Eurooptic vortex burris nightforce sale




teslong borescope digital camera barrel monitor


As an Amazon Associate, this site earns a commission from Amazon sales.









January 30th, 2016

Wind Reading Resources from JarHeadTop’s M.Sgt. Jim Owens

Readers often ask for a good, authoritative resource on doping the wind and reading mirage. Many Forum members recommended M.Sgt. Jim Owens’ Wind-Reading Guide. With 22 sets of wind charts, this is offered for $14.95 as a printed book or $12.95 in CD format. Owens’ Reading the Wind and Coaching Techniques clearly explains how to gauge wind speeds and angles. Owens, a well-known High Power coach and creator of Jarheadtop.com, offers a simple system for ascertaining wind value based on speed and angle. The CD also explains how to read mirage — a vital skill for long-range shooters. In many situations, reading the mirage may be just as important as watching the wind flags. Owens’ $12.95 CD provides wind-reading strategies that can be applied by coaches as well as individual shooters.

As a separate product, Owens offers a Reading the Wind DVD for $29.95. This is different than the $12.95 CD. It is more like an interactive class.

Played straight through, the DVD offers about 75 minutes of instruction. M.Sgt. Owens says “You will learn more in an hour and fifteen minutes than the host learned in fifteen years in the Marine Corps shooting program. This is a wind class you can attend again and again. [It provides] a simple system for judging the speed, direction and value of the wind.” The DVD also covers mirage reading, wind strategies, bullet BC and more.

Permalink - Videos, Shooting Skills No Comments »
August 24th, 2015

Long Range Shooting Error — Why People Miss

Bryan Litz Applied Ballistics Long Range Shooting Error Wind Call Kestrel Laser Rangefinder

Applied Ballistics has created a new series of YouTube videos about precision long range shooting. Featuring ace long-range shooter and professional ballistician Bryan Litz, these videos address various topics of interest to long-range marksmen. In this week’s video, the second in the series, Bryan Litz examines the most common causes of ballistics shooting errors at Long Range.

Watch Applied Ballistics Video about Common Mistakes in Long Range Shooting:

Bryan Litz of Applied Ballistics often hears the question: “What are the main reasons people miss their target at long range?” To answer that question, in this video, Bryan explains the most important variables in Long Range shooting. Bryan says: “Probably the number one thing is range — you have to have a [precise] range to your target because your bullet is dropping, and to hit the target you need to correct for bullet drop.” Distance may be indicated on the target bay (or berm), but for open ranges you should ascertain distance-to-target with a quality laser rangefinder. Even when the distance to target is shown with a sign or marker, you may want to confirm the distance with your rangefinder. (You may be surprised — we’ve seen marked target distances at commercial ranges off by 25+ yards!) Bryan says: “Get a good laser range to the target and you’ll be within a couple yards”.

Bryan Litz Applied Ballistics Long Range Shooting Error Wind Call Kestrel Laser Rangefinder

After distance to target, the most important variable is the wind. This is the most challenging factor because the wind is constantly changing. Bryan explains: “After 300 or 400 yards, the wind [will] move your shots off the target if you don’t correct for it. The best way to account for the wind is to measure it at your location with a Kestrel. The Kestrel can give you the speed and direction of the wind at your location, which can baseline your wind call for your long-range shot.” Bryan acknowledges that there will still be variables: “The wind isn’t always blowing the same downrange as at your location… and the wind is always changing”. Bryan notes that you need to account for variances in wind between the time you gauge the wind angle and velocity and the time you actually you take your shot.

Permalink - Videos, Shooting Skills 11 Comments »
February 17th, 2015

Brain Teaser: Do You Know the Rule of the Square?

wind drift wind reading 6mmbr rule of the squareHorizontal Wind-Drift vs. Distance
OK, here’s a challenge question for you.
Let’s see if you get it right.

Q: If the wind is blowing 10 mph from 9 o’clock and if my horizontal wind deflection is 0.7 inches at 100 yards, what is the horizontal drift at 1000 yards?

You may be thinking, “Well, since the target is ten times more distant, the wind-drift should be around 7 inches, maybe a little more since the bullet will be slowing down.” That sounds reasonable, right?

WRONG.

As you move from near to far, the increase in lateral deflection (from a 90° crosswind) is (roughly speaking) a function of the square of the multiple of distance. If your target is two times farther away, you use the square of two, namely four. If your target is five times farther away, you use the square of five, or twenty-five. In this example, the increased wind drift (from 100 to 1000 yards) is at least 0.7″ times (10 X 10) — over 70 inches (give or take a few inches depending on bullet type). We call that the Rule of the Square. This Rule lets you make a quick approximation of the windage correction needed at any yardage.

Precision Shooting and the Rule of the Square
I was going through some back issues of Precision Shooting Magazine and found many references to the Rule of the Square. This made me curious — I wondered how well the Rule really stacked up against modern ballistics programs. Accordingly, I ran some examples through the JBM Ballistics Trajectory Calculator, one of the best web-based ballistics programs. To my surprise, the Rule of the Square does a pretty good job of describing things.

EXAMPLE ONE — .308 Win (100 to 400 Yards)
For a 168gr Sierra MK (.308), leaving the muzzle at 2700 fps, the JBM-predicted values* are as follows, with a 10 mph, 9 o’clock crosswind (at sea level, 65° F, Litz G7 BC):

Drift at 100: 0.8 MOA (0.8″)
Drift at 200: 1.6 MOA (3.3″)
Drift at 400: 3.4 MOA (14.4″)

Here you can see how the Rule of the Square works. The rule says our drift at 200 yards should be about FOUR times the drift at 100. It the example above, 0.8″ times 4 is 3.2″, pretty darn close to the JBM prediction of 3.3″. Quoting Precision Shooting: “Note that the deflections at 100 yards are typically a quarter of those at 200; lateral deflections increase as the square of the range”. Precision Shooting, June 2000, p. 16.

EXAMPLE TWO — .284 Win (100 to 1000 Yards)
For a .284 Win load, with the slippery Berger 180gr Target Hybrids, the Rule of the Square still works. Here we’ll input a 2750 fps velocity, Litz G7 BC, 10 mph, 9 o’clock crosswind, (same 65° temp at sea level). With these variables, JBM predicts:

Drift at 100: 0.5 MOA (0.5″)
Drift at 500: 2.5 MOA (13.3″)
Drift at 1000: 5.9 MOA (61.3″)

Again, even with a higher BC bullet, at 1000 yards we end up with something reasonably close to the 100-yard deflection (i.e. 0.5″) multiplied by (10×10), i.e. 50 inches. The Rule of the Square alerts you to the fact that the effects of crosswinds are MUCH greater at very long range. In this example, our JBM-calculated drift at 1000 is 61.3″ — that’s over 100 times the 100-yard lateral drift, even though the distance has only increased 10 times.

Note that, even with a 5 mph 90° sidewind, the “Rule of the Square” still applies. The 1000-yard lateral deflection in inches is still over 100 times the lateral deflection at 100 yards.


Why This All Matters (Even in the Age of Smartphones)
wind drift wind reading 6mmbr rule of the squareNow, some would say, “Why Should I Care About the Rule of the Square? My iPhone has a Ballistics App that does all my thinking for me”. Fair enough, but knowledge of this basic Rule of the Square enables a shooter to make an informed guess about necessary windage even without a come-up sheet, as long as he knows the distance AND can fire a sighter at 100 or 200 yards as a baseline.

For example, if I see empirically that I need 1″ windage correction at 100 yards, then I know that at 600 yards I need at least roughly (6 x 6 x 1″) or 36 total inches of drift correction, or 6 MOA. (To be precise, 1 MOA = 1.047″ at 100 yards). I can figure that out instantly, even without a ballistics chart, and even if my Smartphone’s battery is dead.

*Values shown are as displayed on the JBM-figured trajectory tables. The numbers can be slightly imprecise because JBM rounds off to one decimal place for both inches and MOA.

Permalink Shooting Skills, Tech Tip 2 Comments »
January 22nd, 2015

Plug-in Turbine Turns Your Smart Phone into a Wind Meter

weatherflow wind meter anemometer wind gauge turbine smart phone iphone app

Gear Report by Kip Staton
Shooters in the market for an accurate anemometer that doesn’t break the bank need to take a hard look at the WeatherFlow Wind Meter, which retails on Amazon.com for just $34.95. Even though it is inexpensive, owner reviews have been overwhelmingly postive (so long as the software is compatible with your device). One Amazon reviewer says the WeatherFlow measures wind velocity as accurately as his expensive Kestrel.

A big part of the reason the WeatherFlow Wind Meter is so inexpensive is that you’ve probably already got the brains of the system in your pocket. Yes, it connects to and communicates with any standard smartphone or tablet, in either iOS or Android flavors. Users simply download the free WeatherFlow Wind Meter app to their smart device, insert the anemometer into the headphone jack, and can immediately start measuring the wind.

weatherflow wind meter anemometer wind gauge turbine smart phone iphone app

weatherflow wind meter anemometer wind gauge turbine smart phone iphone appOf course, the first question any serious shooter will ask is “How accurate is this thing?” Pretty dang accurate, as it turns out. The device was calibrated by the University of Florida’s Aerospace Engineering Department, and the unique design allows it to consistently report to within a half a percentage point of the true wind value, even if the breeze is up to 15 degrees off-axis to the meter.

Wind speeds are measurable from as slow as two miles per hour to as high as 125 MPH. The Wind Meter outputs average, lull, and gusts windspeed data to your phone, with velocities indicated in 0.1 MPH increments. Furthermore, a hard-sided protective case is included for safe transportation.

Naturally, since the WeatherFlow Wind Meter is App-based, it’s connectable to a variety of social media websites and distribution sources. This makes saving and sharing information about climate conditions a breeze.

About the Writer
Kip Staton is a freelance gun writer based in North Texas, and loves to blog about news within the firearms industry and his perceptions on marksmanship at KipStaton.com. He served as the weekend range manager of the North Texas Shooter’s Association from 2010-2012, at which point he began performing sales consultations for a major online firearms retailer. Currently, Kip is a content marketer, copywriter and digital strategist for an award-winning Dallas marketing agency.

To read more gear reviews by Kip, visit KipStaton.com.

Permalink Gear Review, New Product 3 Comments »
November 6th, 2014

Riding the Wave — Wind-Reading Advice from Mr. Salazar

German Salazar wind readingIn response to questions from a fellow F-Class shooter, German Salazar offered some expert advice in an article entitled: Basics: A Few Wind Reading Tips. Here are highlights from that essay. You can read the entire article on German’s Rifleman’s Journal Website. German cautions that: “I certainly am not attempting to make this short item into a comprehensive lesson in wind reading, but there may be a nugget or two in here for the newer shooter. There is, however, no substitute for range time and coaching.”

Preliminary Matters — Holding Off vs. Knob-Turning
Let’s begin by eliminating one topic altogether — I realize that the predominant method of wind correction in F-Class is holding-off with the crosshairs of your scope rather than adjusting the windage knob. I am a firm believer in aiming at the center and turning the knob as needed, but we’ll leave that for another time and focus on seeing what the wind is doing.

The Wave — Wind Cycles and Shot Timing
I find that most shooters begin to shoot immediately when the time commences rather than waiting for an appropriate moment in the cycle, this often leads to lost points early on. If you’ve been scoring prior to shooting, hopefully you’ve observing the flags and your shooter’s shot placement. It’s a very useful way of gaining some insight into the day’s wind patterns before shooting.

German Salazar wind readingMy technique is based on the understanding of wind as a cyclical wave motion. That statement alone should give you plenty to think about[.] Imagine for a moment, a surfer. He waits for a gentle swell, gets moving on it and rides it through it’s growth and ultimately its crescendo and hopefully avoids being swallowed in its crash. Wind typically behaves in the same fashion as that wave and a smart shooter behaves as does the surfer — get on early in the wave, ride through the major change and get off at the right moment. Knowing when to stop shooting is every bit as important as shooting quickly through the predictable portion of the wave; getting back on to the next wave is a matter of delicate judgment and timing.

When you are on that rising (or falling) wave, the idea is to shoot very quickly to minimize the amount of change between shots and to make a small adjustment on each shot. Too many shooters waste time trying to analyze the exact amount of the change, by which time it has changed even more! Get on with it, click or hold over a set amount and fire the next shot quickly. This is the foundation of how I shoot and it is very effective as long as you know when to start, when to stop and you have a good man working the target – a slow marker is the death of this method.

Watch Shots from Other Shooters
We all watch the wind flags, of course, and the trees if your range is so blessed (ours are fairly barren), and many other small wind indicators. Watching the shots of your fellow shooter can also be a very useful tool and should be observed whenever possible. When a good shooter next to you comes up with a poor shot, it should signal you to stop and reassess conditions as they may not be what they appear.

German Salazar wind reading

While scoring for another shooter, take a moment to scan the line of targets. You’ll be surprised at how most of the shot markers move in unison to one side and then the other. The sad truth is that most shooters are behind the changes in the wind and they will get carried to either side of the bull as the wind changes. You’ll see this in the targets as they come up, and once learned, you’ll find that the line of targets is as useful as another row of flags.

Permalink - Articles, Shooting Skills No Comments »
October 18th, 2014

Video Introduction to Wind-Reading with Sniper’s Hide Boss

Frank Galli (aka “Lowlight”), the head honcho of Sniper’s Hide, has created a good 15-minute wind-reading video for the Scout web network. This video, a segment from the Sniper’s Hide Day One DVD, covers many of the important basics of wind reading. It’s a helpful introduction for those getting started in long-range rifle shooting.

Click Image to Go to Video Playback Page:
lowlight snipers hide wind reading video

Quote 1: “On the range, people describe the wind as the Great Equalizer. Next to your drop, drift from wind is the second most important consideration for the long range precision rifle shooter. Unlike drop, which is predictable, the wind is a constantly changing factor.”

Quote 2: “Wind is like water. It’s important to understand how terrain will effect the wind, how it will change the direction, velocity and consistency. It’s responsible for turbulence, it’s responsible for unseen changes that will throw our shot off. Wind will ebb and flow just like waves crashing on the beach. We need to understand the frequency and velocity of each wave.”

CLICK HERE to Watch Wind-Reading Video.

Permalink - Videos, Tactical 3 Comments »
June 5th, 2014

Windmeter with Rotating Head Shows 90° Crosswind Values

The new-for-2014 Caldwell Crosswind Professional Wind Meter does much more than measure wind velocity. Along with Current Wind Speed, this device will measure and display: Average Wind Speed, Max Wind Gust, Temperature, Station Pressure, Barometric Pressure, Altitude, Density Altitude and even Wind Chill factor. Select among mph, ft/min, km/h, m/s, or knots for the wind speed units.

Caldwell crosswind wind meter

The swiveling impeller head (set parallel to barrel) allows you to determine an interpolated 90° crosswind value to use in your ballistics calculations. This eliminates a lot of guesswork.

You might say, “Why do I need a rotating head, I can just turn the whole wind meter to align the impeller axis with the wind?” Yes you can, but then you merely get a raw speed value, and you have to guesstimate the wind angle, and then calculate your actual windage correction based on the vector.

The rotating impeller ring on the Caldwell simplifies the job of calculating windage. The swivel head is designed to show an effective 90-degree crosswind value, no matter what the actual wind direction. Here’s how it works. Hold the unit with the display screen facing you. Then rotate the impeller head until it aligns with the barrel axis (bullet line of flight). The plastic shell surrounding the impeller is specifically designed so that the blades will spin faster or slower depending on the true wind angle. This allows the unit to estimate the effective 90-degree crosswind value (for your ballistics program). Pretty clever eh? See diagram to understand how this works:

Caldwell crosswind wind meter

This unit comes complete with rotating anemometer head, protective holster case, and one CR2032 battery. The unit has an auto “Power-Off” feature to preserve battery life. There is also a “Data Hold” function plus an LCD Backlight. NOTE: When figuring effective 90° crosswind values, Caldwell recommends using Average Wind Speed mode rather than Current Wind Speed.

Caldwell crosswind wind meter

Permalink Gear Review, New Product 2 Comments »
April 26th, 2014

Praslick Teaches Wind-Reading Skills

Emil Praslick USAMUTo succeed in long-range shooting matches, given the high level of competition these days, you’ll need solid wind-reading abilities. We’ve found an article by SFC Emil Praslick III, USAMU Service Rifle coach, that can help you make better wind calls in competition.

SFC Praslick is considered one of the best wind gurus in the United States, if not the world. He has authored an excellent two-part article on wind reading that is available on the CMP (Civilian Marksmanship Program) website. Both articles contain helpful illustrations, and are “must-read” resources for any long-range shooter–not just Service Rifle and Highpower competitors.

Click to Read Articles:

Reading the Wind (Part One) | Reading the Wind (Part Two)

Part One covers basic principles, tactics, and strategies, with a focus on the 200-yard stages. Emil writes: “There are as many dimensions to ‘wind reading’ as there are stages to High Power competition. Your tactical mindset, or philosophy, must be different for the 200 and 300 yard rapid-fire stages than it would be for the 600 yard slow-fire. In the slow-fire stages you have the ability to adjust windage from shot to shot, utilizing the location of the previous shot as an indicator. Additionally, a change to the existing conditions can be identified and adjusted for prior to shooting the next shot.”

In Part Two, Praslick provides more detailed explanations of the key principles of wind zeros, wind reading, and the “Clock System” for determining wind values: “The Value of the wind is as important as its speed when deciding the proper windage to place on the rifle. A 10 MPH wind from ’12 o-clock’ has No Value, hence it will not effect the flight of the bullet. A 10 MPH wind from ‘3 o’clock’, however, would be classified as Full Value. Failure to correct for a Full Value wind will surely result in a less than desirable result.”

USAMU Praslick wind clock

Praslick also explains how to identify and evaluate mirage:

Determine the accuracy of the mirage. Mirage is the reflection of light through layers of air that have different temperatures than the ground. These layers are blown by the wind and can be monitored to detect wind direction and speed.

Focus your scope midway between yourself and the target, this will make mirage appear more prominent. I must emphasize the importance of experience when using mirage as a wind-reading tool. The best way to become proficient in the use of mirage is to correlate its appearance to a known condition. Using this as a baseline, changes in mirage can be equated to changes in the value of the wind. Above all, you must practice this skill!

Click HERE for more excellent instructional articles by Emil Praslick and other USAMU Coaches and shooters.

Permalink - Articles, Shooting Skills 4 Comments »
October 10th, 2013

Wind Box Shelters Scales When Reloading at Outdoor Ranges

Shooters who reload at the range, during the course of benchrest matches, or during load development sessions, can benefit from having a portable scale to weigh charges. Even if you throw charges, using click values, a scale allows you to double-check the accuracy of your throws. In addition, having a scale handy lets you weigh and sort components during load development.

Many reloaders prefer “old-fashioned” balance beam scales for range use. They are relatively inexpensive and simple to use. With a beam scale, unlike electronic scales, you don’t have to worry about weak batteries or finding AC power. The problem when using any scale at an outdoor range is wind. Wind can cause powder to blow out of the pan and even a light breeze can actually cause a beam scale to perform erratically.

Beat the Breezes with a Wind Box for your Scale
Forum member Boyd Allen has come up with a smart solution for reloaders who use scales outdoors — a windproof scale enclosure, aka “Wind Box”. This is something that can easily be built at home with common tools. Boyd explains: “Many guys have good set-ups for loading at the range, with clamping mounts for powder measure and press. But they lack a good enclosure for a scale. This is vitally important with beam scales because they have a lot of surface area to catch the wind. With much wind at all, the beam can oscillate to the point that is not really very usable. While a low-profile electronic scale may be less wind-sensitive, breezes DO affect weight read-outs on digital scales. And of course you always have the issue of blowing powder particles.”

Wind box range reloading

Boyd Allen has used his Wind Box successfully for many seasons. He explains: “Some time ago, I got this idea, and was fortunate enough to have a friend, Ed Hellam, who liked the idea well enough to build us both one. He did a fine job, but since this was the prototype there was at least one lesson to learn. The original viewing pane was Plexiglass, and I discovered that it would hold enough static charge to throw the scale off 0.1 grains, so another friend, Bob Smith, modified my Wind Box, replacing the Plexiglass with a tempered glass faceplate. Thank you Ed and Bob….

The essence of the idea is to have a scale set up in a box with a clear cover that can be opened and closed. On one side the trickler handle/control emerges through a ‘just big enough’ hole. You raise the cover, add a sub-target-weight thrown charge to the pan, and then close the cover. With the cover secure, the set-up is protected from the wind, and you can now trickle up to your desired charge. It works very well. The scale in the photo is an old Ohaus that I picked up. It is actually more sensitive than my RCBS 10-10 and works fine. You can adapt this Wind Box design to any beam scale, or portable electronic scale. Simply adjust the dimensions to fit your particular scale and trickler.”

Wind box range reloading

Permalink Gear Review, New Product No Comments »
July 22nd, 2013

Great Article on Reading Mirage

South Texas marksmanship trainingThere is an excellent article about Mirage on the South Texas Marksmanship Training Center (STMTC) website. This article explains what causes mirage and how mirage can move the perceived aiming point on your target. Most importantly, the article explains, in considerable detail, how you can “read” mirage to discern wind speeds and wind directions. With simple but effective graphic illustrations, this is one of the best explanations of mirage (and mirage reading) we have found on the internet. This is a “must-read” for any serious competitive shooter. Here is a brief sample from the article, along with an illustration. NOTE: the full article is six times longer and has 8 diagrams.

The term “mirage” as used by the shooter does not refer to a true mirage, but to heat waves and the refraction of light as it is bent passing through air layers of different density. Light which passes obliquely from one wind medium to another it undergoes an abrupt change in direction, whenever its velocity in the second medium is different from the velocity in the first wind medium; the shooter will see a “mirage”.

The density of air, and therefore its refraction, varies with its temperature. A condition of cool air overlaying warm air next to the ground is the cause of heat waves or “mirage”. The warm air, having a lower index of refraction, is mixed with the cooler air above by convection, irregularly bending the light transmitting the target image to the shooter’s eye. Figure 1 shows (greatly exaggerated) the vertical displacement of the target image by heat waves.

South Texas Mirage Reading article

Heat waves are easily seen with the unaided eye on a hot, bright day and can be seen with spotting scope on all but the coldest days. To observe heat waves, the scope should be focused on a point about midway to the target. This will cause the target to appear slightly out of focus, but since the high power rifle shooter generally does not try to spot bullet holes, the lack in target clarity is more than compensated by clarity of the heat waves.

CLICK HERE to Read Complete Mirage Article

Mirage Is Your Friend
While hot days with lots of mirage can be frustrating, mirage can reveal how the wind is flowing (and changing). If you learn how to recognize and read mirage patterns, you can use that information to shoot higher scores. That’s why many leading long-range shooters tell us: “Mirage is your friend.” As the STMTC article explains: “A mirage condition is not a handicap, since it offers a very accurate method of perceiving small wind changes[.]”

Story tip from Boyd Allen. We welcome reader submissions.
Permalink - Articles, Competition 3 Comments »
May 29th, 2012

Wind-Reading LaserScope Patented by Israeli Nuke Lab

Imagine a “smart scope” that can range your target AND calculate windage correction. Such technology may appear in riflescopes fairly soon. The Israeli Government’s Soreq Nuclear Research Center has received a U.S. patent for a new laser-based technology that can gauge wind vectors as well as target distance, using a laser rangefinder coupled to a rifle-scope. The Israeli system is called LIDAR, an acronym for Laser Identification Detection And Ranging. This new technology could, potentially, be a major boon for long-range shooters, both military and civilian. Ironically LIDAR was first developed for environmental monitoring (not for use with weapons). A LIDAR system was used for 3-D mapping and modeling of wind-driven plumes from the Israel Electric Company’s Rabin power plant.

Credit The Firearm Blog for breaking this story on the new Israeli LIDAR technology for sniper scopes. Below you’ll find the LIDAR Patent Application Abstract, which has a good summary of how LIDAR reads the wind.

The new Israeli LIDAR unit gauges wind speed by detecting fluctations in laser signals sent out from the integrated scope/LRF, reflected back from the target, and then received by photodiodes in the scope/LRF. Other scopes have used built-in LRFs to measure distance-to-target, but Israel’s patented LIDAR goes one step further, using the laser to gauge BOTH target distance AND wind vectors (i.e. velocity + direction). This information is entered automatically into software. The software then calculates a ballistic solution compensating for distance, wind angle, and wind velocity. If it really works, LIDAR represents a remarkable technological achievement. The Israelis claim LIDAR works for targets at distances of 500m or greater. Why won’t it work at closer ranges? Presumably the wind-induced laser fluctuations are too small to register at closer distances.

Current Integrated LaserScopes for Hunters
While the Israeli LIDAR system may seem like science fiction, it’s not that far removed from the lastest commercial optics. Engineers on both sides of the Atlantic have already integrated laser rangefinders (LRFs) into rifle-mounted “consumer” optics. Just this year, Burris introduced an affordable “consumer” scope, the Eliminator, that ranges the distance to target and then displays the ballistically correct aiming point on the vertical crosshair. The amount of hold-over is automatically calculated with reference to ballistics formulas. At right is a view through the Burris Eliminator; the illuminated dot shows the calculated aiming point.

While such technology can help a shooter compensate for bullet drop, windage compensation is another matter. A shooter must still gauge crosswind angle and velocity, and then hold left or right accordingly. If the LIDAR system can perform this task reliably, that is a major advancement.

DARPA “One Shot” System to Have Wind-Reading Capability
Meanwhile, in the United States, the Defense Advanced Research Projects Agency (DARPA) is proceeding forward with a One-Shot Sniper System, another “Super-Scope” that will have day/night capability, and calculate both elevation AND windage correction automatically. Prototypes have already been tested, demonstrating that a laser beam can be used to “measure the average down-range crosswind profile”. The wind data is combined with readings of temperature, humidity, and target range to provide a very sophisticated ballistic solution. DARPA’s Spec for the One Shot program calls for a 12-42X Direct View Optic (DVO), a Riflescope Display Assembly (RDA), and an Integrated Spotting Scope (ISS) with rangefinder that ranges to 2 km, and provides “crosswind measurements”. The system will be “menu-selectable” for .308 Win, .338 Lapua, and .300 Win Mag. DARPA has budgeted big bucks for the One Shot system. The ISS, by itself, is expected to cost $85,000 per unit (for the first 15 units).

These systems will never replace the utility of an experienced shooter who possesses the skills of wind reading, but it is a real boon for less experienced shooters. In terms of military utility, it is a game changer. I’ve seen and used a prototype of the One Shot, and it does perform as advertised. — SFC Emil Praslick III, USAMU Coach

Can Wind-Reading Systems Work in the Real World?
From what we can tell, the LIDAR system, and America’s competing One Shot System, are both designed to measure crosswind speed and angle AT THE TARGET primarily. But as any experienced long-range shooter knows, wind is rarely constant along the entire path of the bullet. There can be a 10 mph left wind near the firing point, a 5 mph tailwind in mid-trajectory, and a 20 mph right wind 1000 yards away. Importantly, wind close to the shooter has more effect on the bullet’s path than wind far downrange — that’s a matter of simple geometry. Therefore, any wind-reading system could provide incorrect solutions if it is not able to read and calculate different wind vectors along the full bullet flight path. Presumably LIDAR and One Shot systems will attempt some kind of crosswind averaging, but that will be a very challenging task, without multiple wind sensors downrange.

Permalink New Product, Optics 6 Comments »
January 3rd, 2012

Kenton Offers Custom-Calibrated Windage and Elevation Knobs

Kenton Calibrated Windage KnobHere’s something that can save you lots of time and aggravation on a varminting trip. This little $110 gizmo is great for varmint hunters and any one who needs to make a quick shot in shifty wind conditions. Instead of the traditional 1/4-MOA hash marks, the Kenton windage turret features markers corresponding to the wind drift your ammo will encounter at various distances (with 10 mph full value winds). You just dial the distance.

Custom-Calibrated Windage Knobs
Kenton Industries’ Tuned Windage Compensator (TWC) has built-in windage marks for 10 mph cross-winds at 100-1000 yards. How do they do that? Well the knobs are calibrated either for specific calibers/loads, or they can make custom knobs using your observed field data. The knobs can compensate for various wind speeds (2-20 mph) and angles (15°- 90°), by applying some simple conversion ratios. As a general rule, with a “full-value”, i.e. 90°, crosswind, the wind drift will go up or down in direct proportion to the change in windspeed. That means, for example, a 10 mph crosswind will push the bullet twice as much sideways as a 5 mph crosswind.

Two versions of Kenton’s TWC knobs are offered. The $109.95 TWC #1 features calculated ballistics for standardized factory ammo for the caliber and barrel length you specify. The $109.95 TWC #2 feature customized windage settings based on bullet BC, environmental conditions, elevation, and ballistic information you provide.

Custom Elevation Knobs
Kenton also makes a $109.95 elevation-compensating TTC knob, that can be customized to your rifle. With this elevation turret, yardages are marked in 50-yard increments, and you can literally just “dial in your distance”. However, to work effectively the TTC knob must be tailored to a particular load (velocity and bullet). Moreover, actual bullet drop will differ with changes in altitude, temperature, and shooting angle — so it’s not as simple as it sounds, and you may need multiple knobs if you shoot a variety of loads. Kenton offers it TTC #1 model calibrated for standardized factory ammo. The TTC #2 is calibrated out to the maximum effective range of your cartridge based on bullet type, muzzle velocity, altitude, and temperature. Select the type of yardage format to be used. The #2 is recommended for wildcatters or for those who want to adjust to specific conditions. Lastly, a TTC #3 elevation knob is offered that relies on the purchaser’s actual recorded drop data from the field. The TTC #3 elevation knob will be calibrated based on the click-value or MOA you provide for each 50-yard increment.

Permalink Gear Review, Hunting/Varminting, Optics 2 Comments »