mil dots for hold over

[1chota]

any one got a method for using the mil dots for hold over for .223 and .308? what zero?

1chota

[n2ipsc]

Pretty broad topic, and your choice of zero is equipment-, load-, deployment-, and personal-dependent, but...

Just remember that 1 mil is, for general purposes, 3.5 MOA (conversely, 1 MOA is about 1/4 MR), and determining holdovers should be easy (the actual numbers are 1 MR = 3.44 MOA / 0.29 MR = 1 MOA).

Consider (strongly) buying a MilDot Master to go with your kit...tremendously helpful... And play around with some ballistic calculators (like THIS ONE)...

[More detail than you wanted to know, most likely, but...]

Milliradians-to-MOA Conversion...

1 circumference = 6.2832 radians = 360 degrees

So... 6283.2 MR = 21,600 MOA

or... 1 MR = 3.4377 MOA

and... 0.2909 MR = 1 MOA

and... 1 MOA = 1.0472 in @ 100 yds

and... 1 MR = 3.6000 in @ 100 yds

If we say that…

1 MR ≈ 3.5 MOA

3.5 MOA = 3.6652 in @ 100 yds

1 MR = 3.6000 in @ 100 yds

or 0.0652 in @ 100 yds error

or 0.3260 in @ 500 yds error

0.25 MR ≈ 1 MOA

0.25 MR = 0.9000 in @ 100 yds

1 MOA = 1.0472 in @ 100 yds

or 0.1472 in @ 100 yds error

or 0.7360 in @ 500 yds error

Edited May 23, 2009 by n2ipsc

[dogdoc]

Wow, that made my head hurt

For the set-up I use, which is a NF 2.5X10 mil-dot, on an 18" Larue, I zero the rifle at 200yds, and the first mil-dot is on at 300yds, second at 400yds and so on... This is with heavy bullets, 69 or 77gr. Now I'm not saying this is precision rifle accuracy, but it is accurate enough to hit 10-12" plates at 400yds, with speed while on the clock, without any problems! I've personally tested this out to 700yds on a steel IPSC target, and at that point your using where the crosshair meets the post as your holdover. I've used the same holdovers with a NF 1-4.

I'm not sure how well this would work with other mil-dots, i.e. Leupolds are oblong. Theoretically it shouldn't matter.

Disclaimer: Your results may vary, but I've had good success with this.

Edited May 23, 2009 by dogdoc

[lefty556]

Depending on the load, my results are on par with DogDoc. I'm running a 68 grain Hornady HPBT at just over 2800 fps. Zero at 100 yds. Disregard drop at 200 (it's only about 1.5 MOA). At 300, I use the bottom of the first dot. At 400, I'm holding 2-2.25 Mils high. 500 yards is about 3.5 Mils. That's with a NightForce NXS 1-4.

[Toolguy]

Pride-Fowler at www.rapidreticle.com makes scopes just for this.