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rcs9250 · April 17, 2012, 07:29 PM

I have a Leupold MK4 6.5x20 M5 scope with the TMR reticle.

I am a little confused about something. The scope is of course first focal plane, which me. ans that ranging via use of the mil marks can be done at any power.
That of course makes it easy to not make mistakes when ranging a target
and not remembering to have it on the correct magnification.

The part that I am confused about is in the manual. On the page in the manual that shows all the mil size break down for ranging ( target size verifying) it has a a list of sizes at certain yardage for the verticle and horizontal stadias. It states that the wires will be a specific width at certain powers which can be useful in target ranging. In otherwords, it helps break down the measurement into smaller units to be more accurate.
It also has a similar yardage chart for the center square aperture in the very center of the scope where the stadia wires almost intersect. I say they almost intersect because they stop short of center leaving a clear square. Pretty small but it's clear. That aperture size is a different dimension for differing yardages.
What I don't understand is , if it's a first focal plane, why do the other mil marks remain the same but the stadias and square aperture change depending on the magnification level ?
If someone knows and responds keep it in plain english if you could. Not being an engineer it might help to keep it in every day terms or example.

Thanks,
Randy

April 17, 2012, 07:29 PM	#1
rcs9250 Junior Member Join Date: April 17, 2012 Posts: 2	Leupold TMR Reticle I have a Leupold MK4 6.5x20 M5 scope with the TMR reticle. I am a little confused about something. The scope is of course first focal plane, which me. ans that ranging via use of the mil marks can be done at any power. That of course makes it easy to not make mistakes when ranging a target and not remembering to have it on the correct magnification. The part that I am confused about is in the manual. On the page in the manual that shows all the mil size break down for ranging ( target size verifying) it has a a list of sizes at certain yardage for the verticle and horizontal stadias. It states that the wires will be a specific width at certain powers which can be useful in target ranging. In otherwords, it helps break down the measurement into smaller units to be more accurate. It also has a similar yardage chart for the center square aperture in the very center of the scope where the stadia wires almost intersect. I say they almost intersect because they stop short of center leaving a clear square. Pretty small but it's clear. That aperture size is a different dimension for differing yardages. What I don't understand is , if it's a first focal plane, why do the other mil marks remain the same but the stadias and square aperture change depending on the magnification level ? If someone knows and responds keep it in plain english if you could. Not being an engineer it might help to keep it in every day terms or example. Thanks, Randy