Emil Praslick III is widely recognized as one of the greatest wind wizards on the planet — a master at identifying wind value and direction, and predicting wind cycles. As coach of the USAMU and top civilian teams, Emil has helped win many high-level championships. In the three videos we feature today, Emil, who works with Capstone Precision Group (Berger, Lapua, SK, Vihtavuori) and Team Applied Ballistics, explains how to determine wind direction and velocity using a variety of indicators. Praslick, now retired from the U.S. Army, was an 18-time National and 2-time World Champion coach with the USAMU.
Video ONE: Wind Theory Basics — Understanding “Wind Values”
In this video from UltimateReloader.com, Emil explains the basics of modern wind theory. To properly understand the effect of the wind you need to know both the velocity of the wind and its angle. The combination of those variables translates to the wind value. Emil also explains that the wind value may not be constant — it can cycle both in speed and velocity. Emil also explains some of the environmental conditions such as mirage that can reveal wind conditions.
Video TWO: Determining the Direction of the Wind
Key Point in Video — Find the Boil
Emil explains how to determine wind direction using optic. The method is to use spotting scope, riflescope, or binoculars to look for the “Boil” — the condition in mirage when the light waves rising straight up. The wind will generate that straight-up, vertical boil in your optics when it is blowing directly at you, or directly from your rear. To identify this, traverse your scope or optics until you see the boil running straight up. When you see that vertical boil, the direction your optic is pointing is aligned with the wind flow (either blowing towards you or from directly behind you).
Video THREE: The No Wind Zero Setting
In this second video, Emil defines the “No-Wind Zero”, and explains why competitive shooters must understand the no-wind zero and have their sights or optics set for a no-wind zero starting point before heading to a match. In order to hit your target, after determining wind speed and direction, says Emil, “you have to have your scope setting dialed to ‘no wind zero’ first.”
Coach of Champions — Emil Praslick III
SFC Emil Praslick III, (U.S. Army, retired) works with Berger Bullets and Applied Ballistics. Emil served as the Head Coach of the U.S. National Long Range Rifle Team and Head Coach of the USAMU for several years. Teams coached by Emil have won 33 Inter-Service Rifle Championships. On top of that, teams he coached set 18 National records and 2 World Records. Overall, in the role of coach, Praslick can be credited with the most team wins of any coach in U.S. Military history.
The 2026 Southwest Nationals (SWN) start today, 2/11/2026, at the Ben Avery Range outside Phoenix, AZ. The big event starts with a 600-yard Mid-Range Match. Many of the nation’s most talented F-Class and sling shooters will be there. But no matter what your skill level, it is still possible to make major mistakes that can spoil the day and/or put you out of the running for the entire match. This article aims to help competitors avoid the big errors/oversights/failures, aka “train wrecks”, that can ruin a match.
Photo by Sherri Jo Gallagher.
In any shooting competition, you must try to avoid major screw-ups that can ruin your day (or your match). In this article, past F-TR National Mid-Range and Long Range Champion Bryan Litz talks about “Train Wrecks”, i.e. those big disasters (such as equipment failures) that can ruin a whole match. Bryan illustrates the types of “train wrecks” that commonly befall competitors, and he explains how to avoid these “unmitigated disasters”.
Urban Dictionary “Train Wreck” Definition: “A total @#$&! disaster … the kind that makes you want to shake your head.”
Success in long range competition depends on many things. Those who aspire to be competitive are usually detail-oriented, and focused on all the small things that might give them an edge. Unfortunately it’s common for shooters lose sight of the big picture — missing the forest for the trees, so to speak.
Consistency is one of the universal principles of successful shooting. The tournament champion is the shooter with the highest average performance over several days, often times not winning a single match. While you can win tournaments without an isolated stellar performance, you cannot win tournaments if you have a single train wreck performance. And this is why it’s important for the detail-oriented shooter to keep an eye out for potential “big picture” problems that can derail the train of success!
Train wrecks can be defined differently by shooters of various skill levels and categories. Anything from problems causing a miss, to problems causing a 3/4-MOA shift in wind zero can manifest as a train wreck, depending on the kind of shooting you’re doing.
Below is a list of common Shooting Match Train Wrecks, and suggestions for avoiding them.
1. Cross-Firing. The fastest and most common way to destroy your score (and any hopes of winning a tournament) is to cross-fire. The cure is obviously basic awareness of your target number on each shot, but you can stack the odds in your favor if you’re smart. For sling shooters, establish your Natural Point of Aim (NPA) and monitor that it doesn’t shift during your course of fire. If you’re doing this right, you’ll always come back on your target naturally, without deliberately checking each time. You should be doing this anyway, but avoiding cross-fires is another incentive for monitoring this important fundamental. In F-Class shooting, pay attention to how the rifle recoils, and where the crosshairs settle. If the crosshairs always settle to the right, either make an adjustment to your bipod, hold, or simply make sure to move back each shot. Also consider your scope. Running super high magnification can leave the number board out of the scope’s field view. That can really increase the risk of cross-firing.
2. Equipment Failure. There are a wide variety of equipment failures you may encounter at a match, from loose sight fasteners, to broken bipods, to high-round-count barrels that that suddenly “go south” (just to mention a few possibilities). Mechanical components can and do fail. The best policy is to put some thought into what the critical failure points are, monitor wear of these parts, and have spares ready. This is where an ounce of prevention can prevent a ton of train wreck. On this note, if you like running hot loads, consider whether that extra 20 fps is worth blowing up a bullet (10 points), sticking a bolt (DNF), or worse yet, causing injury to yourself or someone nearby.
3. Scoring/Pit Malfunction. Although not related to your shooting technique, doing things to insure you get at least fair treatment from your scorer and pit puller is a good idea. Try to meet the others on your target so they can associate a face with the shooter for whom they’re pulling. If you learn your scorer is a Democrat, it’s probably best not to tell Obama jokes before you go for record. If your pit puller is elderly, it may be unwise to shoot very rapidly and risk a shot being missed (by the pit worker), or having to call for a mark. Slowing down a second or two between shots might prevent a 5-minute delay and possibly an undeserved miss.
Photo by Sherri Jo Gallagher.
4. Wind Issues. Tricky winds derail many trains. A lot can be written about wind strategies, but here’s a simple tip about how to take the edge off a worse case scenario. You don’t have to start blazing away on the command of “Commence fire”. If the wind is blowing like a bastard when your time starts, just wait! You’re allotted 30 minutes to fire your string in long range slow fire. With average pit service, it might take you 10 minutes if you hustle, less in F-Class. Point being, you have about three times longer than you need. So let everyone else shoot through the storm and look for a window (or windows) of time which are not so adverse. Of course this is a risk, conditions might get worse if you wait. This is where judgment comes in. Just know you have options for managing time and keep an eye on the clock. Saving rounds in a slow fire match is a costly and embarrassing train wreck.
5. Mind Your Physical Health. While traveling for shooting matches, most shooters break their normal patterns of diet, sleep, alcohol consumption, etc. These disruptions to the norm can have detrimental effects on your body and your ability to shoot and even think clearly. If you’re used to an indoor job and eating salads in air-conditioned break rooms and you travel to a week-long rifle match which keeps you on your feet all day in 90-degree heat and high humidity, while eating greasy restaurant food, drinking beer and getting little sleep, then you might as well plan on daily train wrecks. If the match is four hours away, rather than leaving at 3:00 am and drinking five cups of coffee on the morning drive, arrive the night before and get a good night’s sleep.”
Keep focused on the important stuff. You never want to lose sight of the big picture. Keep the important, common sense things in mind as well as the minutia of meplat trimming, weighing powder to the kernel, and cleaning your barrel ’til it’s squeaky clean. Remember, all the little enhancements can’t make up for one big train wreck!
Here’s a smart tip from Bryan Litz, explaining how damage to a bullet jacket can harm the projectile’s Ballistic Coefficient (BC). This tip is posted on Bryan’s new Bryan Litz Ballistics Facebook page. We recommend you subscribe to that page to access Bryan’s latest informative posts.
Bryan notes: “If the case mouth scratches the bullet when you seat it, the damage can cause the BC to be inconsistent, which shows up as vertical dispersion at long range.”
We see this sometimes when running Doppler Radar for competitors at Applied Ballistics Mobile Lab events. If someone is shooting a bullet that typically has a very consistent BC (1% or less) but they’re seeing a higher BC variation, it can be due to the bullets being damaged in the loading process.”
The lead photo above shows the badly-scratched jacket of a bullet seated in a rough-mouthed case. To prevent such jacket damage, one should chamfer, deburr, and smooth case mouths after trimming.
Below is a recorded Doppler radar result showing excessive BC variation. Such variation can increase vertical dispersion at long range. This can result in larger group sizes and lower scores.
Q: What’s more important — wind speed, or direction?
A: Obviously they both matter, but they do trade dominance based on direction. For example, a 10 mph wind between 2:30 and 3:30 is only changing its value from 9.7 to 10 to 9.7 mph (bracket of 0.3 mph). However a 10 mph wind between 11:30 and 12:30 is changing its cross wind component value from 2.6 mph left to zero to 2.6 mph right (bracket of 5.2 mph). There is the same 30° change in direction, but this results in a massively different bracket.
Point being, in this case, a direction change is far more critical if it’s near 6 or 12 o’clock. A small direction change when it’s close to 3 or 9 o’clock is negligible.
On the contrary, a change in wind SPEED when it’s near 3 or 9 affects your crosswind component directly. But for a near head or tail wind, a fluctuation in wind speed only causes a small fraction of a change to the crosswind component.
SUMMARY: If you’re in a near full-value wind, pay more attention to wind SPEED. If you’re closer to a head- or tail-wind, nailing the exact DIRECTION will be more important.
Get More Tips on Bryan Litz Ballistics Facebook Page
This post is from the new Bryan Litz Ballistics Facebook Page. FB users should check that page regularly for more tips from Bryan, American’s leading ballistics expert and founder of Applied Ballistics LLC.
Berger Twist-Rate Stability Calculator
On the Berger Bullets website you’ll find a handy Twist-Rate Stability Calculator that predicts your gyroscopic stability factor (SG) based on mulitiple variables: velocity, bullet length, bullet weight, barrel twist rate, ambient temperature, and altitude. This cool tool tells you if your chosen bullet will really stabilize in your barrel.
How to Use Berger’s Twist Rate Calculator
Using the Twist Rate Calculator is simple. Just enter the bullet DIAMETER (e.g. .264), bullet WEIGHT (in grains), and bullet overall LENGTH (in inches). On its website, Berger conveniently provides this info for all its bullet types. For other brands, we suggest you weigh three examples of your chosen bullet, and also measure the length on three samples. Then use the average weight and length of the three. To calculate bullet stability, simply enter your bullet data (along with observed Muzzle Velocity, outside Temperature, and Altitude) and click “Calculate SG”. Try different twist rate numbers (and recalculate) until you get an SG value of 1.4 (or higher).
Gyroscopic Stability (SG) and Twist Rate
Berger’s Twist Rate Calculator provides a predicted stability value called “SG” (for “Gyroscopic Stability”). This indicates the Gyroscopic Stability applied to the bullet by spin. This number is derived from the basic equation: SG = (rigidity of the spinning mass)/(overturning aerodynamic torque).
If you have an SG under 1.0, your bullet is predicted not to stabilize. If you have between 1.0 and 1.1 SG, your bullet may or may not stabilize. If you have an SG greater than 1.1, your bullet should stabilize under optimal conditions, but stabilization might not be adequate when temperature, altitude, or other variables are less-than-optimal. That’s why Berger normally recommends at least 1.5 SG to get out of the “Marginal Stability” zone.
In his book Applied Ballistics For Long-Range Shooting, 3rd Ed., Bryan Litz (Berger Ballistician) recommends at least a 1.4 SG rating when selecting a barrel twist for a particular bullet. This gives you a safety margin for shooting under various conditions, such as higher or lower altitudes or temperatures.
Story idea from EdLongrange. We welcome reader submissions.
Photo shows Bryan Litz (on right) and tester Mitchell Fitzpatrick. Bryan said: “Only 2,445 rounds to go! We’re testing over 50 ammo types in five different twist barrels… science can be exhausting!”
Do you know the actual BC (Ballistic Coefficient) of your rimfire ammunition? Well Applied Ballistics has the data, thanks to a comprehensive, marathon ammo testing session. Some years back, in an effort to determine the “real world” BCs of various rimfire ammo types, Bryan Litz and his team at Applied Ballistics did an extraordinary, in-depth shooting test. Litz and company tested over fifty types of .22 LR ammo, using five different twist-rate barrels. This was one of the most comprehensive and through rimfire ammo tests ever done.
Bryan tolds us: “We tested many types of .22 rimfire ammo for the 2nd Edition of the Ballistic Performance of Rifle Bullets book. We used a pair of Oehler chronographs to measure velocity at the muzzle (MV) and velocity at 100 yards.” With these numbers (average and SD) Bryan can calculate G1 BCs for all the 50+ types of rimfire ammo. What’s more, because every sample is shot through five different barrels (each with a different twist rate) Bryan can also determine how velocity is affected by twist rate.
The tests are primarily to determine velocities for BC calculations — this was not an accuracy test. Bryan explains: “Our tests are not really looking at accuracy, mainly because that’s so subjective to different rifles. Our testing is primarily focused on measuring the BC of rimfire rounds from different twist-rate barrels. The MVs and BCs from the different twist test barrels was then published by Applied Ballistics in print books. Bryan Litz told us: “The .22 LR Rimfire data was originally published in Ballistic Performance of Rifle Bullets, 2nd Edition, which is now out of print. The 3rd Edition of that book doesn’t have rimfire data. The rimfire testing results and data were re-published in Modern Advancements in Long Range Shooting – Volume II (along with many other topics).
Bringing Science to the Rimfire World
Bryan’s goal with this project was to increase the rimfire knowledge base: “We hope to give the world of .22 LR rimfire a good dose of science. How is the BC of .22 rimfire ammo affected by barrel twist? Do subsonic rounds have more consistent BCs than supersonic or transonic rounds? What brands have the highest BCs? What brands have the most consistent MVs?”
Data from two Oehler chronographs is recorded in a computer. Ammo samples were tested in five (5) different barrels (of varying twist rates). Give credit to Dane Hobbs who supplied a test rifle, multiple barrels, and most of the ammo types for the test.
.22 LR at 300 Yards?
Bryan also conducted some longer range rimfire tests. His interesting findings have appeared in the Modern Advancements in Long Range Shooting book series. Bryan notes: “While .22 rimfire isn’t typically considered ‘long range’, we were able to consistently hit a two-MOA steel target at 300 yards with the trajectory predicted by AB software and the measured BC of some standard .22 LR rimfire ammo. The info we’’re generating may make it possible to push the range of target engagement for a round that’s not seen much advancement in many decades.”
Christmas is less than three weeks away. If you are looking for a great gift for a shooting buddy, books have always been popular holiday gifts. Here are some recommended titles that should please the serious shooters and firearms enthusiasts on your shopping list. For shooting clubs, books also make great end-of-season member awards. Most of us would rather have a useful book than one more piece of wood to toss in a box in the closet. Check out these ten titles — for yourself or your shooting buddies.
Here Are TEN Great BOOKS Recommended for Serious Shooters:
If you’re a serious long-range shooter, consider adding this book to your library. Relying on extensive ballistics testing, Modern Advancements, Volume II is a great successor to Volume I that contains some fascinating research results. UK gun writer Laurie Holland notes: “Volume II of the Modern Advancements series is as fascinating as Volume I and if anything even more valuable given a series of ‘mythbusters’ tests including: case fill-ratio, primer flash-hole uniforming, neck tension, annealing, and much more. The work also addresses that perennial discussion of a bullet ‘going to sleep’ and shooting smaller groups (in MOA) at longer distances than 100 yards.” The amount of testing done for this Volume II work, with a staggering amount of rounds sent downrange, makes this book unique among shooting resources. There is a ton of “hard science” in this book — not just opinions.
Nancy Tompkins is one of the greatest long-range shooters in American history. She has won five National Long-range Championships. Tompkins’ treatise is a must-read for serious Palma, F-Class, and High Power shooters. The revised Second edition includes F-Class equipment and techniques, and newly updated information. Color pictures. Topics include Mental & Physical training, Reading Wind & Mirage Shooting Fundamentals, International Competition, and Loading for Long Range. Nancy Tompkins is a 4-time winner of the National Long Range Championships, and has won countless other major events. Nancy has been on six Palma Teams (as both a shooter and a coach).
The lastest edition of The Wind Book was released in 2020. The updates make this very helpful 144-page book even better. The Wind Book for Rifle Shooters by Linda Miller and Keith Cunningham, first published in 2007, is a very informative resource. But you don’t have to take our word for it. If you click this link, you can read book excerpts on Amazon.com. This lets you preview the first few chapters, and see some illustrations. Other books cover wind reading in a broader discussion of ballistics or long-range shooting. But the Miller & Cunningham book is ALL about wind reading from cover to cover, and that is its strength. The book focuses on real world skills that can help you accurately gauge wind angle, wind velocity, and wind cycles. Readers have praised the book, earning it 93% 4- and 5-star reviews on Amazon.
Ryan Cleckner is noted for his ability to explain complex topics in an easy-to-comprehend manner. Now Cleckner has authored a book, the Long Range Shooting Handbook, which expands on the topics covered in Cleckner’s popular NSSF video series. The Long Range Shooting Handbook is divided into three main categories: What It Is/How It Works, Fundamentals, and How to Use It. “What It Is/How It Works” covers equipment, terminology, and basic principles. “Fundamentals” covers the theory of long range shooting. “How to Use It” gives practical advice on implementing what you’ve learned, so you can progress as a skilled, long range shooter. You can view Sample Chapters from Ryan’s Book on Amazon.com.
Visualization is a process of mental preparation that is done before you get to the range. Many of the greatest shooting champions have used this technique to get ready for big matches, and to optimize their performance during record fire. If you want to enhance your “mental game” through pre-match visualization, we strongly recommend Lanny Bassham’s book, With Winning in Mind. As a competitive smallbore 3P shooter, Bassham developed a mental management system. Using this system, Lanny Bassham won 22 world individual and team titles, set four world records, and captured an Olympic Gold Medal in Montreal in 1976. His techniques have been embraced by professional and Olympic athletes in many sports. With Winning in Mind covers a complete system of “mental management” techniques used by Olympians and elite champions.
Thinking of getting started in the Practical/Tactical shooting game? Looking for ways to be more stable when shooting from unconventional positions? Then you may want to read Marcus Blanchard’s Practical Shooter’s Guide (A How-To Approach for Unconventional Firing Positions and Training). Unlike almost every “how to shoot” book on the market, Blanchard’s work focuses on the shooting skills and positions you need to succeed in PRS matches and similar tactical competitions. Blanchard provides clear advice on shooting from barricades, from roof-tops, from steep angles. Blanchard says you need to train for these types of challenges: “I believe the largest factor in the improvement of the average shooter isn’t necessarily the gear; it’s the way the shooter approaches obstacles and how they properly train for them.”
The Rifle Shooter by G. David Tubb, $34.95 (Softcover) — $5.00 on Sale
This book by 11-time National High Power Champion David Tubb focuses on position shooting and High Power disciplines. Section One covers fundamentals: position points, natural point of aim, breathing, triggering mechanics and follow-through, sling selection and use, getting started, getting better, avoiding obstacles. Section Two covers mechanics of offhand, sitting, and prone positions. Section Three covers shooting skills, including wind reading and mental preparation. Section Four covers the technical side of shooting, with extensive discussions of rifle design, load development, reloading barrel maintenance, and rifle fitting. We consider this book a “must-read” for any sling shooter, and there is plenty of good advice for F-Class shooters too.
Another fine book for PRS/NRL shooting is Precision Rifle Marksmanship: The Fundamentals by Frank Galli, founder of SnipersHide.com. Former USMC scout-sniper Frank Galli explains techniques will benefit any PRS/NRL competitor. Along with position shooting tips, Galli offers great wind-reading advice. Published in 2020, Galli’s treatise is four years newer than Blanchard’s book, so it includes more of the latest gear and equipment. Galli’s book covers the fundamentals of precision marksmanship with easy-to-understand methodology. The book follows the same instruction process Galli uses in his live marksmanship classes. Published in 2020, this well-illustrated, 272-page book covers the latest equipment (scopes, LRFs, chassis systems, magazines, bags, bipods, tripods) favored by tactical competitors in PRS/NRL type matches.
Tony Boyer, the most successful shooter in the history of short-range benchrest competition, shares match-winning tips in this 323-page book. The book covers all aspect of the benchrest discipline: loading, windflags, rest set-up, addressing the rifle, and match strategies. This is a high-quality publication, filled with valuable insights. Every serious benchrest shooter should read Tony’s book. Boyer has dominated registered benchrest in a fashion that will never be duplicated, having amassed 142 U.S. Benchrest Hall of Fame points. The next closest shooter, Allie Euber, has 47 Hall of Fame points. This handsome, full-color book is 323 pages long, with color photos or color illustrations on nearly every page.
Cartridges of the World (17th Edition), belongs in every serious gun guy’s library. This massive 704-page reference, the most complete cartridge reference guide in print, contains illustrations and basic load data for over 1500 cartridges. If you load for a wide variety of cartridges, or are a cartridge collector, this book is a “must-have” resource. The latest 2022 edition includes dozens of new cartridges and boasts 1500+ photos. The 17th Edition of Cartridges of the World includes cartridge specs, plus tech articles on Cartridge identification, SAAMI guidelines, wildcatting, and new cartridge design trends. Cartridges of the World now includes a full-color section with feature articles.
On the Applied Ballistics Facebook Page, there was a fascinating series of posts showing traces of bullets at various speeds from Mach 0.86 to Mach 3.0. At the slowest speed, Mach 0.86, i.e. 962 FPS, there is turbulence behind the bullet, but no clear shockwave. At the highest velocity, Mach 3.0 (3375 FPS at sea level, 68° F), there is a dramatic double nose and tail wave formation.
To learn more, visit TheScienceofAccuracy.com. On that site you’ll find exclusive video content and you can subscribe to member’s only Podcasts. And you can purchase Applied Ballistics books on the Science of Accuracy webstore.
Mach 3.00 Bullet Flight Image
At Mach 3 (3355 FPS) this bullet now has a strong and well established shock wave forming at the tip, and at the base. Unlike the transition through Mach 1.0, nothing really interesting happens to the aerodynamics or shock waves meaning the aerodynamics and stability are: continuous, easy to predict, and model. As you go faster, the shockwaves make a shallower angle because the bullet is moving forward 3X faster than the shock wave is moving away from it. So the shock wave makes an angle that has a rise/run ratio of 1/3.
If a bullet flew within 10 feet of you traveling this fast, it would be about as loud as a 22 magnum. You’d certainly want hearing protection as the energy contained in a Mach 3 shock wave is high! How high…? Well, in 10 yards, this bullet slows from 3355 FPS to 3334 FPS in a time of 0.0090 seconds. The 55 ft-lb of kinetic energy lost during this 10 yards is due to aerodynamic drag on the bullet, which is comprised of wave, base, and skin friction drag components with the majority of the drag being due to shock wave formation. Expending 55 ft-lb of energy in 0.0090 seconds requires a power output of 6111 ft-lb/sec = 11.1 horsepower, most of which goes into creating the shock wave. Remember it’s a 3-D cone that travels great distance, and it gets its energy by stealing velocity from your bullet!
Mach 1.00 Bullet Flight Image
Many shots were fired to capture an image of the transonic shockwave structure at exactly Mach 1.00. With the bullet now moving at the speed of sound, the local airflow on some parts of the bullet exceeds Mach 1.0. Anytime something is moving thru the air faster than the air can get out of the way, you get a compression wave, aka “shock wave”. That’s what’s visible in this image — the areas where the air density changes rapidly (in the compression wave) are visible as near vertical lines and a detached bow wave out front. As the bullet progresses through transonic speed, this shockwave structure develops which has strong effects on the drag (wind sensitivity) and stability of the bullet.
The exact development of the shockwaves and the resulting effects are unique and sensitive to the bullet geometry, and become very difficult to predict through the transition from subsonic (incompressible flow without shock waves) to supersonic (compressible flow with shock waves). Each bullet geometry does this differently which is why it’s difficult to determine transonic stability criteria for bullets of different shapes.
Mach 0.86 Bullet Flight Image
Here’s a bullet at Mach 0.86 (86% the speed of sound, which is 962 FPS at 61° F). As you can see, this 0.86 Mach is not fast enough to make any discernable waves but you can see turbulence in the bullet wake (right side in photo). The beginning of small shock waves can be seen on the bullet tip, and at the bearing surface/boat tail juncture. For the most part, all of the airflow around this bullet is subsonic. You wouldn’t hear a supersonic ‘crack’ from this bullet flying past the observer.
In discussions of ballistics, you’ll see references to “tangent”, “secant”, and “hybrid” bullet shapes. We know that, for many readers, these terms can be confusing. To add to the confusion, bullet makers don’t always identify their projectiles as secant or tangent designs. This article provides a basic explanation of tangent, secant, and hybrid ogive bullet designs, to help you understand the characteristics of these three basic bullet shapes.
Tangent vs. Secant vs. Hybrid
Most match bullets produced today use a tangent ogive profile, but the modern VLD-style bullets employ a secant profile. To further complicate matters, the latest generation of “Hybrid” projectiles from Berger Bullets feature a blended secant + tangent profile to combine the best qualities of both nose shapes. The secant section provides reduced drag, while the tangent section makes the bullet easier to tune, i.e. less sensitive to bullet seating depth position.
Berger Bullets ballistician Bryan Litz explains tangent and secant bullet ogive designs in a glossary section of his Applied Ballistics website, which we reprint below. Bryan then explains how tangent and secant profiles can be combined in a “hybrid” design.
How Bullet Ogive Curves are Defined
While the term “ogive” is often used to describe the particular point on the bullet where the curve reaches full bullet diameter, in fact the “ogive” properly refers to the entire curve of the bullet from the tip to the full-diameter straight section — the shank.
Understanding then, that the ogive is a curve, how is that curve described?
LITZ: The ogive of a bullet is usually characterized by the length of its radius. This radius is often given in calibers instead of inches. For example, an 8 ogive 6mm bullet has an ogive that is a segment of a circular arc with a radius of 8*.243 = 1.952”. A .30-caliber bullet with an 8 ogive will be proportionally the same as the 8 ogive 6mm bullet, but the actual radius will be 2.464” for the .30 caliber bullet.
For a given nose length, if an ogive is perfectly tangent, it will have a very specific radius. Any radius longer than that will cause the ogive to be secant. Secant ogives can range from very mild (short radius) to very aggressive (long radius). The drag of a secant ogive is minimized when its radius is twice as long as a tangent ogive radius. In other words, if a tangent ogive has an 8 caliber radius, then the longest practical secant ogive radius is 16 calibers long for a given nose length.”
Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths
Ogive Metrics and Rt/R Ratio
LITZ: There is a number that’s used to quantify how secant an ogive is. The metric is known as the Rt/R ratio and it’s the ratio of the tangent ogive radius to the actual ogive radius for a given bullet. In the above example, the 16 caliber ogive would have an Rt/R ratio of 0.5. The number 0.5 is therefore the lowest practical value for the Rt/R ratio, and represents the minimum drag ogive for a given length. An ogive that’s perfectly tangent will have an Rt/R ratio of 1.0. Most ogives are in between an Rt/R of 1.0 and 0.5. The dimensioned drawings at the end of my Applied Ballistics book provide the bullets ogive radius in calibers, as well as the Rt/R ratio. In short, the Rt/R ratio is simply a measure of how secant an ogive is. 1.0 is not secant at all, 0.5 is as secant as it gets.
Hybrid Bullet Design — Best of Both Worlds?
Bryan Litz has developed a number of modern “Hybrid” design bullets for Berger. The objective of Bryan’s design work has been to achieve a very low drag design that is also “not finicky”. Normal (non-hybrid) secant designs, such as the Berger 105gr VLD, deliver very impressive BC values, but the bullets can be sensitive to seating depth. Montana’s Tom Mousel has set world records with the Berger 105gr VLD in his 6mm Dasher, but he tells us “seating depth is critical to the best accuracy”. Tom says a mere .003″ seating depth change “makes a difference”. In an effort to produce more forgiving high-BC bullets, Bryan Litz developed the hybrid tangent/secant bullet shape.
Many barrel-makers mark the twist rate and bore dimensions on their barrel blanks.
Does muzzle velocity change with faster or slower barrel twist rates? Absolutely, but much less than you might think. Faster twist rates do slow down bullets somewhat, but the speed loss is NOT that significant. With Bartlein .308 Win barrels of identical length and contour, a 1:12″-twist barrel was only 8 fps faster than a 1:8″-twist barrel. That was the result of testing by Applied Ballistics.
The Applied Ballistics team tested six (6) same-length/same-contour Bartlein barrels to observe how twist rate might affect muzzle velocity. This unique, multi-barrel test is featured in the book Modern Advancements in Long Range Shooting, Vol. 1. That book includes other fascinating field tests, including a comprehensive chronograph comparison.
Barrel Twist Rate vs. Velocity — What Tests Reveal by Bryan Litz
When considering barrel twist rates, it’s a common belief that faster twist rates will reduce muzzle velocity. The thinking is that the faster twist rate will resist forward motion of the bullet and slow it down. There are anecdotal accounts of this, such as when someone replaces a barrel of one brand/twist with a different brand and twist and observes a different muzzle velocity. But how do you know the twist rate is what affected muzzle velocity and not the barrel finish, or bore/groove dimensions? Did you use the same chronograph to measure velocity from both barrels? Do you really trust your chronograph?
Summary of Test Results
After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 FPS per inch of twist. In other words, your velocity is reduced by about 5 FPS if you go from a 1:12″ twist to a 1:8″ twist. — Bryan Litz
Savage Test Rifle with Six Bartlein Barrels
Most shooters don’t have access to the equipment required to fully explore questions like this. These are exactly the kinds of things we examine in the book Modern Advancements in Long Range Shooting, Vol. 1. In that book, we present experiments conducted in the Applied Ballistics lab. Some of those experiments took on a “Myth Buster” tone as we sought to confirm (or deny) popular pre-conceptions. For example, here’s how we approached the question of barrel twist and muzzle velocity.
Six .308 Win Barrels from Bartlein — All Shot from the Same Rifle
We acquired six (6) barrels from the same manufacturer (Bartlein), all the same length and contour, and all chambered with the same reamer (SAAMI spec .308 Winchester). All these barrels were fitted to the same Savage Precision Target action, and fired from the same stock, and bench set-up. Common ammo was fired from all six barrels having different twist rates and rifling configurations. In this way, we’re truly able to compare what effect the actual twist rate has on muzzle velocity with a reasonable degree of confidence.
Prior to live fire testing, we explored the theoretical basis of the project, doing the physics. In this case, an energy balance is presented which predicts how much velocity you should expect to lose for a bullet that’s got a little more rotational energy from the faster twist. In the case of the .30 caliber 175 grain bullets, the math predicts a loss of 1.25 fps per inch-unit of barrel twist (e.g. a 1:8″ twist is predicted to be 1.25 fps slower than a 1:9″ twist).
Above, data shows relationship between Twist Rate and Muzzle Velocity (MV) for various barrel twist rates and rifling types. From fast to slow, the three 1:10″ twist barrels are: 5R (canted land), 5 Groove, 5 Groove left-hand twist.
We proceeded with testing all 6 barrels, with twist rates from 1:8″ to 1:12″. After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 fps per inch of twist. In other words, your velocity is reduced by about 5 fps if you go from a 1:12″ twist to a 1:8″ twist. [Editor: That’s an average for all the lengths tested. The actual variance between 1:12″ and 1:8″ here was 8 FPS.] In this case the math prediction was pretty close, and we have to remember that there’s always uncertainty in the live fire results. Uncertainty is always considered in terms of what conclusions the results can actually support with confidence.
This is just a brief synopsis of a single test case. The coverage of twist rates in Modern Advancements in Long-Range Shooting Vol. 1 is more detailed, with multiple live fire tests. Results are extrapolated for other calibers and bullet weights. Needless to say, the question of “how twist rate affects muzzle velocity” is fully answered.
Other chapters in the book’s twist rate section include: · Stability and Drag — Supersonic
· Stability and Drag — Transonic
· Spin Rate Decay
· Effect of Twist rate on Precision
Other sections of the book include: Modern Rifles, Scopes, and Bullets as well as Advancements in Predictive Modeling. This book is sold through the Applied Ballistics online store at thescienceofaccuracy.com. Modern Advancements in Long Range Shooting is also available as an eBook in Amazon Kindle format.
Train Wrecks (and How to Avoid Them)
4. Wind Issues. Tricky winds derail many trains. A lot can be written about wind strategies, but here’s a simple tip about how to take the edge off a worse case scenario. You don’t have to start blazing away on the command of “Commence fire”. If the wind is blowing like a bastard when your time starts, just wait! You’re allotted 30 minutes to fire your string in long range slow fire. With average pit service, it might take you 10 minutes if you hustle, less in F-Class. Point being, you have about three times longer than you need. So let everyone else shoot through the storm and look for a window (or windows) of time which are not so adverse. Of course this is a risk, conditions might get worse if you wait. This is where judgment comes in. Just know you have options for managing time and keep an eye on the clock. Saving rounds in a slow fire match is a costly and embarrassing train wreck.
Bryan tolds us: “We tested many types of .22 rimfire ammo for the 2nd Edition of the 
Hybrid Bullet Design — Best of Both Worlds?
