Shotgun News, 6 August 2007

Practical long-range rifle shooting centers around being able to make first-round hits on unknown-distance long-range targets, while moving through the field, from the best shooting positions available in the terrain. Applications of these skills are both sporting and military.

Competitions in this format are split between describing themselves as "tactical" matches and "hunters test" matches. Examples include Dr. David Kahn's Keneyathlon, the Practical Rifle Team Challenge (CO), the NRA Whittington Center's Sporting Rifle Match (NM), the Blue Steel Ranch Steel Safari (NM), and various "Sniper Challenge" matches around the country. Whatever the name, the crux is delivering first-round hits on unknown-distance targets. With off-the-shelf rifles available for under a grand that will hold one-MOA groups, half the equipment problem is easily solved. The other big decision regards optics.

What optics should you put on your long-range rifle? A scope for practical long-range shooting needs to do the following: provide a clear view of the target area and a precise-enough sight picture; precisely specify hold-over out to the maximum engagement distance; precisely specify wind drift or target lead or trail out to the maximum engagement distance; and allow optical ranging of targets when a laser range-finder cannot be used. The adjustments need to be 100-percent repeatable; the scope needs to retain its zero. Low-light capability is desirable.

When you pick up a scope, the first thing you do is look through it, put the reticle on a target, and get a sight picture. In variable-magnification scopes, there are two types of reticles: first focal-plane (FFP) and second focal-plane (SFP). Most shooters are used to SFP reticles that appear to stay the "same size" as the magnification is turned up and down. Paradoxically, this means that at different magnification settings, the reticle features demarcate different angular distances. For example, if the mil-dots are calibrated at 10x, then at 5x, they would actually mark 2 mils. Confusing? It sure is, and that leads us to the solution: the first focal-plane reticle. The FFP reticle appears to "shrink" as the magnification is dialed down, just as the actual target image shrinks. This constant ratio means that the reticle features are always calibrated; 1 mil is always 1 mil regardless of scope power. The shooter can use the reticle for range estimation, elevation hold-over, and windage hold-off at any magnification setting. The downside of the FFP configuration is that the reticle lines can be too fine at low magnification and too thick at high magnification.

Reticle choice can be a matter of personal preference, but the reticle needs to provide an uncluttered sight picture and not obscure the target. Since the reticle may be used solely, or in conjunction with the elevation and windage knobs, to specify range hold-over and wind correction, it should have marks at regular intervals. These demarcations often take the form of mil-dots or hash marks. Since both the reticle and the elevation and windage knobs specify angular distances, it is important that the "units" match. If the reticle has mil-dots or mil hashes, then the knobs should use 0.1-mil clicks. If the reticle has MOA-based demarcations, then the knobs should use 0.25 or 0.50 MOA clicks. When the units match, there is no math required to convert between using one or the other, and aiming corrections can be done with either the reticle, the knobs, or a combination. The reticle marks used for elevation and windage hold-off should be close enough to provide useful intervals, but not so close as to cover parts of the target. For windage and elevation, marks at 1/2 mil or 2 MOA work well.

The next set of attributes have to do with optical characteristics of the scope. The clarity or resolution of the scope is determined by the quality of lenses and their coatings. Image brightness and low-light performance are determined by lenses, coatings, and the objective lens diameter versus the magnification. The exit pupil is the size of the image coming out of the ocular lens. (Ocular means it's the lens closest to your eye.) If you look at the ocular lens of a scope from a foot or more away, you will see a small area of transmitted light surrounded by black. This is the exit pupil. A larger exit pupil can provide a brighter image to the eye. The maximum size of the human eye's pupil is about 7 mm, so a scope exit pupil larger than that size has no benefit in low light. One advantage of a larger exit pupil not often mentioned is that a larger exit pupil gives more flexibility in eye position to see a full size picture. This is helpful because small head movements do not create the black fringe in the scope view. The other benefit is that it is easier to retain the sight picture through recoil so the shooter can spot his own bullet impacts.

Long-range optics have to provide a mechanism to precisely specify elevation hold-over to compensate for bullet drop past the rifle's primary zero. This can be done by using demarcations in the reticle, by dialing an elevation knob, or by using a combination of those two methods. Reticle design to specify elevation can be as simple as a mil-dot, or as complicated as the Horus H-25 reticle, which has small hash marks every fifth of a mil. Elevation knobs have several properties we care about: click size, total travel, and if it has a zero-stop. For practical long-range shooting, a click size of 0.25 - 0.50 MOA, or 0.1 - 0.2 mil is appropriate. Some target scopes have eighth MOA clicks which are too fine because you'd need 250 clicks to get a 308 to 1000 yards! To emphasize the importance of this point again- the reticle and the knob clicks should be in the same units system: MOA and MOA, or mils and mils!

Next, it is important the elevation knob be able to provide enough travel to get the bullet to the maximum distance the rifle can shoot. Thirteen mils or 45 MOA is enough to take nearly any 308 load to 1000 yards. At Denver altitude, .338 Lapua Magnum takes just over 13 mils to get to 1500 yards. This is where scope tube diameter comes into play; a larger diameter tube allows more erector movement, which in turn allows more elevation.

So you dialed up 43 MOA for your 980-yard shot, which happens to be almost three full turns of your elevation knob, which has 45 fourth-MOA clicks per turn for 15 MOA per turn, then forgot to reset the dial when you left the last shoot position. Now you can't remember exactly which turn your zero was on. You could easily be one or two full turns off, which is over seven feet error at 500 yards! Now what? This is where the zero-stop comes in. When you dial down a zero-stop knob, it will physically stop turning right at or a few clicks under your zero. This physically indicates the zero, and it is much harder to get lost in knob turns. This feature is often paired with a one-turn knob, where the knob provides all the elevation in a single turn, and doesn't go any further.

The other thing long-range shooters have to specify is the windage correction, to compensate for wind drift or target movement. The same considerations apply here as for elevation, except that the amount of travel is not an issue. The reticle is often used for windage hold-off since dialing wind is an extra step and the shooter can usually hold off up to a mil or two accurately-enough to make hits for moderate wind values.

Fixed-power scopes such as the 10x Unertl and the original Leupold Mark 4 used to be the only serious contenders for military-spec sniper scopes due to durability. However, modern high-end variable magnification scopes have no problem with durability. At low magnification, they provide higher speed for close target engagements and more low-light capability. Illuminated reticles are a necessity for low-light shooting, and they are standard on high-end tactical scopes.

How much magnification do you need? The answer is less than you might think. The scope needs to provide a clear image of the target for a well-defined sight picture. With good glass, a 12x scope is more than sufficient for 1000-yard shooting. To test the theory, I dialed down my 3-12x50 mm Schmidt & Bender scope to 4x and was able to make hits on a 36-inch target at 1300 yards; it was enough to discern the target from the background. A lot of people think they need very high magnification to shoot at long range, however, as the magnification is increased, the field of view gets smaller and it is harder to find the target in the scope. Another problem at high power is that the size of the exit pupil shrinks, which makes eye position a lot more critical for a full view through the scope. A smaller exit pupil also makes it harder to track the target though recoil, which is how a shooter can spot his own bullet impacts. At the low end, dialing down the magnification makes it easier to find close and track moving targets, and provides a brighter image in low light. So what's the answer?

For practical shooting to about 1000 yards, a top end of 12x to 16x gets the job done and puts the low end between 3x and 5x for most scopes. Another reason to pick the lowest magnification that will work for the longest shots is to help limit rifle weight and bulk.

Many balk at spending $1000, not to mention almost $3000, on a rifle scope. This is somewhat misguided. While you consume ammunition, barrels, calories, and vehicle fuel in training and practice, the scope, rifle action, and stock are essentially fixed costs. The cost of the consumables will eclipse the fixed costs in just a year or two, while an optic that provides clear and bright images while being boringly dependable will pay off every time you pull the trigger.

There are four scope brands that are particularly common at long-range training and competitions: Leupold, Nightforce, US Optics, and Schmidt & Bender. There are cheaper choices, but I recommend the Leupold Mark 4 line as the baseline choice because it provides the basic features required, is proven by years of duty use, is unlikely to break, and is backed by an excellent warranty.

Leupold's Mark 4 line of long-range scopes includes four variable-magnification models: 3.5-10x40 mm, 4.5-14x50 mm, 6.5-20x50 mm, and 8.5-25x50 mm. They have between 65 and 75 MOA total elevation adjustment which is enough to get .308 to 1000 yards if an inclined base is used. All are available with the M1 knob, which has fourth-MOA clicks in 15-MOA per turn and has no zero stop. The 3.5-10x40 mm models are also available with the M2 and M3 elevation knob, which has one-half or one-MOA clicks. The single-turn M3 knob also has a zero-stop. Leupold only offers mil-based clicks in the 4.5-14x50mm "metric", which has six mils per turn of the M1 knob in 0.1 mil clicks. This scope is the only option for matching click units to reticle units since they have no MOA-based reticles. First focal-plane (FFP) reticles are only available on the 3.5-10x40 mm and the 8.5-25x50 mm.

Next up is Nightforce, whose NXS line of scopes has become very popular with the long-range crowd because of their large elevation adjustment range, thin reticle choices, and reputation for withstanding the extreme recoil forces produced by large magnums equipped with muzzle brakes. The NXS models most appropriate for long-range shooting are the 3.5-15x50 mm, 3.5-15x56 mm, 5.5-22x50 mm, and 5.5-22x56 mm. The larger objective size adds bulk and weight, but helps low-light performance and enlarges the exit pupil approximately 10-percent. The 3.5-15 has 110 MOA of total elevation adjustment and the 5.5-22 has 100 MOA, which should be enough to get .308 to 1000-yards with a level base. The elevation knob has 10 MOA per turn with fourth-MOA clicks. An inclined base is still required for 1400 yards and further for calibers that can make it that far, such as the .338 Lapua Magnum or .50 BMG. To match angular systems, the NP-R1 and NP-R2 reticles are popular with their hash marks every several MOA. Nightforce does not currently offer zero-stop knobs to civilians, and has no first focal-plane reticles.

US Optics, based in Buena Park, CA, is a small manufacturer of custom high-end scopes and was the repair center for the old USMC Unertl sniper scope. While USO has a variety of scope models, their most popular scope for practical long-range shooting is the SN-3 3.2-17x44 mm. These are built to the customer's specs, and are available with almost any combination of tube diameter, knob types, clicks, reticles, and objective lens size. To draw a contrast to the Leupold and Nightforce offerings, with the USO, you can get a zero-stop multi-turn elevation knob with 0.1-mil clicks and a mil-dot or mil-hash reticle to match, or you can get MOA clicks and a MOA reticle if that's how you are trained. With a 35-mm tube, the zero-stop EREK elevation knob typically gives at least 72 MOA up from the zero-stop, which is roughly equivalent to a 100-MOA total elevation scope on a 20-MOA base. Needless to say, the SN-3 has more than enough elevation for any rifle. Priced starting at about $2000, the optical clarity and low-light performance are dramatically better than the Leupold and Nightforce scopes.

Schmidt & Bender's PMII line is a standard to which high-end long-range rifle scopes are judged. S&B is popular with European militaries, and is the issued scope for the British snipers using the Accuracy International rifle. Recently, the S&B 3-12x50 mm PMII won the contract for the new USMC sniper scope. The PMII is also available in 4-16x42 mm, 4-16x50 mm, and 5-25x56 mm configurations, with fourth-MOA or 0.1-mil clicks and a single-turn or two-turn zero-stop elevation knob. The single-turn gives 13 mils in one turn, and the double-turn between 22 and 26 mils total elevation. On the two-turn knob, if the knob is turned to the second revolution, a series of windows at the top of the knob switch to yellow to indicate the second turn is active. Reticle choices are mil-based, including mil-dot and several mil-hash types, and all are in the first focal-plane. Premier Reticle is providing Gen 2 mil-dot reticles for the USMC contract scopes. The PMII provides exceptional optical clarity and brightness. Compared to a similar USO SN-3, the PMII has a slightly larger exit pupil and more eye relief. The PMII is also smaller and lighter than the USO.

After iterating through at least ten of these rifle scopes to figure out what worked best for me, I ended up with three S&B PMIIs. On my .260 Remington and .308 Accuracy International AW rifles, I run the 3-12x50 mm; on my .338 Lapua Magnum, I run the 5-25x56 mm. All have the double-turn elevation knob and feature 0.1-mil clicks, and all have the P4-Fine reticle, which is thin enough to obtain a sight picture on an IPSC target's head (6x6 inches) at 1000-yards. The P4-Fine reticle has hash marks every half mil, which means I can interchange dialing and holding off for elevation and windage easily. The double-turn elevation knob is easy to read and operate; it turns clockwise for "up" - opposite Leupold, Nightforce, and USO - which is more intuitive since the numbers increase left to right, just like we read. The 3-12x50's clarity along with the P4-Fine's simplicity allow good sight pictures on targets out to 1200 yards, and its compact size is a good fit to the short-action rifles. The extra magnification of the 5-25x56 mm is helpful on ultra-long-range targets with the 338 Lapua.

Practical long-range rifle shooting wrings out the rifle to its effective distance and the shooter's ability to make first-round hits in the field. Rifle optics are key to making it happen. While a top-end scope will be a joy to shoot and will be a more effective tool than one you have to compromise on, remember that making hits is about skill and practice, not gimmicks and gear. Now get out there and ring some steel!

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