6–24x50 Reticle Subtensions
(Valid at 24x)

RIFLESCOPE MAGNIFICATION ACTUAL SUBTENSION OF 1 MRAD RETICLE SPACE

24x 1 mrad
12x 2 mrad
8x 3 mrad
. 4 mrad
Click to expand...

The same scope in MOA slightly different.

http://www.vortexoptics.com/uploads/web_manual_ret_viper-pst-6-24x50-sfp_r624s1-a-12a.pdf
 
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Right-on. I've been going back and forth, trying to make up my mind on which model I want. This might help, or confuse me further.
 
awndray said:
Right-on. I've been going back and forth, trying to make up my mind on which model I want. This might help, or confuse me further.
Click to expand...

I was not overly concerned with getting the SFP just because I went with the 24x to use it. I shoot mainly at the range, on a bench, so it is always on 24x. I don't for see doing a lot of ranging.
 
this stuff really flips my switches. Ill explain why:

Firstly: if you use the reticule for wind holds you have to use your ranging magnification. This is critical being anywhere at anytime including a gun range. its asinine to be in the middle of a group at the wrong magnification when you notice you have some wind rolling in. then you're just all messed up and you don't know where to shoot.

Secondly: Variable power scopes serve a purpose, that being you can dial in or out of your magnification for better optical clarity. whatever magnification you need is where you are working. the thought that you have to dial in or out to do a task is just another step that you do not need. ever.

if you are only going to shoot at the range, get a fixed power scope up to that x50 zoom you want. I am totally cool with that.

lastly, it grinds my gears that people will invest in these inferior 2fp scopes, only perpetuating the cycle of having these junky scopes on the market when you're done with them. Scope companies should be mastering their craft from the input from the customers. They can do this by producing less ####ty scopes and devoting their time and efforts to quality products. Oh but they need to reduce costs? fixed power scopes. bam. cheaper to make then viable. and you get exactly what you want.

i dont know how else to explain this so ill leave it at that.

thanks for reading my rant.
 
Sorry, there is nothing inferior in a 2FP scope. You don't like them fine. I did LOTS of research when deciding what to buy because I do not drop money easily. SFP works great for range shooting.
 
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