How to Calculate Reticle Substension with Magnification Change

[Lone Hunter]

Could someone please help me in a way to figure my reticle substensions when I change magnification on my scope??
My scope is a NF 12x42x56BR. It has 40 MOA total elevation. Reticle is NP1-RR. Scope has dots at 4moa,8 moa, 15 MOA, and 20 MOA. The ranging shows correct for 22x on the scope . My question is how can I figure out (besides shooting it) where the dots would be on say 32x or 42x?? . After a 100 yd zero I have 26.4 MOA left in the scope. Enough to shoot 600yds but not 1000 yds. What I was going to do was use the dots as holdovers but want to increase my magnification past 22x. Attached is a picture of the reticle.
Any and All help would be greatly appreciated.

 

[dstoenner]

It is just a simple ratio of the reference magnification divided by the in use magnification times the reticle value. So for example you are using a magnification of 32 and you want to see about the 10 moa dot. It is (22/32)*10= 6.875 moa

HTH

David

 

[Lone Hunter]

It is just a simple ratio of the reference magnification divided by the in use magnification times the reticle value. So for example you are using a magnification of 32 and you want to see about the 10 moa dot. It is (22/32)*10= 6.875 moa

HTH

David

David,Thank You For the reply. My holdovers or dots are substended at 4,8,15,20 MOA. By your reply all I would have to do for each dot is your formula and that will give me the holdover MOA for the substensions? If I wanted to turn magnification up to 42x then I would use your formula like (22/42)*20=10.48 MOA. That means at 42x the 20 MOA dot Substension would be 10.48 MOA? I hope this is correct!! If so, it is a lot simpler than I thought. If not, what would the 20 MOA dot be? Thank You, Greg

 

[Johnny_V]

Strelok Pro does the calculation for you in his app. After inputting yardage, hit "reticle " and your reticle shows the distance at whatever power is dialed in, and this can be done on the fly.

 

[dstoenner]

David,Thank You For the reply. My holdovers or dots are substended at 4,8,15,20 MOA. By your reply all I would have to do for each dot is your formula and that will give me the holdover MOA for the substensions? If I wanted to turn magnification up to 42x then I would use your formula like (22/42)*20=10.48 MOA. That means at 42x the 20 MOA dot Substension would be 10.48 MOA? I hope this is correct!! If so, it is a lot simpler than I thought. If not, what would the 20 MOA dot be? Thank You, Greg

You are correct and you are welcome

David

 

[Lone Hunter]

Strelok Pro does the calculation for you in his app. After inputting yardage, hit "reticle " and your reticle shows the distance at whatever power is dialed in, and this can be done on the fly.

View attachment 1100385

John, I have Strelok Pro and like it. The problem is as most scopes are calibrated at one magnification. My 5.5x22 and 12x42 are both calibrated at 22 power. That's where Strelok calibrates at 22x. That was why I was asking about different magnifications. MOA Dot is different at different magnifications. Look at Strelok and see but I believe they only go to the ranging power which is 22x. I like also how you can dial it in with he turret on top top. Thanks, Greg

 

[Lone Hunter]

You are correct and you are welcome

David

David, Thank You Very Much For The Help. I Really Appreciate It. Very simple way to figure things. Greg

 

[Zero333]

No matter what the calculation, you still should verify with live ammo at 100 yards. Sometimes when the scope is at 30 power it might actually be at a true 27 power.


At 42 power you would multiply the holdover values by 1.9090909090909 = (42/22)

So at 42 power....

4 moa dot = 7.636363636363 moa = ( 4x1.90909090909)

8 moa dot = 15.272727272727 moa " "

15 moa dot = 28.636363636363 moa " "

20 moa dot = 38.181818181818 moa " "
------------------------------------------------------
36 power = 36 /div by 22 = 1.6363636363636

4 moa dot = 4 x 1.63636363636 = 6.5454545454544 moa

etc.................

 

[Rem06]

or get a FFP and clear your cranium up some?

 

[Lone Hunter]

or get a FFP and clear your cranium up some?

Too much money invested to do that. Hell, if it’s easy it wouldn’t be any fun .. LOL

 

[flatlander]

I shot several PRS-style matches a few years ago before deciding life is too short to stress my poor old mind with trying to calculate leads on movers with the added complication of figuring what the reticle hashes were worth at the reduced magnification I dialed back to for the mover stages. Also lost track of my 100yd zero a few times while shooting with 2nd fp scopes w/o a zero stop...screw it, I finally broke down & invested in a good quality mil/mil ffp scope with a zero stop. Never looked back after that, and now have far more ffp mil scopes than sfp moa ones, and will never go back.

 

[SSL]

John, I have Strelok Pro and like it. The problem is as most scopes are calibrated at one magnification. My 5.5x22 and 12x42 are both calibrated at 22 power. That's where Strelok calibrates at 22x. That was why I was asking about different magnifications. MOA Dot is different at different magnifications. Look at Strelok and see but I believe they only go to the ranging power which is 22x. I like also how you can dial it in with he turret on top top. Thanks, Greg

Unless I am not understanding your question, Strelok Pro has you enter the magnification range of your scope (12-42) as well as the calibration power (22) being set during initial setup by choosing the brand and reticle from the chart. Once you look at the reticle page, the sliding bar changes the magnification and displays the differing yardages (calibrated to each power setting) represented by the various dots in relation to your preselected zero distance.

 

[Lone Hunter]

SSL, Strelok Pro does that with the 5.5x22 but it does not show my reticle in the 12x42. It shows other reticles but not mine. The reticle I have is the NP-1RR. I like the hold over points on this reticle and it ranges pretty accurate fast. 12x42 is calibrated at 22x the same as the 5.5x22. When you change power that will change dot substension. That was what I was concerned about. I wish Strelok would do that for the 12x42. It is a handy feature and I really like it on the 5.5x22.
Just went back and looked and Strelok Pro list other reticles but it appears that they are set at 22x for their calibration also. They do not go above 22x with the sliding magnification but it would be nice if they did.

 

[SSL]

SSL, Strelok Pro does that with the 5.5x22 but it does not show my reticle in the 12x42. It shows other reticles but not mine. The reticle I have is the NP-1RR. I like the hold over points on this reticle and it ranges pretty accurate fast. 12x42 is calibrated at 22x the same as the 5.5x22. When you change power that will change dot substension. That was what I was concerned about. I wish Strelok would do that for the 12x42. It is a handy feature and I really like it on the 5.5x22.
Just went back and looked and Strelok Pro list other reticles but it appears that they are set at 22x for their calibration also. They do not go above 22x with the sliding magnification but it would be nice if they did.

Got it. Try emailing Igor with specs. He is great about updating reticles. You might also try changing the settings in the setup page where it asks for Minimum magnification, Ranging magnification and Maximum magnification. Try entering the Minimum magnification as 12 and Maximum as 42X. I had to do this with a 6-18 power scope that was only listed as 4-16. Both reticles are identical and so far the data appears to match up to actual shooting. This may not work for your issue since the discrepancy is greater than on mine, but might be a short-term fix. Good luck.

 

[Ledd Slinger]

@dmoran has some pretty sweet software for generating and calculating all this. Hopefully he'll chime in or you can send him a PM.

 

[Johnny_V]

Would this happen to be your reticle?

 

[Lone Hunter]

No sir, It is the NP-1RR. Older reticle discontinued. Center crosshair is your zero. Next dot down is 4 MOA,next dot 8 MOA, next dot 15 MOA, next dot 20 MOA holdovers. At the top and bottom of the dots are where your vertical lines are its 3 MOA at the bottom of the vertical line 5 MOA at the top of the vertical line below the 4 MOA dot. This goes this way through the Substensions. Say at the dot for 20 MOA the bottom of the vertical line from 15 MOA dot will be 19 MOA and the top vertical below the 20 MOA dot will be 21 MOA. It's a reticle I really like but you have to use it to get used to your holdovers. With them you don't have to dial elevation as much.

 

[Lone Hunter]

The vertical portion of the reticle has a series of dots placed at
specific M.O.A. hold points. These hold points represent 4, 8, 15
and 20 M.O.A. with a 1 M.O.A. spacing around all hold point
dots. Example: The first hold point dot below center aim point
(hold point “B”) represents 4 M.O.A., the tip of the line above
the 4 M.O.A. dot represents a 3 M.O.A. hold point. The tip of
the line below the 4 M.O.A. point represents a 5 M.O.A. hold point. This is consistent throughout the remainder of the NP1-RR reticle.
This might explain better than what I tried to describe. Can draw it out but not very good with the explanations.

 

[_Raining]

You could always get a canted rail or rings to take advantage of some of that unused adjustments in the scope. You would still want some wiggle room to maintain a 100 yard zero, or if you are OK with a 200/300 yard zero you can get a bigger cant (10 MOA should allow you to have a 100 yard zero. Not sure how common 10 is, a lot of manufacturers have 20 MOA rails/rings). How much more adjustment would you need beyond 26 to reach 1000? Is it a requirement to still have a 100 yard zero?

 

[sscoyote]

Another way to put it is that reticle subtension is inversely proportional to magnification.