Focal plane, first and second

This is very new to me, focal planes so I'd like some advice please.
I bought a vortex diamondback 4-12x40 scope with dead hold bdc for my 223. I have sighed it in, chronied my ammo and input the data into strelok app.
It tells me that the second mark down is 187m for that info at full magnification.
My question is, with it being second focal plane the bdc reticle doesn't enlarge so does that mean the range for the bdc marks stay the same on all zooms or does it does it change as you zoom because the target enlarged?

I was looking into buying the strelok+ app to get more options including the ranges at different zooms but from what I have been reading I may not need to.

Sent from my workbench

Easier to watch this video if I tried to explain it guaranteed someone here would tell me I am talking shit so better for the experts to explain :D

http://www.vortexoptics.com/video/fi...nd_focal_plane

Hey Bud

Being second focal plane means the reticule marks only work for the given magnification, as the reticue doesn't change it means the distance between the marks changes with magnification.
I don't find this an issue as when you are shooting at a range that you need to use your holdover marks you will go to full magnification anyway.
A FP scope the reticule changes size with magnification and therefore stays the same size relative to the target, the reticule marks therefore work at all magnifications.

Hope this helps!

Quote:

---

Originally Posted by hunter308

Easier to watch this video if I tried to explain it guaranteed someone here would tell me I am talking shit so better for the experts to explain :D

http://www.vortexoptics.com/video/fi...nd_focal_plane

---

Thanks dude, clears that perfectly.
So the answer is no, the bdc markers are different ranges on different zooms but the reticle stays the same size at all sons so is better for hunting small game art longer ranges because it doesn't become larger and cover the target

Sent from my workbench

Quote:

---

Originally Posted by Spudattack

Hey Bud

Being second focal plane means the reticule marks only work for the given magnification, as the reticue doesn't change it means the distance between the marks changes with magnification.
I don't find this an issue as when you are shooting at a range that you need to use your holdover marks you will go to full magnification anyway.
A FP scope the reticule changes size with magnification and therefore stays the same size relative to the target, the reticule marks therefore work at all magnifications.

Hope this helps!

---

Thanks mate, makes sense for sure.
I'd rather a second focal plane for what I use it for and really it will be at full magnification most of the time anyway so all good

Sent from my workbench