FFP Versus SFP Scopes For Hunting
BY Herschel Smith
2 years ago
Had this scope been a first-focal-plane (FFP) scope, it would not have mattered at what magnification the scope was set, and we likely would have had 300 pounds of meat to haul out. In a FFP optic, as the reticle is etched or marked on a forward lens in the scope, the holdover hash marks below the crosshair would have been the same value, placing a bullet in the same place at 4X as they would have at 12X. However, this was a second-focal-plane scope, which means the reticle was marked or etched on a lens in the rear, closer to where you look into the scope.
Being a SFP scope, the reticle on my 4X-12X Bushnell will always appear the same size as the magnification is adjusted, but changing the magnification does change the hash marks on the reticle in relation to the target. This is where some of you readers may want to start looking through your scope and twisting that magnification ring. In the story above, at 300 yards, the second hashmark represents approximately 10.5 inches (3.5 inches x 300 yards) of drop at 12X magnification. At 4X magnification, that second hashmark just turned into 31.5 inches (12X = 10.5 inches; 12X/4X = 3 times more value; 10.5 inches x 3 = 31.5 inches). This hold at 4X put the bullet 20 inches over the intended point of impact.
With a FFP scope, the reticle will grow and shrink as you adjust the power ring. This does little good on a scope with a standard duplex reticle, as your only holding mark is the crosshair itself, centered at any power. Where FFP is a help is when you have a drop reticle with hashmarks for simple holdover or when you are using a system such as MIL-DOT. If the scope on that rifle had been a FFP scope with MIL-DOT subtensions, the magnification power would not have mattered as the second hashmark would always be a 10.5-inch value at 300 yards.
That’s all well and good, but that reticle sure does appear small on any power for a FFP scope. If you plan on shooting from one ridge to another, a FFP scope is the best bet. If you plan on shooting east of the Mississippi, you’re probably better off with a SFP scope. I’ve had a FFP scope mounted and wished I had a SFP scope.
But YMMV and everyone has his preferences.
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On October 25, 2022 at 10:53 pm, Furminator said:
I have found that the reticle appears so fine at low magnification in a FFP that it becomes difficult to see in low light and against cluttered backgrounds. If you have time to set up for your shot this isn’t an issue since you will most likely dial up anyway. But if you run low power for fast aquisition shots FFP can be counter-productive when you have to look for the reticle.
A SFP Leupold VX-3i 4-14 with CDS is about the ideal western hunting scope with excellent glass, all the magnification a hunter needs, and the ability to dial for range if really necessary while foregoing the needlessly complex reticles typical of many FFP scopes and the added trouble of parallax adjustment.
On October 26, 2022 at 5:45 am, Wes said:
The writer of the article admits at the top that a mistake was made. I’ve not seen a SFP with a BDC, made by a reputable firm, that didn’t have notes or instructions somewhere saying that the intervals specified are applicable at such & such power. This is usually near the top of the range, e.g., 8x on a 3-9x. SFP folks need to find that number & understand it. It’s amazing to me over the years how much meat went into the freezer from the combination of unadorned crosshair and a few drop numbers committed to memory.
On October 26, 2022 at 8:29 am, Randy said:
To bring a little more clarity to the subject, even the BDC on a FFP scope is largely theoretical because it does not magically know (or account for) the actual ammunition and barrel length you are using. Everything must be **validated** at “the range” (SFP or FFP) for the particular barrel length and ammunition combination you are using. Otherwise, you’re swimming in an ocean of theory, and left wondering why you missed the target.
Altitude is also and issue. A particular rifle-ammo-scope combination will not shot the same at 6,000 feet in the mountains as it did at 300 feet above sea level in a corn field.
On October 26, 2022 at 11:07 pm, Georgiaboy61 said:
Re: “The writer of the article admits at the top that a mistake was made. I’ve not seen a SFP with a BDC, made by a reputable firm, that didn’t have notes or instructions somewhere saying that the intervals specified are applicable at such & such power. This is usually near the top of the range, e.g., 8x on a 3-9x.”
That’s quite correct, but there’s even more: One not only has to learn at which magnification his scope’s reticle features are true and correct, but whether those marks actually subtend the claimed intervals.
Most second-focal plane scopes state clearly in their instructions which magnification to dial in for use of the reticle features. Most of the time, it is the highest-power magnification, but not always – so know before you go! Some makers mark their elevation dial to make this magnification obvious in some manner, which is convenient.
Many precision shooters take the time/effort to “test” their reticle against a known distance scale at a known yardage, to verify that their optics will work as advertised. It is simple to prepare at home a cardboard presentation board or other surface onto which has been drawn or printed a precise scale measured in inches or millimeters, one whose marks are visible through the optic. If you want to get really fancy, lay out MIL and MOA scales as well, and remember that “hunter’s moa (1 inch/100 yds.)” isn’t precisely the same as true moa (1.047″ at 100 yards).
From there it is a simple matter of making sure that the distance to the scale is precisely known, i.e., 100 yards or 100 meters, for example, and then getting stable behind the glass and verifying the reticle gradations against the scale of known size.
Oh, and if one is too lazy to do that, Birchwood Casey or someone like that makes a paper target which is over-printed in gradations of inches or moa. This serves much the same function.
I won’t mention any names, but years back I discovered that an optic of mine had the incorrect reticle installed at the factory, by use of the validation method above. It was a high-end maker, too, not an entry level product. It pays to verify these things.
Re: “To bring a little more clarity to the subject, even the BDC on a FFP scope is largely theoretical because it does not magically know (or account for) the actual ammunition and barrel length you are using. Everything must be **validated** at “the range”
Yes, that’s quite true. BDC-based reticles are, by necessity, compromises designed to get the user as-close to the target as possible under as many sets of conditions as possible, given the variables involved.
The manufacturers who take the time and effort to design their BDC reticles properly, and then dope them out extensively under different conditions, such as Primary Arms with their ACSS reticle line – are making good products which perform well in the field. Other companies do not even mention their reticle designs or how to use them, in their product literature. Yes, that’s right – as hard as it is to believe in this day and age. Judging from my time working in the retail FA and accessories industry, you really do run the whole spectrum from very good to very bad and everything in between. Caveat Emptor.
By the way, if you really want to make that “special shot,” learn about the tall-target test and how to do it. The “box test” performs somewhat of the same functional testing, but not across as significant a portion of the range of adjustment of the scope.
In brief, the problem is this: How do you know that when you dial in 10 1/2 moa of elevation correction on the elevation knob of that fancy new scope – that you actually moved the reticle by that amount?
Very few scopes – even high-end optics costing multiple thousands of dollars – track perfectly consistently across their entire elevation and windage adjustment ranges. Therefore, the trick is to know where in its adjustment range, and by how much, it is off – so that any discrepancy can be corrected-for.
In reasonably short distances with targets which are not too small or fine, the tall-target test may not be needed to make a good shot. But as distances lengthen, even small discrepancies may mean the difference between making a shot or not making it.
It also bears repeating that BDC scopes – which simply the mathematical calculations needed to make a long-range shot – are usually not going to be precise and accurate-enough once distances lengthen past 600-800 yards. While there are some reticle designs that allow one to hold over and make a shot at that distance, generally one is well-served by dialing in one’s firing solution in the traditional manner, rather than using a BDC, when the distances lengthen significantly.