Back in the 1960s, when I was a young shooter, variable-power riflescopes were fairly new and widely distrusted. In those days there were reasons for that!
They may or may not have been more fragile and less reliable — I honestly don't know, although that was believed at the time — but point-of-impact shifts as you changed power settings were normal. In those days we clung to our fixed 4X scopes, and I didn't own a variable until the mid-1970s.
The variable-power scope has long since been perfected. Point-of-impact shifts between power settings are rare today and nonexistent in quality scopes, and variables are by far the most common riflescopes now in use. And why not? Turn it down to a low setting for close-range work; turn it up for distant targets.
Just remember, even in wide-open country you never know when you might get a close shot, so it's always wise to keep your power setting low until you actually need more magnification! Here's the deal: With variables you always get a wider field of view at lower magnification settings, allowing faster target acquisition€¦and if you have a modern high-magnification variable turned up all the way and a deer jumps up at point-blank range, there's a good chance all you'll see through the scope is a blur of hair.
For many years the practical technological limit on variable-power scopes was "three times zoom" so, historically, the 3-9X became the world's most popular riflescope. It remains an extremely versatile choice — at 3X most people are okay even at very close range, and for big-game hunting 9X is enough for most purposes.
Of course, there have long been less-powerful variables intended for close-range work (such as dangerous game). The popular 1.75-5X a good example. And there have been more powerful variables for long-range work and varmint hunting, such as 6-18X.
Today things have changed. "Three times zoom" is no longer the limit, with four-, five-, and even six-times-zoom variables now available. This greatly expands the utility of a variable-power scope. At long range in open country, and on small targets, like woodchucks and prairie dogs, there is really no limit on how much magnification you might use, although with mirage and heat waves — which are magnified right along with the target — there may be a limit on how much magnification you can use.
However, with a scope to be used for big game you simply must have a low enough setting to allow close shots when necessary. So, modern scopes with greater zoom capability, such as 4-16X, 4.5-14X, 3-15X, and 3-18X, offer unprecedented versatility.
Choice of reticles is important. The finer the intersection of the crosshairs, the more precise the aiming point can be because less the target and aiming point is subtended — obscured — by the reticle. However, extremely fine reticles are increasingly hard to see in low light. So, while a very fine crosshair may be ideal for varmint hunting, for big game a compromise must be reached between precision and visibility.
There remain numerous options in reticles, from very fine crosshairs for target reticles to extremely bold reticles for fast acquisition on dangerous game. In general, however, the people have spoken: The most popular reticle today is the "plex-type" with thicker outer wires for visibility and a thinner intersection for precision. The reason this type of reticle is so popular is simply because it is so versatile! That said, lighted reticles are becoming more popular, and indeed they are wonderful for fast target acquisition, especially in low light and shadows.
Thanks to tremendous interest in long-range shooting other options seen more frequently include dial-up turrets and/or reticles with additional aiming points for holdover. Provided adjustments are absolutely consistent "dialing the range" or holdover is probably more precise€¦but also a bit more time-consuming and, in the field, when you plan to take a shot and then the situation changes, it's all too easy to forget to dial back down. So, for hunting situations at normal ranges, additional aiming points are faster and simpler.
There are numerous systems, with additional stadia lines the most common. Nikon, however, uses see-through circles in their BDC (Bullet Drop Compensation) reticle, which means that the exact aiming point is not obscured. But that's not all. In addition to the aiming points in the center of the circles, the reticle also provides aiming points at the top and bottom of each circle as well. The accompanying graphic shows this "expanded view" of the reticle very well, and underscores the precision that a shooter can use to his advantage on smaller targets at longer distances.
I've just been shooting with their new Monarch 3 BDC Distance Lock riflescope in 4-16X zoom capability with a trim 42mm objective lens and standard one-inch tube. Needless to say, there are no flies on Nikon glass, but this is actually a very mid-priced riflescope with a lot of great features.
The main reticle is a "plex"-type with thick outer horizontal and lower vertical crosshair and a smaller intersection and upper vertical crosshair. Below the intersection and above the thick portion of the wire are four circles for aiming points, with the top of the thicker portion of the crosshair acting as a fifth aiming point.
The 4-16X capability is extremely versatile and certainly not new, nor is the BDC reticle new. The Distance Lock feature, however, is new. The difference is that the reticle is in the first focal plane. Although long seen on some European riflescopes, most variable scopes seen in the United States have the reticle in the second focal plane. What this means is that as the variable power is turned up, the reticle does not change in size. Visually this is not a bad thing, as the aiming point seems to become finer as magnification increases.
However, on scopes with additional aiming points the reality is that, with a second focal plane reticle, the exact distance values of those aiming points change as magnification is increased or decreased. The reason for this is that, since the reticle does not magnify it covers or subtends a different amount of the target at each power setting. Some systems compensate for this by assuming maximum magnification, while other computerized programs recommend optimum magnification or can yield a different set of values for each power setting.
Nikon's BDC Distance Lock moves the reticle to the first focal plane, so that it visually becomes smaller or larger as you decrease or increase magnification. This means that either the main crosshair intersection or the additional aiming points subtend the same amount of the target at all power settings€¦so the distance values of your aiming points remain constant.
This probably doesn't sound like a big deal, but using this particular 4-16X scope as an example, there are many occasions when heat waves and mirage may make it impossible to use all the magnification available€¦but it may still be possible to take a long-range shot at lesser magnification. The BDC Distance Lock is thus one less thing to worry about.
What you do have to worry about with any range-compensating reticle that uses aiming points is knowing at exactly what range each aiming point is valid with your load. So, I put the BDC Distance Lock 4-16x42mm scope on a Ruger American in .243 Winchester. That is most definitely not a long-range big-game round€¦but it's an excellent long-range coyote and varmint cartridge. I was shooting Hornady Superformance with a 95-grain SST bullet.
The end flap tells me my velocity should be a speedy 3185 feet per second (fps)€¦but just to be sure I cranked up my Oehler chronograph. My actual velocity was a bit slower, averaging 3121 fps. That's not a knock on Hornady€¦most American published velocities are for a 24-inch barrel. My rifle has a 22-inch barrel, so it's going to be a bit slower. The end flap also suggested I should sight-in 1.3 inches high for a 200-yard zero, so that's where I adjusted the zero.
The next step: Back to the house and jump on the computer! I got onto the Nikon Spot On Ballistic Match Technology website, (also available as a smart phone application). Most loads and bullets from most manufacturers are in there, so I plugged in a 95-grain Hornady SST and plugged in my actual velocity. I could also set it for different atmospheric data — hot, cold, altitude — but I was pretty close to sea level on a balmy day, so for this exercise I left it alone.
Okay, with a 200-yard zero here are the values it gave me: The uppermost aiming circle is valid at 287 yards, then 382, 464, and 575€¦with the top of the thick wire, used as a post reticle, valid at 670 yards. Simple€¦except there's just one thing. As the box flap suggested, I zeroed 1.3 inches high. This starts the ball rolling, except the load was a bit slower in my rifle, so I actually needed to be 1.41 inches high. I better hurry back to the range and fix that€¦provided either me or my rifle are capable of holding that extra tenth of an inch!