Embarrassing optics question

[Bushwack44]

If you have two manufacturers (i.e. Nikon & Vortex) that both offer 4-12x40 scopes, would the BDC reticle estimates be the same for both at 200, 300, 400+ yards? Or..is it the crosshairs distance in each scope (in part) that determine estimate drop (using the software)?

I ask as I'm wondering if a person can (somewhat accurately) use Nikon's Spot-On app with a Vortex, Redfield or similar scope having the same Nikon magnification? Anyone try this with some success?

[ke6guj]

its hard to say. each company's BDC may be calibrated for a different weight bullet at a different velocity.


here are two examples,
Primary Arms


Burris


both are BDCs for .223, but how much do they match?

[Mute]

BDC reticles are calibrated for specific loads and environmental conditions. You need to find out what those are for each of the different scopes. They may or may not coincide.

[Bushwack44]

Understood, but are they calibrated for different scopes. If I know the environmental conditions & specs for load and input the data in the software, will a Vortex scope's reticle be as accurate as the Nikons?

BDC reticles are calibrated for specific loads and environmental conditions. You need to find out what those are for each of the different scopes. They may or may not coincide.

[ExtremeX]

Understood, but are they calibrated for different scopes. If I know the environmental conditions & specs for load and input the data in the software, will a Vortex scope's reticle be as accurate as the Nikons?

Its not a complicated question... just look at the website and look at the reticle subtensions. Vortex does a great job of publishing that data on their site...

For example:
Subtension detail for the Diamondback 4-12x40 Dead-Hold BDC Reticle MOA.

http://www.vortexoptics.com/uploads/sub_dbk_s_4-12x40_bdc_moa-t.jpg

You can compare that to any load you shoot to see where it would be... Even if a 400 yard marker (in this case, 7.5 MOA) was good for one load, it might just mean that's a 515 yard marker for a different load... it really doesn't matter as long as you know what that measurement is in MOA or MRAD. That said, I just like working with standard mil scale or moa scaled reticles so I don't have to remember non-standard graduations.

[Mute]

Understood, but are they calibrated for different scopes. If I know the environmental conditions & specs for load and input the data in the software, will a Vortex scope's reticle be as accurate as the Nikons?

The subtensions are constant. As long as they are physically accurate, then they will work within their designated parameters. Now some variation in any of these factors may alter the point of impact a little or a lot, but for the most part they'll be fine if the conditions don't stray too far from what the reticles were designed for. Most of these BDCs are close enough for government work, but I wouldn't trust using the BDC for shooting tiny little groups. I'd use the dials for that. I would trust the reticle IF I can coincide them with some kind of angular measurement (MOA or Mil) consistently.

I don't think you're going to find the BDC solutions from one manufacturer any more or any less accurate than from another one.

[JMP]

Its not a complicated question... just look at the website and look at the reticle subtensions.

Most people that see the simplicity generally don't get the BDC reticles.

[ExtremeX]

The subtensions are constant. As long as they are physically accurate, then they will work within their designated parameters. Now some variation in any of these factors may alter the point of impact a little or a lot, but for the most part they'll be fine if the conditions don't stray too far from what the reticles were designed for. Most of these BDCs are close enough for government work, but I wouldn't trust using the BDC for shooting tiny little groups. I'd use the dials for that. I would trust the reticle IF I can coincide them with some kind of angular measurement (MOA or Mil) consistently.

I don't think you're going to find the BDC solutions from one manufacturer any more or any less accurate than from another one.

I think its safe to assume the OP is looking at SFP scopes, and if that's true, then the subtensions are NOT constant.

It will change as magnification changes, unless its used only at the one magnification its designed for, generally MAX.

That's a lot of data to keep track of even with the assistance of software like Spot-On which I personally cant stand...

Also +1 and I agree with the 2nd part... I have never owned a BDC that actually matched up perfectly to the ammo I was shooting, even if it was "designed" for that load. Too many other variables to take into account. I much prefer to build my own range cards using a normal scope.

[Bushwack44]

Thanks everyone for the input. Questions answered and learned a li'l something.

[ifilef]

Most people that see the simplicity generally don't get the BDC reticles.

JMP- Mind elaborating as to exactly what was meant re the above statement?

[ExtremeX]

JMP- Mind elaborating as to exactly what was meant re the above statement?

I think the point he was trying to make was that if you know how to use a rifle scope and even a basic understanding of ballistics, BDC scopes actually become the more complicated solution as it doesn't adapt well to changes in ammo/load or other variables.

The simplicity comes from understanding the system and being able to answer "the question" yourself vs relying on someone else for what MIGHT be the right answer.

[big blaze]

This is why I don't like BDC reticles.

[RogueSniper]

BDC are calibrated with maximum magnification, right? My problem: I shoot 6.8SPC and none of the BDC are calibrated for that caliber. For that reason, I keep notes on my loads, distance, and conditions when I'm at the range. I'm relatively accurate when I'm in the field. My target size is about 2"-3" and I'm usually on target. Unless, of course, I ranged the target incorrectly, which is why I bought a rangefinder. I might abandon the BDC reticle and stick to click adjustment.

[Unretarded]

A BDC scope is not the way........

[JMP]

JMP- Mind elaborating as to exactly what was meant re the above statement?

I think the point he was trying to make was that if you know how to use a rifle scope and even a basic understanding of ballistics, BDC scopes actually become the more complicated solution as it doesn't adapt well to changes in ammo/load or other variables.

The simplicity comes from understanding the system and being able to answer "the question" yourself vs relying on someone else for what MIGHT be the right answer.

Yes, that basically sums it up. I think BDC reticles make sense in streamlined optics like the ACOG where you aren't shooting that far, 400-600 yards. Once you go with a full sized scope, the BDC reticles will generally complicate things, and they will virtually never conform to have an exact match with your rifle's ballistics unless you are shooting with a defined ammo and riflespec. Even then, you won't be exact since the environmental conditions change your drops as well.

If you want a good reticle that you can hold over, then you may want to look at the Xmas tree or Horus-like reticles. The key is knowing how your rifle shoots. I think that folks that shoot multiple long range cartridges tend to see the BDC in a negative light. If you are just shooting a couple of more common rifle cartridges like the .223 and .308, then it may make some sense.