Need some math help.

[ferntree]

I have a long range reticle on my Leupold 2-7. It has two dots below the crosshair for long range shots. I have the data of how far the dots are:

200 yd zero
at 7 power
first hold over dot 2.2 MOA drop is 285 yards
second hold over dot 4.8 MOA drop is 367 yards
bottom duplex hold over 7.8 MOA drop is 450 yards

at 2 power
first hold over dot 5.77 MOA drop is 395 yards
second hold over dot 12.66 MOA drop is 560 yards
bottom duplex hold over 20.62 MOA drop is 715 yards

I want to get the first hold over dot to be at either 250 or 300. Leopold says its designed for a 200yd zero with 300, 400 hold over dots and 500 at bottom duplex.

The way you adjust this is by dialing on the power ring. As you can see by the data it will be closer to 7 power than 2 power obviously. But like all this stuff, I m sure there is a way to do the math to find out so I don't have to waste the ammo.

I was gonna mock it on a paper target where zero is and where 300 yards would hit and match the impact dot on the paper with the hold over on the reticle but I can't imagine being able to see the dot at 200 yards.

Anyone with some ballistic/(math) knowledge that can help about would be greatly appreciated.

page 2 left side has the info.

http://leupold.com/wp-content/uploads/2015/03/2015-reticle-information.pdf

[emarkham]

since this has sat around for a couple of days without anyone responding, I'll take a stab at helping out.

I looked at the Leupold PDF you linked, I can't see where there's any mention of which caliber/cartridge those BDC reticles are calibrated for. And you don't mention what load you're shooting and at what velocity.

so, in absence of either it's a wild-*** guess as to what the BDC is supposed to show for you, but Whatever you are actually shooting has a better BC or higher velocity (or both) than what the reticle was designed for

you can find out what the correct load is supposed to be, or you can learn to live with what you have. your choice.

[AreWeFree]

Easiest way is to use an online ballistic calculator to generate a drop table that you can correlate to your reticle.

Here's a simple ballistic calculator: http://www.hornady.com/ballistics-re...ics-calculator

[ferntree]

i think leupold is pulling a bs marketing gimmick. i know you can't have a BDC reticle without expressing exactly which load you are using. I did the math and found with the hog hammer 168gr the zero is at 200 and the first dot is 298 at 6.375 power. the second dot is around 92 and the top of the stadia is around 486.

basically this is all for nothing as i was looking at the description and its actually 6.7 at max power, not 7. so all my math and numbers are off. also my reticle fades in and out. anyone have that happen to them? i think it is actually moving in the scope . . .

[AreWeFree]

i think leupold is pulling a bs marketing gimmick. i know you can't have a BDC reticle without expressing exactly which load you are using. I did the math and found with the hog hammer 168gr the zero is at 200 and the first dot is 298 at 6.375 power. the second dot is around 92 and the top of the stadia is around 486.

basically this is all for nothing as i was looking at the description and its actually 6.7 at max power, not 7. so all my math and numbers are off. also my reticle fades in and out. anyone have that happen to them? i think it is actually moving in the scope . . .

Yes and no. From the document you linked you don't have a BDC, rather a "ballistic reticle."

In any case, you can make this work since they list the subtensions, you need to create a drop table of your actual load and apply it to your reticle.

e.g., if you range something to X yards and need 3.8moa drop you would hold over 2/3 down between the first and second dot (thereabouts anyway.)

[SonofWWIIDI]

I got nothing, but I'm interested to follow along and read the results.



Good luck.