Help Me Understand

Why is it that so many rifle scopes, even very high-end scopes, have their BDC or BDC/rangefinding reticles on the second focal plane, such that the reticles features are only valid at one specific magnification setting?

That seems like a handicap to me.  What are the arguments for or against?

13 thoughts on “Help Me Understand

  1. Alan has it right, for most SFP scopes it is worth the money to get a BDC turret for adjusting elevation than bother with a reticle with a “generic” ballistic solution for for a generic load.

    However, most folks like the “oooh shiny” factor rather than any sort of functionality. On some of the better scopes we are seeing mil/mil or moa/moa FFP offerings for people those who like to shoot long range. Even Millett is offering those features in the “medium price range” category.

  2. I guess it depends on your definition of high end, but you’re right, if you are using your reticle for holds, leads, range estimation, etc…, it can be confusing to do the math in your head if you’re not on the *one and only* setting that the marks are valid for.

    It’s getting more affordable to find FFP scopes with matching reticle and knob units of measure, e.g. mil reticle/mil knobs (or MOA/MOA if that’s your thing). Probably the best value would be the SWFA SS 3-9. The Weaver Tactical and Bushnell scopes are also reputed to be decent for the money.

  3. Scopes in the $2K range. Some have BDC of various sorts, and I can understand the difference between a “generic” holdover and the more precise system of crank-the-knob (then again, the generic holdover reticles are all equally useful, even if the range indications have to be re-thought for your setup and conditions).

    But that wasn’t the point of my question. Some have just the mil dots or what have you, but they’re only valid at that “one and only” setting as you put it. Forget the BDC issue, the mil features don’t work either unless you’re at “one and only”. I have a hard time believing it’s a mere cost saving measure, so I was curious as to whether there was some other, practical reason for the 2nd plane reticle that would make a user want one. I don’t know how they’re put together. Are their fewer lens elements in a 2nd plane system, making them lighter with better light transmission? I can only guess. And wonder. The manufacturers don’t seem to talk about this at all, and why is that?

    I really like the 4x ACOG on a full length AR HBAR, but I figured a variable would be nice. Well then you get into this first vs. second plane business. Dunno, maybe the fixed 4x ACOG is the way to go, but I’ll want a BAC reticle instead of the black line version in the TA01.

  4. Sorry guys, as Lyle notes, its not all cost. One of the issues with FFP scopes is that the reticle increases with size in relation to the target as magnification increases. So the reticle can actually completely obscure the target at distance.

    For instance, I shoot F Class, the “X” ring is 5″ at 1000 yards. If my reticle is .25 MOA, (which is fairly common, and some are thicker) then it will cover a big piece of my target at that distance. That makes it very difficult to make precise shots at long range.

    There are tradeoffs with every system, that is one. If I had to range every shot based on mildots or hashmarks, and my targets were large game or men, then a FFP makes sense, and many snipers prefer them, but for precision targets at known distances, they create their own issues.

  5. Ayup, there are a few very good reasons for SFP scopes, and a mitigating factor.

    1. At very low magnification, FFP reticles tend to subtend very large amounts of a target

    2. At very high magnification, FFP reticles are often so fine, as to make them nearly invisible

    3. IN GENERAL, unless you are using glass etched reticles, SFP reticles are often more fragile than FFP reticles

    The mitigating factor is that it’s very easy to range in even multiples. It’s a simple calculation in your head; so much so that at even magnifications, you can pretty easily memorize the ranges for common reference points (i.e. a 6 foot man is 300 yards away when he crosses 3 hash at 6x, and 900 yards when he crosses 1 hash). It’s not perfectly accurate, but it’s actually a useful ability to have for rapid estimation.

  6. Well, by definition, the FFP reticle subtends the same at all magnifications, but I do get your point. The etched FFP reticle in my old Springfield Gov. scope seems rather thick at high magnification, and if they made it much thinner it would tend to vanish at low power I suppose. Not that I considered it a problem, but I’ve never thought of it that way before. Thanks.

  7. The reticle size issue is the only advantage of SFP that I can really concede, and now that I’m used to FFP, it almost throws me off to use a SFP scope. For pure target shooting, as in benchrest, where everything has to be *just so* in terms of sight picture and you’re dealing with a static paper target at a known distance, the SFP scope is a better choice.

    Chris, on point 2 you have it backwards. They get thin at low magnification (the reticle shrinks with the image). Your point is valid though, in that the subtensions aren’t very usable (if at all) at the lowest magnification. Low magnification is not where you’d be ranging a target, and it’s hard to imagine a scenario in which one would need to hold for elevation or wind without turning the magnification ring first. I equate low magnification with a sudden engagement at relatively close range, which I think would likely be within the point blank range for the rifle’s trajectory. It’s possible you might want to lead a moving target at close range, but there is a lot more leeway at close range (a mil at 50 yards is 1.8″).

    I do have an SFP duplex that I learned to use for holds, but the capability is extremely limited in comparison to a mil FFP scope. What really is limiting about doing it that way is that the subtensions get bigger at lower magnifications. At 10X, the drop from the crosshairs to the heavy bar coincides with appproximately 360 yards. I have to dial the magnification down to get it farther. Dialed all the way down to 3.5X, the lower thin/heavy duplex intersection is about 545 yards with my current load. Beyond that, I’m guessing, and my bullet isn’t going subsonic until after 1100 yards. With a lot of the mil scopes, I could use accurate holdovers all the way out there, and with an FFP scope I could do it regardless of the magnification setting (although, as you point out, the lower setting would be difficult).

    I think the reason that SFP scopes have dominated, and still do, is demand. FFP scopes have been around in Europe for a while. They like them there. Hunters here don’t generally bother learning holds for trajectory, movers, or wind. They guess on the hold and hope they hit the animal.

    FFP scopes are a little trickier to get right, but I think most of the higher costs have to do with R&D and tooling up to make them. They have been trickling down a lot lately in the realm of “tactical” scopes. I’m guessing that the reason you’re not seeing them is that you’re looking at hunting scopes. You can get a decent FFP tactical scope for $400-$500.

  8. I forgot to add that FFP removes something to think about when you’re trying to get a shot off in a hurry: “What magnification am I at?” When you have so many other things to consider: distance, wind, how much to dial/hold, how much to lead, it is nice not to have to add in the magnification setting, then doing the math to convert the value of the the reticle for your current setting.

    I know I have very limited skills in the *thinking* department, but the less variables I have to consider, the happier I am (especially when I’m in a hurry/under stress).

  9. I was looking at the Nightforce NXS 2.5-10X32, which I would consider as a “tactical” scope for an AR rifle, but it’s SFC.

    I totally agree in that I don’t want to have to think that much with regard to my zoom setting. Sort of like having to convert Celsius to Fahrenheit before you can do anything while your house is on fire. I don’t know. I’m starting to think a good fixed power optic is the way to go anyway.

  10. Nightforce has been a little slow to keep up with their FFP line, although they make a great product. The F1 is reputedly superb, albeit spendy. I hear at SHOT that they indroduced more FFP stuff (I think a 5-25).

    I would take a serious look at the SWFA 3-9×42. Maybe it’s too big for what you’re looking for, but the magnification range is close to the Nightforce you mentioned. For AR’s, I’ve been wanting the 1-4×24. I tend to favor a lower low end in a variable, but that’s just my preference. I have no affiliation with the aforementioned company, and I don’t sell scopes. They are real sleepers in the scope business.

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