Scope Reticles and Focal Planes Explained
September 15, 2019
The first question any of us must answer when choosing a reticle is which end of the scope's magnification range we expect to use the most.
There are so many reticle choices these days that it can be difficult navigating through all the options. Not only must a shooter contend with choosing between first-focal-plane (FFP) reticles and second-focal-plane (SFP) reticles, they also have to choose between traditional crosshair and so-called “Christmas tree” or “holdover” models.
The first question any of us must ask ourselves when choosing a reticle is which end of the scope’s magnification range we expect to use the most. This is by far the most overlooked aspect of reticle selection, yet it drives the choice between FFP or SFP reticles.
The best guidelines when selecting a reticle are to identify what magnification range you want and where you’ll expect to spend most of your time in it. Most competitive precision rifle and recreational shooters fall into the maximum-magnification category and are best served by a FFP reticle. Hunters should first look to SFP reticles.
So often new scope customers that can afford it choose FFP reticles because they’re the popular ones to use today. But they’re not always the right choice. However, if the scope you’re considering has a maximum magnification of more than 10X and you plan on living in the top half of the magnification range, FFP reticles are the way to go.
At magnifications greater than 10X, humidity and high temperatures can make it necessary to dial down magnification in order to see more clearly. It’s nice to be able to dial away from maximum magnification and still have a reticle that subtends correctly. Also, dialing down magnification increases field-of-view, so a FFP reticle remains useful when a little-less-than-maximum magnification is desired for more field-of-view.
FFP reticles have the greatest visibility at maximum magnification and get steadily smaller as magnification decreases, but they remain most usable in the top half of their magnification range. By the time magnification gets well below half of the total range, the reticle is frequently so small that it’s difficult to see. This is why FFP reticles are not the best choice for most hunters and law enforcement (LE) snipers.
SFP reticles stay full-sized no matter where the scope’s magnification sits. This means they only subtend correctly at one power. (Frequently at the maximum.) Any scope with a 10X maximum magnification or less is ideal for SFP use because they aren’t commonly applied to measure with the reticle, and if they are, will likely be at maximum power anyway.
Hunters and LE snipers frequently sit at the low end of the magnification range because of the wide field-of-view. Both shooting demographics need to be able to clearly see the reticle at minimum power because that’s where their shooting needs to happen the fastest. There’s always time to turn magnification up when the target is far away, but never time to turn it down if the target is right in front of you.
As an example, a hunter has to be ready for their quarry to appear at 50 yards, so he’ll likely have magnification turned all the way down. This low magnification makes it very difficult to see the reticle in a hurry if he is using a FFP reticle. LE snipers shoot average 50 yards when deployed, yet they spend hours looking through their scope. The large, easy-to-see SFP reticle ensures LE snipers can be at minimum magnification while still remaining ready to shoot.
Once a scope consumer wades through the FFP versus SFP argument, the next issue to resolve is whether a crosshair recticle or holdover reticle is in order. The best-known crosshair reticle is the duplex, which has wide lines that transition to fine crosshairs near the middle of the reticle. It is the simplest to use, but only offers one prominent aiming point.
The most recent and popular crosshair reticles subtend in either millliradian (mil) or minute of angle (MOA) and have either .2-mil or 1-MOA increments. This allows the shooter to dial for distance and have very precise hold-off points for windage. A small floating dot in the center of the reticle is also a newer and note-worthy feature because it gives the shooter a precise aiming point on even the smallest targets. The old duplex reticle will completely cover a 1 MOA target, so the newer thin crosshair reticles are well worth any shooter’s attention and consideration if precision riflery is on the menu.
Holdover reticles are faster to use than traditional crosshair reticles, but also require a transition period. My first exposure to holdover reticles came during a U.S. Marine Corps Scout Sniper Advanced Course in 2006. I observed a Horus reticle (horusvision.com), and while I understood the concept, I wasn’t a big fan. I was used to looking at the uncluttered mil-dot reticle and didn’t like having so much reticle to look through to see my field-of-view. My opinion was pretty typical for a first-time holdover-reticle experience.
Today, my favorite reticle for most of my shooting is Leupold’s Tremor 3, also in use by U.S. Special Operations Command (SOCOM) snipers. It has a lot of sensible features, but can also be overwhelming. I like it because it allows me to transition quickly from one target to the next without having to twist the elevation turret or disturb my shooting position. It also has “wind dots” that allow for rapid and accurate wind estimation from any distance.
Recently, there has been a new series of reticles that fall into the holdover category, but have significantly fewer aiming points than the Tremor 3. These reticles are less cluttered, but many who use them fail to realize that unless a portion of your reticle is touching your target, you do not have a repeatable point-of-aim. This makes follow-up-shot corrections very difficult and much less precise when it comes to any reticle with too few aiming points.
Reducing the number of aiming points on a holdover reticle by eliminating portions of the reticle makes a floating point-of-aim much more likely. I don’t care for reticles that adopt this strategy because they‘re only effective on very large targets, like a full-sized International Practical Shooting Confederation (IPSC) piece of steel set at 800 yards or less. However, they are growing in popularity by those transitioning from traditional crosshairs to holdover-type reticles, even with their limited utility.
Crosshair versus holdover reticles is a personal affair and depends entirely on whether the shooter wants to dial for elevation or just holdover. Each type has its merits. I holdover about 75 percent of the time, so about 75 percent of my scopes have holdover reticles. I believe every rifleman should try to be proficient in both reticle languages.
Regardless of which type of reticle one selects, FFP and SFP are going to be well served by .2-mil or 1-MOA subtension along the main horizontal crosshair, and a floating center-dot or ultrafine crosshair in the very center of the reticle. By obscuring the smallest amount of the target, it ensures you can shoot as small of a group as possible when load or accuracy testing. It also has precise hold-off points for wind correction.
Of course, there’s still room in the optics world for the old duplex reticle. If a guy isn’t shooting past 300 yards and sticks to hunting or plinking, all this reticle hoopla doesn’t apply. More critters and cans have fallen to a duplex reticle than any other type, and that’s not likely to change anytime soon.