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Magnification and Subtension

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:34
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Optics GrassHopper
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Hi Everyone,

1st of all, I am very sorry for the stupid question I am about to ask.

2nd My question. Since the reticle size changes base on the magnification of the first focal plane scopes, does magnification and subtension matters at all

Example:
SWFA SS 3-15x42 FFP scope zero at 100 yard, target at 300 yards, scope zoom in at 10x. Does that means my actual subtension of 1 MRAD reticle space are now 2 MRADS?

OR

Reticle Space are still 1 MRAD?  



Thank You
JC


 

 
 











2
a 26"
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:39
Son of Ed View Drop Down
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" This is a serious question for the College graduates...You lost Eduardo when you said 'subtension' and 'Mil-Rad'.... "   








Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:39
billyburl2 View Drop Down
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On a FFP scope the sub tensions of the reticle will always be the same, regardless of what magnification is set on. If it is 1mil at 3x, it will be 1mil at 15x, and everywhere in between! 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:40
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:41
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I was under the impression that it depended if the reticle was on the first or second focal plane. 

I believe if it is on the first focal plane then the distance between marks is always constant, i.e. 1 mil will always be 1 mil.

But if it's on the second focal plane, then there is 1 set variable used for sighting/distancing. I have found that for most scopes using SFP it is the 10x variation.


I'm new to these kind of optics so you'd be better off waiting for someone else to respond but I hope to possibly provide some insight in the mean time :)
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:59
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Optics GrassHopper
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Thanks Billy

BTW... LOVE YOUR STATEMENT
"If it is tourist season, why can't we shoot them?"
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 19:59
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The scope in question,I.E. a SS 3-15x42 is a FFP scope, hence my answer. It even says it is a FFP scope in the original post...
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/18/2015 at 20:01
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Being from 15 miles south of Sedona Arizona tends to give people a certain attitude...
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/19/2015 at 09:19
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I would say come visit Montana to get away from there for a while, but then you might be a tourist.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/19/2015 at 18:18
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Originally posted by helo18 helo18 wrote:

I would say come visit Montana to get away from there for a while, but then you might be a tourist.
 Its cold enough down here in Colorado! I have been here a couple of months now and have yet to have a week when it hasn't snowed...Whacko
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: May/19/2015 at 18:50
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Which makes it convenient for reliably consistent 2nd FP scopes.  With a 6-24, "adjusted" to 12x for mil ranging, subtensions are 1/2 at 24x and double at 6x.  


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