Calculating reticle holdover with AB

[Daveuk]

I though I had my head around this but need some help!

I have a 260 rem firing 140g Hybrids at 2950FPS ...at least that's what my Magnetospeed chrono says!

It has a S&B 12 - 50 x 56 scope which should show true mil subtensions at 25x mag....P4L reticle.

Sight height is 2.0865"

Unfortunately the scope has a mil reticle but MOA turrets....should have thought before buying!

Resolving a 1400 yard shot as an example I get 45.4 MOA total come-up over my 100 yard zero.

If I opt to dial 40MOA then I need to holdover 5.4moa BUT the reticle display in AB is indicating just over 3 mils of holdover.

Am I being stupid? (hope so!) .....5.4 moa is more like 1.5 mils I think?

 

[cdparker]

Take a look at this: http://www.snipercountry.com/articles/mildot_moa.asp
1 mil equals about 3.6" at 100 yds.
HTH

 

[fredo]

MOA--->mrad conversion, divide by 3.438
So, yes 5.4MOA would equate to a ~1.5mil holdover (with your SFP scope's mag ring set on RANGING power)

You can also use a free ballistic calculator like JBM, and simply change the output units. Make a 'dial chart' for the turret, and a 'holdover' chart for your using your reticle...

As an aside, this is why having matching reticle & turrets simplifies things, greatly. And having a FFP scope where the reticle subtends true at any mag. setting makes it even more easy...

Good luck & have fun!

 

[Daveuk]

Thanks for the feedback guys.

I would like to replace the scope with a FFP and matching turrets & Ret but funding is the current obstacle.

I am pretty comfortable with either Mils or MOA in general usage ...my real conundrum is why AB software on an android phone is not returning the correct holdover.