The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.
Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”
The simple answer to that is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.
G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.
Drag Models — G7 is better than G1 for Long-Range Bullets
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of Applied Ballistics for Long Range Shooting, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they’re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here’s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:
G1 BCs, averaged between 1500 fps and 3000 fps:
Berger 180 VLD: 0.659 lb/in²
JLK 180: 0.645 lb/in²
The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).
For bullets like these, it’s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.
Many modern ballistics programs, including the free online JBM Ballistics Program, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.
[Editor's NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]
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iPhone and iPad users rejoice. The Apple iOS version of the Applied Ballistics Mobile App is now available. It has all the features of the much-loved Applied Ballistics Android App with full Apple functionality. This mobile App will run on iPhones, iPods, and iPads.
The new iOS mobile App accounts for all major and minor trajectory variables that a shooter could encounter. Conveniently, the App displays single-shot solutions in HUD View or Reticle View.
Real-World Calibration — Shooters can enter their observed drops and the program will calibrate and “true” the predictions based on actual bullet impact. This is done by incorporating muzzle velocity and drop-scaling over various segments of the trajectory.
Sync to Web — A web-sync feature allows you to store your rifle and ammunition libraries online. And you can backup all the profiles online or restore them to a device.
Forum member Snuggie308, who acquired the new iOS App, gives it a thumbs up: “I bought it last night. It is a great tool. There’s a massive data base … built into it. You can’t find a better [mobile ballistics app] in my opinion.” Snuggie308 also reports that the new iOS is iPad friendly, and fills the iPad screen so it is easy to use all the features.
The Applied Ballistics iOS Mobile App runs the state-of-the-art Point Mass ballistic solver. This solver, along with the built-in library of ballistic coefficients, makes this the most accurate, precise, and complete mobile ballistics app available for iOS devices.
Ballistician (and former missile design engineer) Bryan Litz wrote this solver. The program integrates the equations of ballistic motion numerically, using a 4th-order Runge-Kutta method, the preferred method of solving dynamic equations for aircraft and missiles. The application also comes with G1 and G7 BCs for over 1,300 bullet types.
Bryan Litz tells us: “We have worked extensively on this product. With the success of the Android version of the application, released two years ago, the demand for the iOS version has been high. We are excited to now offer a full-featured iOS version that runs on iPhones, iPods, and iPads.”
Available now through iTunes, the Applied Ballistics Mobile App costs $29.99, and requires iOS 7.0 or later for proper functionality. Compatible with iPhone, iPad, and iPod touch devices, this App is optimized for the iPhone 5 series of smart phones.
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“This new series is heavily based in experimental ballistics, and takes a ‘Myth Busters’-type approach to many of the questions and problems faced by modern long range shooters,” stated Litz. Volume I of the series is scheduled for release in late July, 2014. The book will cost $39.95, but you can pre-order now for $35.95, a 10% savings.
Bryan adds: “Anyone interested in the underlying science behind shooting can benefit from this book. We address the important questions… How much does faster twist affect MV? How does stability affect BC from the muzzle and downrange? What chronographs are capable of high accuracy and precision? What characteristics should you look for in your long range rifle and optic set up? What new gadgets are being developed to enhance long range shooting?
New Book Features Extensive Live-Fire Test Results
Bryan tells us: “The book spotlights state-of-the-art technologies (and methodologies) in long range shooting. New equipment and old ideas are explored using experimental, live-fire testing. Extensive test results are reported in an easy-to-understand way. Among other things, our tests explore the effects of twist rate on muzzle velocity, BC (supersonic and transonic), precision, even spin rate decay for various rifling profiles as they are tested experimentally.
Chronographs and Optics Are Tested and Compared
Litz’s new book traces the evolution of modern rifle, bullet, and optic design. Results from chronograph comparison tests are presented, showing the strengths and weaknesses of available commercial chronographs. High-tech instrumentation such as laser rangefinders and wind measurement devices are explained in detail by contributing author Nick Vitalbo.
The New Book Puts Theory into Practice
We asked Bryan Litz how this new book differs from his previous treatises. Bryan replied: “My original Applied Ballistics for Long-Range Shooting book explains the fundamental elements of external ballistics. It’s the academic background which all future work relies on. The new book, Modern Advancements in Long Range Shooting, covers the ongoing development of equipment and ideas. We explore things like twist rate effects, modern rifle and optic design, and some of the high tech instruments which are being used to enhance the effectiveness of long range shooting.
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Bryan Litz shot his first F-TR match recently, and he came up a winner — a big winner. Competing at the Midwest Palma event, Bryan topped the F-TR field, winning by 15 points. In fact Bryan ended up finishing within 10 points of F-Open winner Alex Lipworth. In the 20-shot, 1000-yard matches, Bryan averaged an impressive 195-7X, with a stunning 196-11X score in one match. (Consider that the 1000-yard X-Ring is just five inches in diameter!) Not bad for Bryan’s first attempt at the F-TR game.
We all know Bryan has serious long-range shooting skills. But he also had a secret weapon — a wickedly accurate, wood/carbon-stocked, low-profile F-TR rifle built by John Pierce. With this Pierce rifle, Bryan had to abandon the hard-holding style he uses in sling-shooting competition. Instead he adopted a “less is more”, almost-free-recoil method — and it worked. Is this the future of F-TR? Read on and learn what Bryan has to say about F-TR shooting, “belly benchrest” style.
Sling Shooter Tries F-TR
by Bryan Litz
I’ve been coaching the Michigan F-TR team for a while and finally decided to participate in the competition. F-TR is more rifle-centric than Palma, meaning the precision demands are greater due to the smaller scoring rings. After seeing Eric Stecker’s results with his Pierce rifle at the 2014 Berger Southwest Nationals, I asked my good friend and Michigan team-mate John Pierce to “build me one like Eric’s”. This is the same basic set up as John’s own F-TR rifle as well. It’s a Pierce F-TR action with a 30″ long, 1:9″ twist Bartlein Barrel chambered for the Berger 215gr Hybrids. The barreled action is bedded into a light-weight, BR-style stock built by Bob Scoville. A Phoenix bipod underneath and a Nightforce 15-55X Competition scope complete the package.
Click Image to Zoom
Loading the .308 Winchester with Berger 215gr Hybrids
I received the rifle just one week before the Midwest Palma match. During that week prior to the match, I put over 700 rounds on the rifle. I did some load development but was mostly learning to shoot a new rifle in a new discipline. I settled on 215gr Berger Hybrids seated 0.015″ off the riflings over a stout charge of Varget in Lapua Palma (small primer) brass with CCI BR4 primers. The only brass prep was mandreling the necks of the new brass for consistent neck tension. Bullets were slightly pointed, but nothing was segregated by weight, base-to-ogive, or anything. All the ammo I shot in Lodi was loaded in brand-new Lapua brass.
Check Out Bryan’s Set-up with the Rifle (Click Photo to Zoom)
Learning the F-TR Game — Adapting to a New Shooting Style
Coming over from sling shooting, I knew there would be unique challenges to F-TR which I wanted to learn prior to (not during) a major tournament. I learned a new shooting position which doesn’t involve drawing the right knee up. For F-TR I get more straight behind the gun rather than at an angle. I found that the rifle shoots best with very light cheek, shoulder and grip pressure, approaching free recoil. This is how Eric Stecker shot his similar rifle into second place in the SW Nationals. I learned the rifle’s sensitivity to different bipod and rear bag supports, and found the best buttplate position to allow the rifle to track and stay on target after recoil. This set-up shot best with a mostly free-recoil approach, that means “hovering” over the comb, rather than resting your head on the stock. This took some “getting used to” in terms of neck and back muscle tone. These are the kind of details I think it’s important to focus on when entering a new dicipline.
“I love the way this Pierce F-TR rifle flings brass, and wins tournaments. None of my sling guns ever had an ejector. With this rig, it’s become one of my favorite things to eject the brass and just let it fly!”
I think many shooters consider themselves ‘ready for a match’ the first time the rifle shows them a couple 1/3 or 1/4 MOA 5-shot groups from a bench at 100 yards. While making the rifle shoot precisely is certainly a prerequisite for successful match shooting, it’s certainly not the whole story. So as soon as I got the load and rifle shooting 1/2 MOA from the bench, I proceeded to shoot many 10- and 20-shot strings from the ground at 300 and 1000 yards. I shot more than 500 rounds this way, studying the rifles character, and learning to shoot it. It’s amazing how much the precision (grouping) is affected by subtle variables in the set-up, especially when shooting heavy bullets. I truly believe that many F-TR rifles are hindered in their precision potential by something in the way they are set up and shot.
Advice on Shooting the Heavy Bullets in a .308 Win
I believe F-TR set-ups are way more forgiving with light- to medium-weight bullets (155 to 185 grains). By this I mean that it’s easier to shoot good groups with a variety of bipods, rear bags, etc. But as you get into the 200 – 215 grain bullet weights, the precision of the rifle (i.e. group size) becomes very sensitive to set-up and shot execution. I was able to find a good set-up which let the rifle shoot very well on a variety of surfaces (hard gravel, soft grass, sand, etc.). In Lodi, the rifle shot well all week.
Having done so much preparation and training with the rifle the week prior to the match, I felt very prepared and confident. The results were actually better than expected. There were no problems at all with equipment, and I just shot the rifle the way it liked to be shot. In the end, I won the F-TR Division. I can say there were many shooters interested in the Pierce rifle!
Bryan observes that this rifle held 1/2 MOA of vertical at 1000 yards for 17 out of 20 shots. That’s impressive accuracy. Bryan was in first place each day of the match, including the 3×1000 on Friday where he averaged over 195-7X. Remarkably, Bryan finished just 10 points behind the F-Open winner, with the next closest F-TR competitor 15 points behind Bryan. In fact, with his .308 Win, Bryan out-scored 75% of the F-Open shooters. CLICK for match results.
Bryan gave credit to his smiths and his team-mates: “I’d like to thank John Pierce for building a great F-TR rifle and thank my dad, Bill Litz, for loading the best ammo on the planet. Finally, I’d like to thank the Michigan F-TR team for helping me learn how to shoot F-TR.”
Bryan writes: “Here I am with ‘The Man’, John Pierce, and the epic F-TR rifle he built for me. This thing shoots ‘No S***’ 1/2 MOA Vertical at 1000 yards.”
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Ballistics books have gone digital. Bryan Litz’s Applied Ballistics For Long-Range Shooting (2nd Edition), the leading treatise on the subject, is now available in digital eBook format. This new eBook version contains all the text of the print version, all the charts, all the diagrams, and all the photos. You get all this in an easy-to-read, easy-to-search format that can be viewed on a variety of devices*. You can access the book on your home computer, on your laptop, on a tablet, on a smartphone, or on a lightweight, portable Kindle e-Reader. And yes, iPad users can use the Kindle app to read the book on an iPad.
NOTE: After clicking this link to go to Amazon.com, click on the blue book image labeled “Look Inside”. This will launch a preview window. Alternatively, Kindle users can click the “Send Sample Now” button.
Advantages of the eBook Edition
The eBook release of Bryan Litz’s most popular and comprehensive ballistics book is a big deal, in our opinion. There are many advantages to the digital format. First you can quickly search for any term or reference, or click from table of content entries to desired chapters. Second, you can highlight text and bookmark pages for future review. Third, you can easily change the font size to enhance reading for older eyes. Fourth, you can zoom in the charts, diagrams, and photos for a better view. Last but not least, you can easily carry the entire text in the field on the same digital device that holds your ballistics solver software.
Highlights of eBook Edition
The eBook version of Applied Ballistics for Long-Range Shooting (2d Ed.) is available now on Amazon.com. Since its release in 2011, the second edition (hardcopy) of Applied Ballistics for Long Range Shooting has sold over 10,000 copies. It’s the modern ‘go to’ book on the subject of ballistics for long range shooters. The Second Edition of the book includes two additional chapters covering extended long-range shooting and monolithic bullets.
200 Bullet Types Tested. In this eBook edition, Bryan Litz includes data from his own personal field tests with over 200 bullet types. Performance data (G1 and G7 BCs confirmed by live-fire testing) is presented along with 2-D drawings for hundreds of long range bullets.
Ballistic Program Included. eBook buyers can receive the Point Mass Ballistics Solver 2.0 for no extra charge. The software comes on a CD with the hardcopy. With the eBook, there are two ways to access the ballistics program. First, you can access the free AB online ballistics solver through embedded links in the eBook and run directly from your eReader. Alternatively, you can request the PM Solver program to be emailed to you for running on a PC.
“Our mission at Applied Ballistics is to be the complete and unbiased source of external ballistics information for long range shooters,” stated Bryan Litz, author and owner of Applied Ballistics, LLC. “We’re constantly testing new claims, products and ideas and dispensing the marketing hype which can make it difficult for shooters to master the challenging discipline of long range shooting. We developed the original hard copy of the book in order to provide shooters of all capabilities with this knowledge. The release of the eBook will not only provide readers with the same knowledge, but do so in a more accessible and mobile way.”
Sample Page from eBook
* Installation of FREE eReader software may be required for viewing on desktop computers, laptops, tablets, and smartphones. This only takes a minute or so.
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Two months ago, the Daily Bulletin featured Six Shooting Tips by Bryan Litz. That article was hugely popular with our Bulletin readers and Facebook fans. In that article, as his Competition Tip Number Three, Bryan told readers to “Actively avoid major train wrecks”. In other words, you must avoid the big disasters (such as equipment failures) that can ruin a whole match. In this follow-up article, 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.
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!
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Berger’s customers said “Make more bullets!”, and the company listened. Over the next few months Berger will more than double its capacity, by adding SIX new bullet-making machines, up from five at the beginning of 2013. You can do the math: 5 + 6 = 11. That means that Berger will have more than twice as many machines turning out bullets for the yellow and orange boxes. Bringing six new machines online represents a major commitment by Berger to increased production. This has been the “number one priority” for the company according to Berger ballistician Bryan Litz.
Bryan explained that Berger has already increased its output in recent months. In 2013 Berger produced 45% more bullets than in 2012. That’s a big boost. But, Bryan added, even with that 45% greater output, demand was out-stripping supply. So Berger determined the best long-term solution was to increase production capacity… and that meant acquiring new bullet-making machines. So 2014 will mark the “Rise of the Machines” at Berger, and that’s good news for fans of Berger Bullets. Within a few months you should see much greater availability of Berger bullets at gun stores and online vendors.
Bryan Litz Explains That Berger is Doubling Production Capacity This Year (SHOT Show Report)
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More and more people are reading books on tablet computers and eReader devices such as the Kindle and Nook. Recognizing the demand for digital resource works, Applied Ballistics has just releases of its first eBook — a digital version of Accuracy and Precision for Long Range Shooting. This work (which has sold 5000 hard copy versions), is now available in electronic format for both Kindle and Nook eReaders. iPad users can use the Kindle app to access the eBook.
This book discusses how to evaluate multiple variables to improve your hit percentage. It explains how to correct the trajectories for drop, wind deflection, etc. through the use of Weapon Employment Zone (WEZ) analysis. WEZ is applied throughout the book, showing readers how to get more rounds on targets, more reliably. Case studies (with live fire verification for many scenarios) show what things affect your hit probability at long range.
All formats of the eBook are sold for $27.99 (hardcopy is $34.99). The Kindle book is available directly from Amazon.com, while the Nook version can be purchased from BarnesandNoble.com.
Free eReader Content on Applied Ballistics Website
If you have a Kindle, Nook, or iPad, you should visit the Ballistics website. You’ll find many free technical articles you can download as PDF files or in Kindle format or Nook format. To access these FREE articles, select the “Recreational” or “Professional” tabs on the top of the Applied Ballistics home page, then choose the “Articles” link from the pull-down menu. Bryan Litz tells us: “We recently updated our website and we’ve included a number of free articles about bullet design, long-range ballistics, and aspects of WEZ analysis. You don’t need an eReader for these — just download the PDF versions.”
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Applied Ballistics LLC has launched a completely updated website with many new features including an archive of FREE articles plus a full-featured online ballistics calculator. If you are interested in precision shooting, you should visit the “new and improved” Applied Ballistics website. Browse through the new content and try out the advanced Ballistics Calculator.
NEW Online Ballistics Calculator
There are many free online ballistics calculators, but the new Applied Ballistics web utility goes far beyond other web-based options. Bryan Litz states: “No ballistic solution can be more accurate than its inputs”. Accordingly, Applied Ballistics offers the most reliable BC data available — a built-in library of measured G1 and G7 BCs for over 200 bullets. The Online Ballistics Calculator also allows you to “offload” your results for use in the field in two ways. First, you can save a file for transfer to an Applied Ballistics Kestrel. (This process is supported with a ‘save profile’ option from the output page.) Alternatively, you can send the ballistics profile to Accuracy First DG to have a whiz wheel created.
The Online Ballistics Calculator has many “advanced” features. For example, you can enter sight scale factors to account for scopes which don’t track perfectly true, and also zero offsets which allows you to compensate for imperfect zeros. In addition, this is the first online ballistics program to provide dynamic WEZ (Weapon Employment Zone) analysis. This WEZ feature gives users the ability to calculate hit percentage on targets at a variety of ranges (and in various environments).
Bullet Data Files
The new website provides a number of detailed bullet data files. These data files include geometric dimensions, drag/BC data at multiple velocities, and detailed stability maps. The information is based on direct measurements and live fire testing conducted by Applied Ballistics.
The new Applied Ballistics website features a “digital library” of authoritative articles in PDF and eReader (Kindle, Nook) formats. You can download these FREE articles by clicking on the “Recreational” and “Professional” tabs at the top of Applied Ballistics Home Page, and then selecting “Recreational Articles” or “Professional Articles” from the pull-down menus.
Sample Ballistics Article Gyroscopic (Spin) Drift and Coriolis Effect
Most long range shooters are aware of the effects of gravity, air resistance (drag), and wind vectors on their bullets’ trajectory. Gravity, drag, and wind are the major forces acting on a bullet in flight, but they’re not the only forces. In this article, Bryan Litz explains some of the more subtle forces that influence a bullet’s flight.
Sample Professional Article 300 Winchester Magnum vs. 338 Lapua Magnum WEZ Analysis
The specific intent of this Weapon Employment Zone (WEZ) report is to compare the ballistic performance of the 300 Winchester Magnum to the 338 Lapua Magnum with several available ammunition types. Understanding how these weapons compare in terms of hit percentage is important in the context of modern military applications.
Applied Ballistics is involved in some advanced, special projects. The new website showcases some of these high end ballistics solutions. Bryan Litz notes: “We have an active ballistics laboratory, highly capable contractors and industry partners who all contribute to provide practical and accurate solutions for a range of recreational and professional applications.”
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SHOT Show 2014 kicks off in two weeks in Las Vegas. While at SHOT Show next month, we plan to get the “inside scoop” on new bullet designs from Berger, Hornady, Lapua, Nosler and Sierra.
At SHOT Show 2012 we chatted with Berger Ballistician Bryan Litz about Berger’s popular line of Hybrid bullets. Berger now offers a wide range of Hybrids in multiple calibers and weights. In fact, for .30-Caliber shooters, Berger now offers seven different Hybrid match bullets, with weights from 155 grains up to 230 grains. Two .338-caliber OTM Tactical Hybrids were introduced in 2012 (a 250-grainer and a 300-grainer).
Bryan tells us: “The hybrid design is Berger’s solution to the age old problem of precision vs. ease of use. This design is making life easier for handloaders as well as providing opportunities for commercial ammo loaders who need to offer a high performance round that also shoots precisely in many rifles with various chamber/throat configurations.”
For those not familiar with Hybrid bullets, the Hybrid design blends two common bullet nose shapes on the front section of the bullet (from the tip to the start of the bearing surface). Most of the curved section of the bullet has a Secant (VLD-style) ogive for low drag. This then blends in a Tangent-style ogive curve further back, where the bullet first contacts the rifling. The Tangent section makes seating depth less critical to accuracy, so the Hybrid bullet can shoot well through a range of seating depths, even though it has a very high Ballistic Coefficient (BC).
In the video we asked Bryan for recommended seating depths for 7mm and .30-Caliber Hybrid bullets. Bryan advises that, as a starting point, Hybrid bullets be seated .015″ (fifteen thousandths) off the lands in most barrels. Watch the video for more tips how to optimize your loads with Hybrid bullets.
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In discussions of ballistics, you’ll see references to “tangent” and “secant” 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 and secant designs, to help you understand the characteristics of both 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.”
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.
Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths
Story sourced by Edlongrange.
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