Rifle Scopes Subtenison width question

[ronas]

Both scopes are FFP and will be used on TRG-22 for shooting to 800 yards for now and then 1000 yards when we move to new range. I will mostly be shooting paper targets for small group size.

If subtention in crosshair of scope A is .06 mils and scope B is .025 mils. will the fact that the subtention of scope A which is just barely over 2x as wide as scope B end up covering up much of the x ring to any significant degree when scope is used at 25x. I have never used a FFP scope before. Scopes are both 5-25x56.

 

[gstaylorg]

Re: Subtenison width question

At the distances you listed, crosshairs of the stated dimensions will subtend the following arc lengths (in inches):

<span style="text-decoration: underline">800 yd</span>

0.060 mil - 1.728"

0.025 mil - 0.720"

<span style="text-decoration: underline">
1000 yd</span>

0.060 mil - 2.160"

0.025 mil - 0.900"

I didn't round any of these numbers off, but for your purposes, I'd imagine one tenth of an inch would be more than close enough. If you're interested, the calculation to determine these arc lengths is as follows:

<span style="font-weight: bold">(line thickness in mil) x (3.6"/100 yd) x (actual distance in yards)</span>
where 3.6" is the arc length in inches subtended by an angle of one milliradian at 100 yd.

You didn't mention what type of targets you'd be using, or how wide the x-ring would be, but this will hopefully give you some idea of how much of your intended target will be occluded by the reticle crosshair.

 

[ronas]

Re: Subtenison width question

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You didn't mention what type of targets you'd be using, or how wide the x-ring would be,</div></div>

F class targets with 5" x ring.

THank you for formula.

 

[bm11]

Re: Subtenison width question

Schmidt and Bender's p4f reticle is .035 mil thick, as are some of their new offerings. Their 5-25 scopes are excellent, and I only bring this up because it sounds like you are looking at a Premier Heritage 5-25x56 Gen 2 XR and one of the thicker Schmidt reticles.

 

[ronas]

Re: Subtenison width question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">Schmidt and Bender's p4f reticle is .035 mil thick, as are some of their new offerings. Their 5-25 scopes are excellent, and I only bring this up because it sounds like you are looking at a Premier Heritage 5-25x56 Gen 2 XR and one of the thicker Schmidt reticles. </div></div>

I have S&B 5-25x56 on order with the new MOA reticle. However I'm pretty sure the MOA reticle subtensitons that I am making reference to are .03 mil. The same scope with the P4 fine reticle has the same subtenstions of .035 mil.

I have considered Premier due to long delivery time for S&B.
The 5-25x56 Premier with GEM 2 XR reticle has crosshair subtentions of .025 mil and the MOA-ER reticle has subtions of
.058 mil, over twice as thick so much more of X ring will be covered by reticle.

I believe my computations are correct, but if I'm wrong please feel free to chime in.

 

[dcjs]

Re: Subtenison width question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ronas</div><div class="ubbcode-body">I have considered Premier due to long delivery time for S&B.
The 5-25x56 Premier with GEM 2 XR reticle has crosshair subtentions of .025 mil and the MOA-ER reticle has subtions of
.058 mil, over twice as thick so much more of X ring will be covered by reticle.

I believe my computations are correct, but if I'm wrong please feel free to chime in. </div></div>

Ronas,

the MOA-ER reticle has a crosshair thickness of 0.1MOA which is ~0.03 mil, so it's barely just thicker than the Gen2XR.