Precision Shooting Magazine - May 2008 (Vol. 56 No. 1)

As I recounted in Part 1 of this series, learning to shoot sniper rifles out to 2000 meters exposed just how much I’d never learned about shooting. Besides highlighting my poor math and science skills, the long range classroom imparted useful lessons about different guns, cartridges and other equipment. My R&D efforts have always resulted in more questions created than answered, so I’m far from being one to write a “How To...” on this subject. What I can offer is more feedback about some of the specialized equipment necessary in this pursuit. Over the years I’ve dealt with a few companies that don’t appreciate constructive criticism about their products. So in the interest of brevity and ultrasensitive personalities I’ll keep this installment relative to items I tested or employed that actually worked. This brand of marksmanship is a “Shooter Beware” prospect. There are cartridges and guns falsely advertised and demonstrated as the long range solution. You can trust that despite much hard work by very talented professionals, no one has found the “Holy Grail” at 2 kilometers yet. Anyone that claims otherwise probably has a healthy supply of snake-oil gun lube they’ll throw in to sweeten the deal.

It’s been my experience that the most controversial subject in long range shooting is that of the right cartridge. The real answer is there’s not one perfect caliber or load. There are both good prospects that deliver and dismal failures that succeed in advertising only. The good news is that folks pursuing the elusive “One Mile Shot” have several choices. It’s likely that more options will emerge as time and technology progress. When I got involved in this endeavor several years ago, I had only the .338 Lapua Magnum (LM), .408 CheyTac® and the already fielded .300 Win Mag (WM) and .50 BMG sniper systems to work with. Of those, .338 LM and .408 advertised the most promise but offered the fewest options at that time.

While not likely to win the long-range crown, .300 WM is worth discussing as a natural starting point. It’s a favorite among snipers blessed with access to it, and for good reason. The traditional tactical load allows match grade 190 gr. Sierra MK projectiles with BCs in the .588 range to reach muzzle velocities (MV) around 3000 fps. The result is flatter trajectory, shorter flight time and decreased wind effects when compared to the conventional .308 Win. At standard atmospherics (59 deg F, 78% humidity, 29.53 in Hg) with a MV of 2950 fps, these projectiles decelerate to the speed of sound (1117 fps at this temp) around 1375m. This load is phenomenally accurate out to 1000m with operational evidence of it far exceeding that range in the right hands and platform. Despite many years of experience shooting issued .300 WM rifles, I wasn’t savvy enough to put more R&D effort into giving this cartridge longer legs. Fortunately there are professionals currently doing good work in this arena with heavier projectiles and different barrel configurations. The US Army would do well converting the soon-to-be mothballed M24A1 into Remington Arms’ .300 WM, M24E (Enhanced) configuration. Not only would this re-chambering extend the Army sniper’s effective range to 1000+ meters, Remington’s external box magazine conversion would be a welcome addition to the system. Though there’s a practical limit to this cartridge’s effective distance, overall it’s solid for sniping and further development may bring renewed interest in employing it “out yonder”.

My last article provided an abbreviated history of the .338 LM. This cartridge has emerged as the favorite among tactical shooters eager to move into the 1500m (+) neighborhood. Availability of factory loads is rising steadily, hand-loaders have access to quality brass and high BC projectiles run the gamut from 250 to 300 grains. This magnum requires use of a long action (LA) and there’s some debate in the industry as to whether or not it’s safe to convert LA rifles to .338 LM. I’m not technically adept enough to weigh in but I’ve noticed most manufacturers are building receivers specifically for this size cartridge. One problem that has plagued some .338 LM shooters- and I learned the hard way- is not all .338 LM cartridges are alike. For reasons I’ll never understand, two different overall lengths (OAL) are available. I only know of one manufacturer requiring the shorter OAL: Accuracy International. I can vouch for AI’s reputation for phenomenal durability and accuracy in smaller calibers. But their .338 LM rifles suffer from magazines too short for the longer dimension. Last year SAAMI followed the CIP specification for an OAL of 93.5mm or 3.681”, which is the longer load. Overall this should be positive due to more powder capacity and projectiles being seated closer to the rifling. Some factory loads are available in either length so it pays to know which fits in your rifle. Fortunately most new .338 LM rifles are designed for the SAAMI specified OAL. These guns will generally feed the shorter .338 LM loads reliably but accuracy may suffer due to the increased jump to lands and grooves. At a minimum, potential muzzle velocity suffers due to lighter load possibilities. Instead of confusing readers with different measurements, suffice it to say you need only focus on the SAAMI number. I’ve heard explanations from representatives in both the firearms and ammunition industries as to why the shorter length was created but I haven’t heard what advantage it provides. I suspect the wonders of the free market will correct this problem in the long run. I’ve heard from the ammunition industry that AI is presently developing a remedy for their guns, but as of this writing have no direct confirmation from them.

In terms of verifiable performance, the .338 LM shows itself to be an accurate long-range system with sub MOA capabilities between 1000 and 2000m. Because its action is significantly smaller than those in the .40 to .50 range, rifles are accordingly more compact and lighter. Best of all, the choices in .338 LM firing platform are on a near-meteoric rise. Prices range from the mid $2K range all the way up to $8K+ for rifles alone. One new example is Remington’s M24A3 seen in Photo 1. This version of the venerable M24 system is built on a new action, complete with external magazine. This is just one example of several new developments on the market today. On the ammunition front, Ruag’s diverse line of Swiss P sniper munitions offer matching close-range trajectories within a caliber and proven long range accuracy. The armor piercing (AP) cutaway in Photo 2 is one example with excellent performance. This load shot better for me at 1500m than several manufacturers’ conventional match loads.

Successful Sightings

There’s no doubt any great rifle/cartridge combination can be hamstrung by poor ancillary equipment, particularly the riflescope. To find out if your favorite optic is up to the task, simply thrust it into the long range crucible. There’s no better place to expose poor design, inferior lenses, reticle shortcomings or structural weakness. Here again price is not always concurrent with quality and capability. I’ve been stuck on a deployment with a $2300 scope whose sole strength was the manufacturer’s claim it could survive being driven over by a truck. I’m pretty sure that’s the dumbest advertising gimmick I’ve ever seen associated with precision shooting equipment. I’ve also used tactical optics in the $800 to $1200 range worth twice that amount when compared to their competition. Needless to say it pays to shop around and ask questions of people with practical experience in this arena.

A scope’s design dictates its ability to support long range shots. At distances beyond 1000m, any limit to elevation adjustment becomes a serious problem for someone dialing in corrections. One method is to use sloped scope bases or rings, normally with 20 to 40 MOA built in. An un-sloped optic with 65 MOA total elevation adjustment doesn’t leave all that travel available for come-ups after zeroing. A sloped mount places the scope’s erector assembly at a point where more elevation adjustment remains usable once sighted in. Lacking this, if a shooter intends to dial in elevation using a ballistic drop compensating (BDC) or target knob, elevation will hit the upper limit prior to maximizing capabilities of the rifle, cartridge and [hopefully] shooter. Before I discovered sloped rings I tried to outsmart my optics by using 500m or 1000m zeros. I thought this would provide the extra adjustment needed, with vertical stadia marks permitting hold-under points for closer ranges. I found the reality is that any distance bought on the far end isn’t worth the near end trade-off. For example, when shooting Lapua’s 250 gr. Scenar at 2950 fps with a 65 MOA scope, a 100m zero runs out of elevation at 1300m- and that’s assuming you have all 65 MOA available after zeroing, which you won’t. Using a 500m zero, the upper limit is only 1450m. A 1000m zero allows maximum adjustment to 1675m, but you have to factor in a 100m target now requires dialing down 40 MOA to engage. If you’re in this situation go straight to a sloped base or ring set to conserve time and to limit the need for expletives. Several new, high quality optics provide internal adjustments of 100 MOA or more, so this problem may become less significant for die-hard BDC fans.

A better option for long range “dope management” is to use reticle holds. While I’m not a fan of purpose-built reticles calibrated for one gun and load, there are folks that still swear by them. If you plan to shoot one rifle, with a specific, repeatable load in the same atmospheric conditions 100% of the time, a custom reticle might actually provide you requisite accuracy. But if you’re like 99% of the shooters requiring accurate shots past 500m, this option won’t work for you. Back when my body moved faster than my brain, I preferred purpose-built reticles because they’re so easy to use. The fact that I’m inherently lazy probably had something to do with it too. However I’ve since learned that when engaged in serious pursuits, the flipside of “Easy-To-Use” is usually “Not-Worth-A- Damn”. For military weapons such as crew-served and short range carbines, custom reticles can be handy because they take little thought and anyone can use the holds without knowing gun-specific data. However accuracy suffers anytime the weapon system is fired in conditions other than those the reticle holds were calibrated for. Barrel wear and lack of ammunition consistency also play havoc on accuracy, so it’s hard to envision where a purpose-built reticle makes sense when precision is called for.

The best reticle hold option for elevation, windage and moving targets is with detailed mil reticles subtending from .5 mil down to .2 mil. In general, the more detailed the reticle the more accurate all measurements incorporating mils will be. An easy way to understand this is to compare these reticles to a ruler. If you measure something with a ruler marked only in inches, you’ll have to estimate any measurement that falls between markings. But if you add markings every 1/8” your measurement will be accurate within to that 1/8”. The same is true for mils and can be seen in the accompanying images of basic mil-dot (Photo 3) and Horus Vision H37 (Photo 4) reticles. Though complex at first sight, the Horus reticle provides tremendous functionality for long range target engagement. It has 41 mils below center, and the reticle’s stadia intersection is actually 4 mils above center, providing more hold-over at max power (in a 1st FP scope). A key advantage beyond the .2 mil subtension is that wind holds and moving target leads at any distance are easily handled by use of mil markings left and right of the center stadia. A standard mil-dot reticle requires a shooter using mil holds to guess for winds or leads and in this game, guesses tend to beget misses.

If the current rage for huge objectives and ultra-high power scopes were any indication, I’d guess everyone in the US is trying to shoot deer in a neighboring county. Long range shooting is one of the few places where 50 to 56mm objectives and 20x scopes are actually warranted in the field. However, too much power can be counter-productive, particularly in low light or high mirage conditions. Fortunately high quality variable scopes are available that allow dialing down to the 12-20x range, providing better light transmission, fields of view and a steadier images. In most cases shooting targets in the neighborhood of 1500m can be handled at 14-16x just fine.

A final comment on optics is that to make full use of a mil reticle, elevation and windage adjustments should be in mils. That doesn’t make much sense until you realize 10 clicks on a .1 mil increment turret equal 1 mil of impact shift at 100m. As it turns out, the mil reticle subtends very well to metric measurements. One milliradian equals 10 centimeters at 100m, making a mil reticle scope with centimeter (.1 mil) adjustments a useful set-up. The reticle allows you to measure exact distance in any direction from point of aim (POA) while zeroing. The .1 mil adjustments allow dialing those measurements exactly as measured with the reticle. I’ve zeroed rifles with this setup in 2 to 3 rounds on almost every occasion I’ve used them. Rifle scopes in the US normally have MOA-based adjustments and I suspect I’ll get loads of disagreement from most quarters on mil-based clicks, except from shooters who have discovered their true functionality. Don’t get me wrong, I don’t speak French or pay my bills in Euros. I’m old enough to remember that we were supposed to be on the metric scale by 1976 (I was in 2nd grade). I still think and speak in inches and MOA (except when measuring shooting distances in meters). I’ve simply realized I’m more effective in precision work when my reticle subtensions match my scope adjustments. With the ultimate utility of the mil reticle, this necessitates clicks in tenths of a mil and now that I understand why, that makes perfect sense. Despite that rationale, I suspect it will be many years before centimeter clicks are a common offering on US-made optics.

Beyond guns, bullets and scopes, several important items can make or break long range precision work. Even the usually overlooked muzzle brake takes on new significance. As with all tactical rifles, a balance must be achieved between braking felt recoil and reducing signature. Unfortunately one need is often sacrificed for the other and a lopsided compromise results. Flash suppression generally trumps muzzle braking on assault rifles, battle rifles and carbines. On larger guns the need to return to target quickly for shot observation and potential follow up gives muzzle braking greater importance. The hard hitting nature of these calibers also necessitates braking to aid accuracy and limit shooter wear and tear. I’ve spent a lot of time behind one particular brand of .338 LM rifles and found that changing from the company’s standard muzzle brake (no more than a machined and ported pipe) to their baffled brake reduced felt recoil to below that of a .300 WM. Performance of the better brake was immediately evident with reduced group sizes and my ability to frequently put in long range sessions. Military snipers are finding that well designed sound suppressors tame muzzle blast, flash and felt recoil. The added sound reduction becomes a secondary benefit in many cases. One drawback is increased overall rifle length, sometimes making it too unwieldy to carry long distance with the suppressor installed. Sound suppressors have additional unique considerations worth weighing, such as zero shift and muzzle interface choices, but overall they provide significant advantages.

Previously I touched on the fact that a good ballistic computer can make nearly every aspect of a sniper’s trade more efficient. Even much of the sniper “Old Guard” has embraced their utility. I suspect that like me, once shooters get hands-on time with any of the good programs and devices, their utility becomes apparent. Whether using a hand-held device, laptop or desktop computer, enough information can be gleaned from these applications to greatly enhance chances of a first shot hit. I’ve worked with many of the current programs and devices available and there are pros and cons to each. Most provide elevation and wind corrections, moving target leads, angle/slope calculations and atmospheric corrections. I’ve had the greatest laptop/desktop success with Sierra’s Infinity and Perry System’s Exbal. Both provide detailed information about most commercially available projectiles and allow input of custom bullet data, providing endless functionality. Other important data such as maximum range, point-blank range, bullet path and range calculations can be gleaned (plus much, much more).

For handheld ballistic computers, programs from Horus Vision and Perry Systems are user favorites. Both are Pocket PC compatible, providing portability and convenience at the range or in the field. I have more experience with Horus’ A-tragMX, but I know long-gunners just as happy with Exbal. For long range shooting the edge goes to A-tragMX due to an ability to calculate both spin drift and coriolis, which are critical at ranges beyond 1000m. Both programs allow input of multiple ballistic coefficients (BC), which helps to fine-tune the firing solution since BC changes throughout the projectile’s flight path and must be accounted for.

A final point about ballistic programs is that they are neither replacements for learning to develop data manually nor required to make the shot. Rather they complement the shooter’s equipment and speed up the process of developing data for different distances, environments and loads. It’s both common practice and recommended to fall back on the tried and true logbook or “dope card” affixed to the rifle, complete with come-ups for the individual shooter, gun and primary load. All electronics fail and many situations don’t allow their use in the first place.

A good quality atmospheric measuring device goes hand in hand with the ballistic computer. The gold standard for tactical shooting is the Kestrel 4000 Pocket Weather Tracker, seen in Photo 5. The critical elements needed for inclusion into a ballistic program are ambient temperature, barometric pressure and humidity, often expressed as “TBH”. These mini weather stations also provide an anemometer function, measuring wind at the shooter’s position. Although experience in a particular environment and a quality thermometer can provide the shooter enough information to get by, having a small, light and element-resistant device like the Kestrel makes quick work of accurate measurements.

I mentioned in Part I that I learned I could shoot the .338 LM better off the ground, either supported with a bag rest or bipod. The preferred type of rest is as individual as a favorite driver in NASCAR. Some accuracy buffs swear by the bench, others like to isolate their rifle with a vice-like rifle rest and a few oddballs like me are more comfortable lying on the belly. Whatever your preference, a good support can certainly help tighten up groups out at distance. If using a bipod, resist the urge to go big and bulky just for sake of strength. I’ve seen too many poorly designed bipods hamper the performance of a $5,000.00 rifle that would otherwise turn in excellent accuracy. If shooting in anything other than static range conditions, a good bipod design allows independent adjustment of leg length to accommodate uneven terrain. If you routinely lose skin on your hands each time you adjust those legs, invest in a different bipod. The ability to cant the rifle slightly is also useful to account for small angular corrections, but this adjustment has to have enough tension to prevent a top heavy rifle from flopping around when not on the shoulder. Lastly, the bipod ought to be under some type of spring tension when folded so it doesn’t rattle. Whether stalking on a hunt or moving into a tactical position, a noisy bipod is a liability.

Although there’s a genuine lack of expertise in the shooting industry about extended range precision work, the landscape is improving. Instructors, military personnel, R&D specialists and industry representatives increase the collective knowledge base daily. If you’re planning to get into this shooting genre, your expectations must be reasonable. I mentioned previously that the learning curve is actually straight up and this general knowledge void doesn’t make that ride any easier. Additionally, shooting equipment for long range work tends to be expensive. The best you can do to get through the trials and figure out the tricks is to study what really works for other shooters and then experiment for success. At the end of the day a little patience and a lot of hard work will go far towards making your precision shots count, well into the next grid square.

Steve Adelmann is a freelance writer, former Special Operations Sniper and 21 year veteran of the US Army. He owns Rifleman Consulting: teaching and consulting to citizens, the firearms industry and the US government. Go to http://www.riflemanconsulting.com for more information.