U.S. Rifle Team (F-TR) Selects New Berger 200.20X Bullet for 2017 World Championships
Berger Bullets has released new .30 caliber bullet that could be a game changer for the F-TR discipline — a bullet with exceptional accuracy and very high BC. Berger’s NEW 200.20X Hybrid Target Bullet is the result of extensive research and development in partnership with the U.S. Rifle Team (F-TR), world champion shooters, and accuracy enthusiasts within the long range shooting community.
The new 200.20X has a 0.640 G1/0.328 G7 BC compared to 0.616 G1/0.316 G7 for the older 200 grain .30 caliber Hybrid. That’s a significant reduction in drag. Recommended twist for the new bullet is 1:10″, same as with the earlier 200-grainer.
Berger Chief Ballistician and U.S. Rifle Team (F-TR) member Bryan Litz said, “This is the ideal bullet for F-TR and similar long-range disciplines. The 200.20X has a longer boat tail and nose, with shorter bearing surface which equates to less drag, a higher ballistic coefficient, and fewer points lost to the wind. The BC of the new 200.20X is 4% higher than the existing 200 grain Target Hybrid (G7 BC of 0.328 vs. 0.316). The shorter bearing surface also makes the 200.20X easy to load and shoot in standard chambers. New shooters won’t need special reamers or costly gunsmithing to make this bullet perform.” Bryan himself is switching to the new 200.20X: “After winning the 2015 National Mid-Range and Long Range F-TR Championships with the Berger 215 grain Target Hybrid, I’m switching to the 200.20X because it’s an even better option.”
Bryan tells us that new 200-20X bullet requires a 1:10″ twist to achieve full stability and performance (BC) in most conditions, but you can shoot it out of a 1:11″ twist with a minor decrease in BC. For a stability analysis, enter this bullet in the Berger Stability Calculator with a weight of 200.2 grains, and a length of 1.508″ to get stability results for your particular rifle and atmospheric conditions.
After extensive field testing, this new 200.20X bullet has been adopted as the official .30 caliber match projectile for the U.S. Rifle Team (F-TR). The team verified that this new bullet offers very impressive performance — the higher BC equates to less wind drift, and this bullet has shown exceptional ability to “hold waterline”. Check out this 1000-yard group by Team member Dan Pohlabel, as shown on an electronic target monitor.
To learn more about the new .30 caliber 200.20X Hybrid Target Bullet and its development, visit the Berger Bullets Blog for details. These 200.20X bullets are available right now through your favorite authorized Berger Bullets vendors.
About the U.S. Rifle Team (F-TR)
The two- time World Champion, U.S. Rifle Team (F-TR) is comprised of 30 shooters and coaches who have dedicated themselves to four years of training and preparation to represent the United States at the 2017 World Championships to be held in Canada. They compete all over the world at various ranges out to 1,000 yards.
Buy Bullets and Support U.S. Rifle Team (F-TR)
Eric Stecker, President of Berger Bullets said, “We are proud to be the Official Bullet of the U.S. Rifle Team (F-TR). To support our team, Berger Bullets will donate $1.00 for every box of 200.20X bullets sold towards U.S. Team expenses for the upcoming 2017 F-TR World Championships, which will be held at the Connaught Ranges in Ottawa, Canada.”
Extreme Long Range — 2477 Yards
Notably, two Applied Ballistics team shooters made hits at 2477 yards. Just how far is that? Take a look at the photo above — that shows the location of the 2477-yard target with the firing line in the far distance. Now THAT is truly long range!
By Paul Phillips
I wanted to share a video that I made. This was from the King of 2 Miles event held recently in Raton, New Mexico. I was fortunate enough to be apart of an amazing team with Bryan Litz and Mitchell Fitzpatrick. We had some awesome sponsors: Berger Bullets, Nightforce Optics, McMillan Group International, Lethal Precision Arms LLC and Applied Ballistics LLC. Team Applied Ballistics took First, Second, and Fourth places out of 38 teams in this competition. Our Team highlight was working together to make first-round hits on a 24×36 inch plate at 1.4 miles. With me as coach, both Mitchell and Bryan made their first-round hits at 1.4 miles (2477 yards to be exact).
Video Shows Team Accomplishing Hits at 2477 Yards in Raton, NM
This event has been a personal goal of mine for a long time and I wanted to thank Bryan Litz and Mitchell Fitzpatrick for having me on the team. I call them quiet professionals. I also wanted to thank Kelly McMillan for sponsoring our team and being involved. Kelly has been an amazing sponsor and advocate for shooting sports and providing stocks and rifles for our military snipers for the past 40 years. I can’t forget to thank Ian Klemm for loaning me his Vortex Spotting scope with the MOA milling reticle. It worked great and was very fast to make corrections along with good glass.
Mitchell Fitzpatrick won the KO2M finals to earn the title “King of Two Miles”. He had a dominant performance shooting a .375 Lethal Precision Arms LLC rifle loaded with prototype solid 400gr Berger bullets. Mitchell built this rifle himself using a McMillan A5 Super Mag stock. Note: Berger has no current plans to market this .375-caliber bullet — it is still in the prototype stage.
Editor: Paul Phillips asked to make a special dedication, remembering a family member: “My brother Daniel Phillips passed away with brain cancer last year and this event was one that he wanted to video for me. I know he is smiling in heaven.”
Applied Ballistics team dominates the King of 2 Miles match: Mitchell Fitzpatrick (1st Place), Bryan Litz (2nd Place), and Paul Phillips (4th Place).
The King of 2 Miles event has come to an end, the scores have been tallied, and Team Applied Ballistics finished first, second, and fourth. That’s dominance. The “Top Gun” was young Mitchell Fitzpatrick, who blitzed the field with his impressive .375 Lethal Precision Arms LLC rifle shooting prototype solid 400gr Berger bullets. Mitchell built this rifle himself using a McMillan A5 Super Mag stock. Remarkably, Mitchell nailed first- and second-shot hits at the 2477-yard target, a full 1.4 miles away. That’s amazing shooting. The photo below illustrates the vast distance from firing line to target.
Mitchell gave credit to his team-mates: “We had the best ballistic solutions possible thanks to the work done at Applied Ballistics LLC by the one and only Bryan Litz. Bryan is also a world-class wind coach and world champion shooter. Paul Phillips, also a world-class wind coach, world champion shooter, and just an all-around class act. Paul was invaluable to making the wind calls we needed to win this match. One of the most important parts of any rifle system is the projectile… Berger’s new prototype .375-cal 400gr projectile we have been developing gave us a monumental ballistic advantage. [It was] without a doubt, a key to our success.”
Berger Ballistician Bryan Litz took second place shooting a .338 Edge (the only .338 rifle in the Finals). Durvin Wick finished third, while Paul Phillips, shooting Bryan’s rifle, placed fourth overall.
Report by Bryan Litz, Team Applied Ballistics
The 2016 King of 2 Miles event is in the books. Today the Top 10 teams engaged targets at 2011 yards, 2477 yards, and 3375 yards. All three Applied Ballistics teams had hits at 2011 yards, and two out of three of us scored first-round hits at 2477 yards! Note that no competitor (from any team) hit the two-mile (3375-yard) target, but that gives us a goal to shoot for next year. Many factors contributed to the success of the Applied Ballistics shooters in this event:
1. Teamwork. We shoot together on the U.S. Rifle Team. The standardized communication protocols between coaches and shooters was a big advantage in this timed event. We had excellent team-work, and are already discussing ways to improve and adapt our approach to ELR events.
2. Science. Applied Ballistics specializes in the science of accuracy. First round hits in this event are scored highly and you can get more first round hits if you know your ballistics. The top two shooters in this event both had first round hits at 2477 yards today which was key, and is not possible without highly accurate ballistic solutions.
3. Ballistic Performance. The performance of Mitchell Fitzpatrick’s .375 Lethal Precision Arms LLC rifle with the prototype 400 grain Berger Bullets solid is unmatched (G7 BC of 0.56 at over 3000 fps). This performance helped Mitch win the match by a sizable margin. The other two Applied Ballistics teams were shooting Bryan Litz’s .338 Edge with the Berger Bullets 300 grain Hybrid. Despite being a smaller caliber (compared to the .375s, .416s, and .50-calibers), the .338 Cal 300 grain Berger Hybrid proved to be a great performer.
There were quite a few big .50 Cals on the line, but a .375 topped the field. Sheri Judd photo.
Thanks to Eduardo Abril De Fontcuberta, Founder of the KO2M Event
We would like to thank all those who worked hard to make this event happen especially Eduardo Abril De Fontcuberta (shown below with Mitchell Fitzpatrick and Paul Phillips). Eduardo has worked hard to organize a great event that pushes the limits of ELR shooting in a fun and competitive way. We’re very grateful for the chance to participate and look forward to competing in the King of 2 Miles event next year. Also, thanks to Kelly McMillan for his support of our team. Kelly has been an awesome sponsor of our efforts here, as well as the U.S. Rifle Team, and the shooting community in general.
Any long range shooter knows that wind is our ultimate nemesis. The best ways of overcoming wind are to measure what we can and use computers to calculate deflection. The Applied Ballistics Kestrel is a great tool for this. As good as our tools may be, we don’t always have them at our fingertips, or they break, batteries go dead, and so on. In these cases, it’s nice to have a simple way of estimating wind based on known variables. There are numerous wind formulas of various complexity.
The Applied Ballistics (AB) Wind Hack is about the simplest way to get a rough wind solution. Here it is: You simply add 2 to the first digit of your G7 BC, and divide your drop by this number to get the 10 mph crosswind deflection. For example, suppose you’re shooting a .308 caliber 175-grain bullet with a G7 BC of 0.260 at 1000 yards, and your drop is 37 MOA. For a G7 BC of 0.260, your “wind number” is 2+2=4. So your 10 mph wind deflection is your drop (37 MOA) divided by your “wind number” (4) = 9.25 MOA. This is really close to the actual 9.37 MOA calculated by the ballistic software.
WIND HACK Formula
10 mph Cross Wind Deflection = Drop (in MOA) divided by (G7 BC 1st Digit + 2)
Give the AB wind hack a try to see how it works with your ballistics!
Some Caveats: Your drop number has to be from a 100-yard zero. This wind hack is most accurate for supersonic flight. Within supersonic range, accuracy is typically better than +/-6″. You can easily scale the 10 mph crosswind deflection by the actual wind speed. Wind direction has to be scaled by the cosine of the angle.
A Kestrel Wind Meter will record wind speed with its impeller wheel. However, to get the most accurate wind velocity reading, you need to have your Kestrel properly aligned with the wind direction. To find wind direction, first orient the Kestrel so that the impeller runs at minimal speed (or stops), and only then turn the BACK of the Kestrel into the wind direction. Do NOT simply rotate the Kestrel’s back panel looking for the highest wind speed reading — that’s not the correct method for finding wind direction. Rotate the side of the Kestrel into the wind first, aiming for minimal impeller movement. The correct procedure is explained below by the experts at Applied Ballistics.
How to Find the Wind Direction with a Kestrel Wind Meter
Here is the correct way to determine wind direction with a Kestrel wind meter when you have no environmental aids — no other tools than a Kestrel. (NOTE: To determine wind direction, a mounted Wind Vane is the most effective tool, but you can also look at flags, blowing grass, or even the lanyard on your Kestrel).
Step 1: Find the wind’s general direction.
Step 2: Rotate the Wind Meter 90 degrees, so that the wind is impacting the side (and not the back) of the wind meter, while still being able to see the impeller.
Step 3: Fine-tune the direction until the impeller drastically slows, or comes to a complete stop (a complete stop is preferred). If the impeller won’t come to a complete stop, find the direction which has the lowest impact on the impeller.
Step 4: Turn the BACK of the Kestrel towards the direction from which the wind is blowing. Then press the capture button, and record your wind speed.
Do NOT simply point the Kestrel’s back into the wind until you get the highest wind speed — that’s not the correct method.
After the success of its winter Ballistics seminar in Michigan, Applied Ballistics has taken its show on the road. Right now Bryan Litz and his team are running a seminar in Texas, and there will be two (2) more seminars this year — one in Michigan and one in North Carolina. These seminars cover a wide range of topics, with the primary focus on basic to advanced ballistics principles as applied to long-range shooting. Bryan uses a multi-media approach: “Everyone learns in different ways — some by reading, others process graphics better. The Applied Ballistics seminars offer a chance to engage industry professionals directly in person, and to ask your questions directly, in live conversation. This format is the best way for many shooters to learn the science of accuracy.”
AUDIO FILE: Bryan Litz Reports from the Ballistics Seminar in Texas on May 23rd. (Sound file loads when you click button).
To learn about upcoming seminars, watch a preview video, or get more information, CLICK THIS LINK. NOTE: If you want to get involved, places still remain for the summer and fall seminars. SEE Registration links below:
Full House in Texas — Ballistics Seminar is a Big Success
As you can see, this week’s seminar has been hugely popular, with over 130 shooters in attendence. Bryan Litz tells us: “Engagement at the Dallas seminar is great. With so many participants (130+), there’s a lot to discuss! Our content covers a lot of the aspects of long range ballistics, and the guys take the conversation into various applications such as hunting, competition shooting, and Military/LE applications as well. On Day One we covered basic and advanced trajectory features, Ballistic Coefficients, and laser rangefinder performance — all before lunch. In the afternoon we discussed wind from academic and practical standpoints. The afternoon session included a briefing by former USAMU team coach Emil Praslick, one of the best wind coaches in the world. After dinner there were informal break-out sessions with myself and guest speakers. Day Two (Tuesday) will be just as full — we’ll cover a lot of ground.”
There’s an all-new book from Applied Ballistics. Modern Advancements in Long Range Shooting – Volume II, is now available for pre-order from the Applied Ballistics eStore. This 356-page hardcover resource is chock full of information, much of it derived through sophisticated field testing. The pre-order price is $34.95, $5.00 off the regular $39.95 price. The books are expected to ship in July, 2016.
AUDIO FILE: Bryan Litz Talks about Modern Advancements in Long Range Shooting, Volume 2. (Sound file loads when you click button).
Volume II of Modern Advancements in Long Range Shooting contains all-new content derived from research by Applied Ballistics. Author Bryan Litz along with contributing authors Nick Vitalbo and Cal Zant use the scientific method and careful testing to answer important questions faced by long range shooters. In particular, this volume explores the subject of bullet dispersion including group convergence. Advanced hand-loading subjects are covered such as: bullet pointing and trimming, powder measurement, flash hole deburring, neck tension, and fill ratio. Each topic is explored with extensive live fire testing, and the resulting information helps to guide hand loaders in a deliberate path to success. The current bullet library of measured G1 and G7 ballistic coefficients is included as an appendix. This library currently has data on 533 bullets in common use by long range shooters.
Bryan tells us that one purpose of this book is to dispel myths and correct commonly-held misconceptions: “Modern Advancements in Long Range Shooting aims to end the misinformation which is so prevalent in long range shooting. By applying the scientific method and taking a Myth Buster approach, the state of the art is advanced….”
Bullet Dispersion and Group Convergence
Part 1 of this Volume is focused on the details of rifle bullet dispersion. Chapter 1 builds a discussion of dispersion and precision that every shooter will benefit from in terms of understanding how it impacts their particular shooting application. How many shots should you shoot in a group? What kind of 5-shot 100 yard groups correlate to average or winning precision levels in 1000 yard F-Class shooting?
Chapter 2 presents a very detailed investigation of the mysterious concept of group convergence, which is the common idea that some guns can shoot smaller (MOA) groups at longer ranges. This concept is thoroughly tested with extensive live fire, and the results answer a very important question that has baffled shooters for many generations.
Part 2 of this Volume is focused on various aspects of advanced hand-loading. Modern Advancements (Vol. II) employs live fire testing to answer the important questions that precision hand loaders are asking. What are the best ways to achieve MVs with low ES and SD? Do flash hole deburring, neck tension, primer selection, and fill ratio and powder scales sensitivity make a difference and how much? All of these questions are explored in detail with a clear explanation of test results.
One of the important chapters of Part 2 examines bullet pointing and trimming. Applied Ballistics tested 39 different bullet types from .224 through .338 caliber. Ten samples of each bullet were tested for BC in each of the following configurations: original out of the box, pointed, trimmed, pointed and trimmed. The effect on the average BC as well as the uniformity in BC was measured and tabulated, revealing what works best.
Part 3 covers a variety of general research topics. Contributing author Nick Vitalbo, a laser technology expert, tested 22 different laser rangefinders. Nick’s material on rangefinder performance is a landmark piece of work. Nick shows how shooters can determine the performance of a rangefinder under various lighting conditions, target sizes, and reflectivities.
Chapter 9 is a thorough analysis of rimfire ammunition. Ballistic Performance of Rifle Bullets, 2nd Edition presented live fire data on 95 different types of .22 rimfire ammunition, each tested in five different barrels having various lengths and twist rates. Where that book just presented the data, Chapter 9 of this book offers detailed analysis of all the test results and shows what properties of rimfire ammunition are favorable, and how the BCs, muzzle velocities and consistency of the ammo are affected by the different barrels.
Chapter 10 is a discussion of aerodynamic drag as it relates to ballistic trajectory modeling. You will learn from the ground up: what an aerodynamic drag model is, how it’s measure and used to predict trajectories. Analysis is presented which shows how the best trajectory models compare to actual measured drop in the real world.
Finally, contributing author Cal Zant of the Precision Rifle Blog presents a study of modern carbon fiber-wrapped barrels in Chapter 11. The science and technology of these modern rifle barrels is discussed, and then everything from point of impact shift to group sizes are compared for several samples of each type of barrel including standard steel barrels.
After the success of its recent winter Ballistics seminar in Michigan, Applied Ballistics has decided to take its show on the road, offering additional Ballistics seminars in three different states (Texas, Michigan, and North Carolina). These three seminars will cover a wide range of topics, with the primary focus on basic to advanced ballistics principles as applied to long-range shooting. Registration is now open for the three (3) upcoming Ballistics Seminars:
This video explains the subjects covered by Applied Ballistics Seminars:
Ballistician (and current F-TR National Mid-Range and Long-Range Champion) Bryan Litz will be the primary speaker at the spring, summer, and fall seminars. He will present material from his books and the Applied Ballistics Lab, and he will discuss his experience shooting in various disciplines. The seminar will feature structured presentations by Bryan and other noted speakers, but a great deal of time will be alloted for questions and discussion. By the end of the seminar, participants should have a much better understanding of how to apply ballistics in the real world to hit long-range targets. Along with Bryan, other respected experts will include:
Emil Praslick III – Head coach of the U.S. Palma team and retired head coach of the U.S. Army Marksmanship Unit. Emil will discuss tactics, strategy, and mindset for successful wind-reading.
Eric Stecker – Master Bulletsmith and President of Berger Bullets. Eric will be presenting on precision bullet making technology.
Nick Vitalbo – Owner of nVisti Tactical Innovations and chief engineer for Applied Ballistics. Nick will discuss the state of the art in laser rangefinders and wind reading devices.
Mitch Fitzpatrick – Applied Ballistics intern and owner of Lethal Precision Arms. Mitch specializes in Extended Long Range (ELR) cartridge selection and rifle design.
Ballistic Solvers – How they work, best practices, demos.
Weapon Employment Zone (WEZ) Analysis – How to determine and improve hit percentage.
Optics and Laser Technology – State of the Art.
The seminars costs $500.00. But consider this — each seminar participant will receive the entire library of Applied Ballistics books and DVDs, valued at $234.75, PLUS a free copy of Applied Ballistics Analytics software, valued at $200.00. So you will be getting nearly $435.00 worth of books, DVDs, and software. In addition, a DVD of the seminar will be mailed to each attendee after the seminar concludes.
Are you looking to improve your long-range shooting? Doubtless you’ve been thinking about upgrading your rifle or optics, but wonder what to buy (and how to get the best “bang for your buck”). In this video, Bryan Litz of Applied Ballistics offers “solid gold” advice on equipment selection for mid-level shooters (i.e. those who are somewhere between “newbie” and “Master of the Universe”). Bryan explains the logical first step is a barrel upgrade — a new tube from a top-barrel maker can make a huge difference. Then you should research the best factory ammo for your rifle, or get started in precision hand-loading. Bryan also offers advice on choosing a scope and optics accessories.
Equipment Upgrades: Barrel, Optics, Ammoby Bryan Litz
Every equipment element can be upgraded. You can run that factory rifle for a period of time, but the barrel eventually is going to be what holds you back. The twist rate probably won’t be fast enough to stabilize the high-BC bullets that you want to shoot at long range. So, the first thing you want to upgrade on your factory rifle is probably going to be the barrel. [With a new custom barrel] you’re going to get a fast twist rate, you’re going to get a chamber that’s optimized with a throat for your … bullet. And a good quality custom barrel is going to be easier to clean, won’t foul out as much, and it’s going to improve to overall accuracy and precision of your shooting. Barrel swaps are very common and routine thing for gunsmiths to do.
The next thing is improving your scope. If you don’t have a quality optic it’s going to hold you back. The job of the scope is to precisely and perfectly delineate [the target] within a half a degree (from 100 to 1000 yards is only a half a degree). The scope has got to put you on the money within that half a degree. So, it’s not a piece of equipment you want to go cheap on.
The other big factor is your ammunition. Getting into hand-loading is meticulous and it takes a long time to learn, but ultimately you’ll be making ammunition that is tailored for your rifle, and there simply won’t be anything better for your rifle than what you can develop through individual handloads.
So that’s typically the upgrade path: Get your factory rifle re-barreled, don’t skimp on a scope (or anything that attaches to it), improve your ammunition (whether by upgrading to better factory ammo or hand-loading on your own). All through this process is continuous learning… Once you have the best equipment (and it doesn’t get any better), the process of learning and education never ends. That is something you build on every single time you go to the range, and it’s what going to allow you to continually improve your skills.”
No matter what kind of rifle you shoot, whether it be an AR or a brenchrest rig, the principles are the same — develop a good load, learn the gun, hone your wind-reading skills, and practice in all conditions. Making a video of a practice session can help you identify and correct bad habits.
Bryan Litz says “don’t skimp on your scope”. Purchase a quality scope, rings, and scope level. Successful long-range shooting all begins with your view of the target.
Even with a top-of-the-line F-TR rig like this, you still have to practice diligently, putting in the “trigger time” needed to improve your game.
We will be interviewing Bryan Litz of Applied Ballistics tomorrow at SHOT Show in Las Vegas. As a sneak preview of some of the topics we’ll cover, here are some highlights of some important, original research conducted by Bryan and his Applied Ballistics team. Bryan wanted to know how much velocity was altered by twist rate. The “real world” test results may surprise you….
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. That book includes many 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?
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. 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 the testing in all 6 barrels from 1:8” to 1:12”. After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the 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 a surprising number — much less than most folks would predict.] 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 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. Modern Advancements in Long Range Shooting is also available in eBook format in the Amazon Kindle store.
Part 2 of this Volume is focused on various aspects of advanced hand-loading. Modern Advancements (Vol. II) employs live fire testing to answer the important questions that precision hand loaders are asking. What are the best ways to achieve MVs with low ES and SD? Do flash hole deburring, neck tension, primer selection, and fill ratio and powder scales sensitivity make a difference and how much? All of these questions are explored in detail with a clear explanation of test results.
