Scopes and Terms Simplified

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Scopes and Terms Simplified

When I was 11 or 12 and got my first .22, Dad wouldn't let me get a scope for it until I proved I knew how to adjust the open sights to make the bullet hit where I wanted it to. Once I got that first scope and learned how to adjust the windage and elevation dials so my bullet would impact where I wanted, I thought I was done learning. What I learned is that the cheap off-brand scope I bought didn't hold a zero, so I had to upgrade. That was the first of many bad decisions I made when it came to scope ownership.

After I got a scope that would hold a zero, I thought I couldn't miss. Wrong again; high scope rings had the scope high above the barrel and I missed a few really close shots on squirrels that taught me there’s more to shooting than sighting in and just putting crosshairs on the target.

Here are a few things I’ve learned about scopes and some simple definitions or descriptions of words or terms you may hear associated with scopes. I’m throwing in some of my opinions from more of a hunter’s perspective. I’m not a competitive long-range shooter, although I do enjoy shooting long range and have a range with targets out to a mile.

I’m pretty sure at one time or another I’ve owned dang near every scope on the market and still have a hodgepodge of old Tasco, Burris, Nikon, Bushnell, Redfield, and Leupold scopes. Leupold tops more of my rifles than any other brand and I’ve been working with Leupold for a while on educating hunters about some of their products like the CDS system.  I hope this article helps someone make a good decision before buying a new scope or helps a few people avoid a few of the heartbreaking misses I had to endure while learning. 

Second Focal Plane (SFP) vs. First Focal Plane (FFP)

This has to do with where magnification takes place in relation to the crosshairs on variable magnification scopes. I listed the second focal plane first because that’s the one 95% of us have used for generations and are used to shooting.

The magnification takes place on the part of the scope closest to your target on the other side of the actual crosshairs. It sounds fancy and has become a commonly used term lately.

Basically, all it means is that as you zoom up through your magnification range on a variable power scope, your crosshair looks the same. So whether you’re dialed at 4x or 9x, your crosshair size looks the same size.

For first focal plane, the magnification takes place in the scope closer to your eye or before the crosshairs. This makes it appear like the crosshair gets larger as you go up the magnification scale and smaller as you back down. For example, the crosshairs appear larger at 9x than at 4x.

My personal thoughts are that unless you’re a hardcore long-range guy who is shooting over 14x, I’d stick with an SFP. They’re usually less expensive and easier to hunt.

Fans of FFP will argue that with ballistic reticles or drop-compensating reticles, the FFP is better because you don't have to compensate with varying power adjustments. Also, some like the larger-looking crosshair at farther yardages. I’d say there’s no reason to fix or spend more money on a setup that has worked for literally generations of hunters.

Cheek Weld

This is where your head and cheek are placed on the stock for you to comfortably shoot. Having a consistent placement is key to increased accuracy.


Options for reticles (crosshairs or aiming device) have increased over the years - circles, a dot, a mil dot, duplex, etc.  I prefer a duplex reticle that was invented by Leupold in the early 1960s. That is the classic large dark crosshairs that get smaller for fine aiming as you get closer to the center of the crosshair. It’s quick to pick up and easy to see. 

Minute of Angle (MOA) vs. Milliradian (Mil)

MOA: This is a unit of angular measurement equal to 1/60th of 1 degree of a 360-degree circle. The measurement becomes larger the farther away it’s measured. An easy way to remember this is that 1 MOA is basically 1” for every 100 yards. So, 1 MOA at 300 yards is 3” and 1 MOA at 1000 yards is 10”.  If someone says they shot an MOA group at 100 yards, they shot a 1” group.

Before someone has a panic attack trying to correct my math, I should point out that the measurement of 1 MOA at 100 yards is technically 1.047”, but it’s pretty standard to round to 1” per 100 yards. Even at 500 yards, it’s only 5.235”.

It's common now for gun manufacturers to tout that their rifle will shoot sub-MOA groups. If you get an MOA turret, I suggest an MOA reticle to match, as I think it’s easier to match your turret and reticle, especially if you’re making adjustments quickly based on yardage or wind calculations. Most MOA turrets are set at 1/4 MOA adjustments per click, where four clicks represents 1 MOA. 

Milliradian or Mil: This is also an angular measurement. A radian is equal to about 57.3 degrees and there is 1000 milliradians in one radian. To make it easier to understand, basically one Milliradian is 3.599” at 100 yards, or rounded like with MOA, it’s accepted that 1 Mil is 3.6” at 100 yards.

Mil turrets are usually set up for 1/10 mil per click, so every click at 100 yards represents .36”. An easy way to remember is that proponents of the mil turret or reticle like that 1 Mil equals 1 yard at 1000 yards and 1 meter at 1000 meters. 

My thoughts are to get what you like or get used to what you have. Both work great and I have buddies who shoot both and will argue the merits of both until blue in the face. I do suggest if you get a MIL or an MOA turret you get a reticle to match. The comparisons for adjustment are close, so one is not really more accurate than the other.

For example, 1/4 MOA or just one click equals .25” at 100 yards and that same one click at 1000 equals 2.5” of adjustment. Compare that to one click on a MIL scope, which is 1/10 of a Mil at 100 yards, and it’s a .36” adjustment, and at 1000 yards that same one click is 3.6”. 

Eye Relief

This is the distance from your shooting eye to the scope when you see the full field of view. Generally, the more magnification, the shorter the eye relief.

Have you ever borrowed someone else's gun and had to slide your face up/down and forward/back to see through the scope? Well, the perfect distance is the eye relief. It’s a bit different for everyone. Eye relief on binoculars is much closer than on riflescopes, because binoculars won’t recoil back and cut you, so they’re designed differently.

Once I have a comfortable cheek weld, I set my scope at the highest power and slowly move it forward and back to find the perfect eye relief. Then, I confirm that it’s not too close with the gun’s recoil. I prefer 3" from my eye or a little over on larger calibers. 

Scope Height/Mounts

I like to mount my scope as close to my barrel as possible without touching. However, the most important thing is to make sure the height fits your style of shooting. If your scope is mounted too low or too high, you won’t shoot well, nor will you be able to shoot quickly.

I advise starting by closing your eyes and mounting the gun and getting a comfortable cheek weld. Then, start trying different height mounting systems. By adjusting the height to your most comfortable position on the gun, you’ll acquire targets quicker, you’ll shoot more accurately, and the gun’s recoil won’t be as noticeable.

I think cheap rings and scope mounts have caused as many missed shots as cheap scopes. What holds your scope in position is as important as the scope itself. If you drop your gun or it gets banged around, good scopes and mounts should hold their zero in normal wear-and-tear situations.

I like the scope as low to the barrel as possible because I often get point-blank shots while in hunting situations. The higher the scope is from the barrel the lower the bullet impact is at super close ranges. I’ve missed squirrels and shots at coyotes and bobcats due to my bullet impact being a couple inches low of the crosshairs. I’ve since learned to know exactly where my bullet impact is from zero out to as far as I plan to shoot.

Leveling Your Scope/Rifle

If you cant your rifle when you shoot, it will impact your accuracy downrange. On a noticeable cant out to 400 yards, you’ll only be a few inches off. It is, however, an issue that really rears its head on long-range shooting. Leveling your scope and quality scope mounts can help keep you from canting your rifle to compensate for a poorly mounted scope. 

Custom Dial System CDS/ Bullet Drop Compensator BDC

In my opinion, the Custom Dial System I have on most of my Leupold scopes has made me a better shot at all ranges. The CDS and other types of BDC bullet-drop compensators other scope manufacturers have available now have made longer-distance shooting and holdover easy. Wind drift is still yours to figure out, but most of my misses and my clients’ misses when I’m guiding are usually bullet-drop related.  

Some scopes come with a roughly calculated math equation so that once you sight your scope in to a 100-yard or 200-yard zero, you can dial different yardages and hold dead on. You may still need a dope card, but they can be pretty close. Others have websites that make the calculations for you and give you approximate turret adjustments based on the variables you type in.

I call the Leupold custom shop and for around $150, they’ll make a custom turret based on bullet weight, barrel length, distance from center of my scope to center of barrel, feet per second of bullet (printed on ammo box from some manufacturers like Hornady), etc. We even put one on a 30-year-old Leupold my wife's father handed down to her.

In a nutshell, once you send your info in, they’ll send you a Custom Dial Turret you can put on your gun by just unscrewing three set screws usually and dropping the new turret in and tightening it back up. You’re then ready to sight in a 100 or 200-yard zero based on your preference.

Once that’s done and you begin shooting, if your target is 600 yards, just dial 600 yards and hold dead on. You may have to make some small adjustments based on humidity, temperature, and altitude, but you’ll be extremely close and that’s what's so amazing about these setups.

My dad is 72 and last year I had him shooting my Rock River Arms AR chambered in .308. He hit a 15" steel plate from 100 to 500 yards and didn't miss a shot. All he did was dial the yardage and hold right on.

After checking accuracy at the range, my dad made one of his longest shots on an antelope that wasn't letting us close the gap. It was a little over 300 yards, but he was able to dial the yardage and hold dead on. He made a perfect one-shot kill and was forever sold on the new CDS technology. As for me, it was fun watching him learn a new system. It’s funny how things come full circle sometimes.


Fred Eichler

Fred’s passion for bowhunting has taken him all over the world. He truly believes that any animal with a bow is a trophy, and his personal quest to complete the North American Super Slam with a recurve bow reflects that state of mind. In August of 2009, Fred harvested a cow Tule Elk to become the first person to take all 29 North American big game species with a recurve bow. Fred has been fortunate enough to share his love and enthusiasm of the sport with fellow bowhunters across the country through television shows and personal appearances. If you ever run across Fred in the woods or at your local bow shop, you’ll be greeted with a sturdy handshake and a big smile.

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