In this video, Bryan Litz of Applied Ballistics talks about Density Altitude and the effect of atmospheric conditions on bullet flight. Bryan explains why you must accurately account for Density Altitude when figuring long-range trajectories.
Bryan tells us: “One of the important elements in calculating a fire solution for long-range shooting is understanding the effect of atmospherics. Temperature, pressure, and humidity all affect the air density that the bullet’s flying through. You can combine all those effects into one number (value) called ‘Density Altitude’. That means that you just have one number to track instead of three. But, ultimately, what you are doing is that you are describing to your ballistics solver the characteristics of the atmosphere that your bullet’s flying through so that the software can make the necessary adjustments and account for it in its calculations for drop and wind drift.”
Bryan adds: “Once you get past 500 or 600 yards you really need to start paying careful attention to atmospherics and account for them in your ballistic solutions”. You can learn more about Density Altitude in Bryan’s book, Applied Ballistics for Long Range Shooting (Third Edition).
General Scientific Definition of Density Altitude
Density altitude is the altitude relative to the standard atmosphere conditions (ISA) at which the air density would be equal to the indicated air density at the place of observation. Density altitude can be calculated from atmospheric pressure and temperature (assuming dry air). Here is the formula:
Air is more dense at lower elevations primarily because of gravity: “As gravity pulls the air towards the ground, [lower] molecules are subject to the additional weight of all the molecules above. This additional weight means the air pressure is highest at sea level, and diminishes with increases in elevation”.*
Both an increase in temperature, decrease in atmospheric pressure, and, to a much lesser degree, increase in humidity will cause an increase in density altitude. In hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.
The USAMU recently published a “how-to” article about bullet sorting. While many of us may sort bullets by base-to-ogive length (and/or weight), the USAMU story explores the “how and why” of sorting bullets by Overall Length (OAL). Read the article highlights below, and make your own decision as to whether OAL sorting is worth the time and effort. Bryan Litz of Applied Ballistics says that sorting by OAL is not a bad idea, but base-to-ogive bullet sorting probably represents a better investment of your time.
Bullet Sorting by Overall Length
We’d like to share a specialized handloading technique which we’ve long found beneficial to our long-range (600 yards and beyond) accuracy. Sorting of bullets for extreme long range (LR) accuracy is not difficult to do, but some background in theory is needed.
Here at USAMU’s Handloading Shop, we only sort individual bullets for the most demanding Long-Range applications and important competitions. Only the most accurate rifles and shooters can fully exploit the benefits of this technique. The basic sorting process involves measuring the Overall Length (OAL) of the bullets, and grouping them in 0.001″ increments. It’s not unusual to find lots of match bullets that vary as much as 0.015″-0.020″ in length throughout the lot, although lots with much less variation are seen as well. Even in bullet lots with 0.015″ OAL variation, the bullet base-to-ogive length will show much less variation. Hence, our basic sort is by bullet OAL. One obvious benefit of sorting is easily seen in the attached photo. The few bullets that are VERY different from the average are culled out, reducing probable fliers.
How does one know what OAL increments to use when sorting? The answer is simple. As each lot of bullets is unique in its OAL distribution, it’s best to sample your bullet lot and see how they are distributed. In the attached photo, you will see a set of loading trays with a strip of masking tape running along the bottom. Each vertical row of holes is numbered in 0.001″ increments corresponding to the bullets’ OAL. A digital caliper makes this task much easier. As each bullet is measured, it is placed in the line of holes for its’ OAL, and gradually, a roughly bell-shaped curve begins to form.
Note that near the center, bullets are much more plentiful than near the edges. At the extreme edges, there are a few that differ markedly from the average, and these make great chronograph or sighting-in fodder. We recommend using a sample of 200 bullets from your lot, and 300 is even better. Some bullet lots are very consistent, with a tall, narrow band of highly-uniform bullets clustered together over just a few thousandths spread. Other lots will show a long, relatively flat curve (less uniform), and you may also see curves with 2 or more “spikes” separated by several 0.001″ OAL increments.
Bullet Sorting (OAL vs. Base-to-Ogive vs. Weight) — Litz Talks
I’m often asked what is a the best measure to sort bullets by, and the answer (to this and many other questions in ballistics) is: it depends.
Choosing to sort by overall length (OAL), base to ogive (BTO), bearing surface, weight, etc. can get overwhelming. Shooters typically look for something they can measure, which shows a variation and sort by that. It’s common for dimensional variations to correlate. For example, bullets which are longer in OAL are typically also shorter in BTO, and have longer noses. All these are symptoms of a bullet that was pushed a little further into the pointing die, or possibly had more than average lube while being swaged. So in essence, if you sort by BTO, you’re measuring one symptom which can indicate a pattern in the bullets shape.
So, the question still stands — what should you measure? You’ll always see more variation in OAL than BTO, so it’s easier to sort by OAL. But sometimes the bullet tips can be jagged and have small burrs which can be misleading. Measuring BTO will result in a lower spread, but is a more direct measure of bullet uniformity.
Then there’s the question of; how much variation is too much, or, how many bins should you sort into? Shooters who see 0.025” variation in BTO may choose to sort into 5 bins of 0.005”. But if you have only 0.005” variation in the box, you’ll still sort into 5 bins of 0.001”. What’s correct? You have to shoot to know. Live fire testing will answer more questions, and answer them more decisively than any amount of discussion on the subject. The test I recommend is to identify bullets on the extreme short end of the spectrum, and some on the extreme long end. Load at least 10 rounds of each, and take turns shooting 5-shot groups with them. If there is a difference, it will be evident. The results of the testing will answer your question of: should I sort based on X, Y, or Z?”
You can read more discussion on this and other similar subjects in the new Ballistics & Bullets board in the Accurateshooter.com forum. Heres a link to the thread which is discussing bullet sorting: Bullet Sorting Thread
The biggest Berger bullet ever is on its way. In early summer, Berger Bullets will unveil its first-ever .50-Caliber projectile and its first-ever solid. This new 750gr bullet, called the TItan (for Titanium), features heat-resistant CNC-machined Titanium bullet tips with threaded shafts. TItan bullet bodies are precisely tapped (with a fine pitch) to accept the threaded tips. This allows for ultra-precise tip alignment and perfect concentricity. Another benefit of this threaded attachment system is that hand-loaders can change out tips, selecting a particular tip profile for different applications. Initially three tip types will be offered: Hunting (for increased expansion), Match (for maximum BC), and Tactical (for military/LEO applications). The Match Tip gives the new TItan a spectacular 1.25 G1 BC.
The field-tested G7 BC is still “top-secret” but Bryan Litz reports: “The number we’ve seen with the prototype TItans is a game-changer… nothing will touch it.” How impressive is the new TItan? Bryan told us: “Look, I don’t want to let the cat out of the bag, but I’m building a new .50 just to shoot this thing, and we’re looking to go sub-MOA at 2500 yards.”
The Titanium bullet tips set the new Berger TItan apart from all other projectiles on the market. Berger Ballistician Bryan Litz noted: “We wanted the ability to adapt bullet performance to particular applications. With interchangeable bullet tips you can increase BC or increase terminal performance. In addition, with the Titanium material, we have the most heat-resistant bullet tips in the business. Compare the heat resistance of Titanium with any thing else — red, green, or otherwise.” Recently, Hornady rolled out a line of ELD™ match bullets with heat-resistant red plastic tips. Berger’s Titanium tips can withstand much higher temperatures than ANY polymer tips. “Our Titanium tips are essentially heat-proof. The amount of heat required to compromise the tips would melt your barrel first”, said a Berger production engineer.
Berger Bullets President Eric Stecker said the company considered other monikers for its super-sized .50 Caliber projectile before finalizing on the name “TItan”: “For the new .50 we needed something to top the ‘Juggernaut’ name we use for our big 30s. We thought about ‘Super-Solid’ and even considered calling the big .50 the ‘Berger King Whopper’, but that didn’t work for obvious reasons. We finally settled on ‘TItan’ because it means ‘big’ and has the Titanium connection, and we can trademark that. But Bryan and some of the production guys in the shop still call this big .50 the ‘Whopper'”.
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.
The Coriolis Effect comes into play with extreme long-range shots like this. The rotation of the earth actually moves the target a small distance (in space) during the course of the bullet’s flight. Photo by Dustin Ellermann at Whittington Center Range.
When you’re out at the range, the Earth seems very stable. But it is actually a big sphere zooming through space while spinning around its axis, one complete turn every 24 hours. The rotation of the earth can create problems for extreme long-range shooters. During extended bullet flight times, the rotation of the planet causes an apparent deflection of the bullet path over very long distances. This is the ballistics manifestation of the Coriolis Effect.
Bryan Litz of Applied Ballistics has produced a short video that explains the Coriolis Effect. Bryan notes that Coriolis is “a very subtle effect. People like to make more of it than it is because it seems mysterious.” In most common shooting situations inside 1K, Coriolis is not important. At 1000 yards, the Effect represents less than one click (for most cartridge types). Even well past 1000 yards, in windy conditions, the Coriolis Effect may well be “lost in the noise”. But in very calm conditions, when shooting at extreme ranges, Bryan says you can benefit from adjusting your ballistics solution for Coriolis.
Bryan explains: “The Coriolis Effect… has to do with the spin of the earth. You are basically shooting from one point to another on a rotating sphere, in an inertial reference frame. The consequence of that is that, if the flight time of the bullet gets significantly long, the bullet can have an apparent drift from its intended target. The amount [of apparent drift] is very small — it depends on your latitude and azimuth of fire on the planet.”
Coriolis is a very subtle effect. With typical bullet BCs and velocities, you must get to at least 1000 yards before Coriolis amounts to even one click. Accordingly, Bryan advises: “Coriolis Effect is NOT something to think about on moving targets, it is NOT something to think about in high, uncertain wind environments because there are variables that are dominating your uncertainty picture, and the Coriolis will distract you more than the correction is worth.”
“Where you could think about Coriolis, and have it be a major impact on your hit percentage, is if you are shooting at extended range, at relatively small targets, in low-wind conditions. Where you know your muzzle velocity and BC very well, [and there are] pristine conditions, that’s where you’re going to see Coriolis creep in. You’ll receive more refinement and accuracy in your ballistics solutions if you account for Coriolis on those types of shots. But in most practical long-range shooting situations, Coriolis is NOT important. What IS important is to understand is when you should think about it and when you shouldn’t, i.e. when applying it will matter and when it won’t.”
The Coriolis Effect — General Physics
The Coriolis Effect is the apparent deflection of moving objects when the motion is described relative to a rotating reference frame. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object’s speed in the rotating frame.
A commonly encountered rotating reference frame is the Earth. The Coriolis effect is caused by the rotation of the Earth and the inertia of the mass experiencing the effect. Because the Earth completes only one rotation per day, the Coriolis force is quite small, and its effects generally become noticeable only for motions occurring over large distances and long periods of time. This force causes moving objects on the surface of the Earth to be deflected to the right (with respect to the direction of travel) in the Northern Hemisphere and to the left in the Southern Hemisphere. The horizontal deflection effect is greater near the poles and smallest at the equator, since the rate of change in the diameter of the circles of latitude when travelling north or south, increases the closer the object is to the poles. (Source: Wikipedia)
Bryan Litz with his F-TR Nat’l Championship-winnning rifle, and the man who built it, John Pierce.
Bryan Litz knows something about bullet shapes and dimensions. He’s the chief designer of many of Berger’s projectiles, including the successful line of Hybrid bullets. Bryan also understands how bullets actually perform in “real world” competition. Bryan won BOTH the Mid-Range and Long-Range National F-TR Championships this year, a remarkable accomplishment. With Bryan’s technical expertise combined with his shooting skills, few people are better qualified to answer the question: “how should I sort bullets when loading for competition?”
Bullet Sorting Strategies — OAL vs. Base to Ogive
At the 2015 Berger Southwest Nationals, Forum member Erik Cortina cornered Bryan Litz of Applied Ballistics. Erik was curious about bullet sorting. Knowing that bullets can be sorted by many different criteria (e.g. weight, overall length, base to ogive length, actual bearing surface length etc.) Erik asked Bryan to specify the most important dimension to consider when sorting. Bryan recommended sorting by “Base to Ogive”. Litz noted that: “Sorting by overall length can be misleading because of the nature of the open-tip match bullet. You might get a bullet that measures longer because it has a jagged [tip], but that bullet might not fly any different. But measuring base to ogive might indicate that the bullet is formed differently — basically it’s a higher resolution measurement….”
Ballistics Q & A in Shooter’s Forum
Got more questions about bullets? Our Shooters’ Forum has a special area for Bullets & Ballistics topics. There you can get your own questions about bullets and ballistics answered by Bryan Litz and other experts from Applied Ballistics.
Here’s a valuable web resource our readers should bookmark for easy access in the future. ShootForum.com offers a vast Bullet Database, which includes roughly 3900 bullet designs in all. We counted nearly 200 different 6mm bullets! The bullet info comes from the makers of QuickLOAD Software. Access to the online database is FREE. Most database entries include Caliber, Manufacturer, Stated Bullet Weight, True Bullet Weight, Length, Sectional Density (SD), and Ballistic Coefficient.* In many cases multiple BCs are provided for different velocity ranges.
The database is great if you’re looking for an unusual caliber, or you want a non-standard bullet diameter to fit a barrel that is tighter or looser than spec. You’ll find the popular jacketed bullets from major makers, plus solids, plated bullets, and even cast bullets. For those who don’t already own QuickLOAD software, this is a great resource, providing access to a wealth of bullet information.
Values for Changed Bullet Designs
Some of our readers have noted some variances with BCs and OALs with recently changed bullet designs. In general the database is very useful and accurate. However, as with any data resource this extensive, there will be a few items that need to be updated. Manufacturers can and do modify bullet shapes. Kevin Adams, one of the creators of the database, explains: “Thanks for mentioning this database. It took us a long time to collate this information and have agreement to publish it. Please keep in mind that individual batches of bullets will differ from the manufacturers’ stated standards. This is more a reflection on the manufacturers’ tolerances than the database ‘accuracy’. We will continue to add to the database as more manufacturers’ figures come available.”
That smart phone in your pocket is really a miniature computer. What if you could harness that electronic brain to work as a weather meter? You’d just need a way to feed the smart phone environmental data — temperature, humidity, air pressure, wind velocity and so on. Well now that’s possible with the new $69.00 Weatherflow Smart Phone Weather Meter.
This portable, multi-function Weather Meter provides key weather data to your iOS and Android Mobile devices wirelessly via BlueTooth. The unit measures temperature, humidity, air pressure and dew points. With its built-in impeller, the Weather Meter will also record wind speed (average and gust), and wind direction. You can hand-hold it or attach it to a pole/tripod with a standard camera mount. This wireless Weather Meter is compatible with iPhone, iPad, iPod Touch and all major Android devices. The best thing is the price — right now the unit is just $69.00 at Amazon.com.
Reviews by Weather Meter Purchasers
By Wiley on October 2, 2015 — Verified Purchase
I own and love the original WeatherFlow Wind Meter but when I saw this new one that includes temperature, humidity and pressure for under $100, I had to have it. My new weather meter arrived two days after I ordered it and I am amazed at how good this thing is. Solid and well-built, it’s super comfortable in your hand. The hard carry case is nice. The App is pretty simple – start the App and push the button to connect. The meter connected without issue to my iPad mini and my Galaxy S5 (Android) phone. It displays the extra sensor information elegantly, and the data agrees very well with the Davis weather station on my neighbor’s house. Saving and sharing reports is simple. Something cool that’s not obvious until you play with the App a bit are the ‘more data’ you can see (wind chill, heat index, crosswind, headwind, and many others including some I didn’t know existed). I’ve used various Kestrel meters over years and while they are good sensors, Kestrel’s higher price and lack of smart phone integration (or any easy way to get data off the thing) have been frustrating. [Editor: Kestrel’s brand new 5000 Series Weather Meters do offer Bluetooth connectivity as an optional extra.]
By Richard W. on October 27, 2015 — Verified Purchaser
Great device for the price. It would be nice to interface it with ballistics Apps… but it provides relatively accurate readings and is very small. Finding wind direction is a bit manual (you have to face the device into the wind), but how hard is that? The Bluetooth connectivity is great, you don’t actually have to have it physically connected to the phone — you can put it where you need it.
Technical Details — Compatibility and Settings
The WeatherFlow Weather Meter processes data via a free downloadable App for iOS or Android. The unit works with Apple iPhones 4S or newer, Apple iPads Gen 3 or newer, iPod Touch, and “all major Android devices”. Wireless functionality requires support for Bluetooth version 4.0. You can select either English or Metric units via the “settings” menu. Wind speed units/range are 0.5 to 140 mph; 0.4 to 122 Knots; 0.8 to 225 kph; 0.2 to 63 m/s. Pressure units/range are: 8.9 to 32.5 inHg; 300 to 1100 mbar.
Product Tip from Boyd Allen. We welcome reader submissions.
Applied Ballistics LLC will offer its first-ever Ballistics Seminar early next year in Tustin, Michigan. This two-day seminar will feature Ballistician Bryan Litz and other experts including Eric Stecker, President of Berger Bullets, and Ray Gross, Captain of the U.S. F-TR Rifle Team. Bryan, the primary speaker, will present material from his books, the Applied Ballistics Lab, and his experience shooting in various disciplines. Bryan recently won both the Mid-Range and Long-Range F-TR National Championships. Bryan will be assisted by Nick Vitalbo, Owner of nVisti Tactical Innovations and lead engineer for Applied Ballistics. The seminar, held February 29 through March 1, 2016, will include classroom sessions followed by live fire demonstrations with sophisticated instrumentation.
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 seminar 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.
Bryan Litz explains: “Subjects will be introduced from an academic-first, principles perspective. Once the scientific basis for the material is established, the ideas are further demonstrated with examples from instrumented live fire. We explain the science, and then present examples of the principles in action. You’ll leave with an understanding of the subject matter, as well as a knowledge of how to apply it in the real world.” To learn more about the Ballistics Seminar, read this AccurateShooter Forum Thread.
Early Bird Special — Save $100.00
If you register before the end of December, 2015, you’ll receive $100.00 off the regular $500 registration fee. This $400.00 Early Bird Special price can be secured by registering through the Applied Ballistics online store.
The two-day seminar will be held at the Kettunen Center in Tustin Michigan. Lodging costs range from $115-$240 (all-inclusive). This price includes three meals each day, and starts at 3:00 pm the day before the seminar, and goes to breakfast the morning after the seminar concludes. Contact the Kettunen Center directly to reserve accommodations.
Have you recently purchased a new scope? Then you should verify the actual click value of the turrets before you use the optic in competition (or on a long-range hunt). While a scope may have listed click values of 1/4-MOA, 1/8-MOA or 0.1 Mils, the reality may be slightly different. Many scopes have actual click values that are slightly higher or lower than the value claimed by the manufacturer. The small variance adds up when you click through a wide range of elevation.
In this video, Bryan Litz of Applied Ballistics shows how to verify your true click values using a “Tall Target Test”. The idea is to start at the bottom end of a vertical line, and then click up 30 MOA or so. Multiply the number of clicked MOA by 1.047 to get the claimed value in inches. For example, at 100 yards, 30 MOA is exactly 31.41 inches. Then measure the difference in your actual point of impact. If, for example, your point of impact is 33 inches, then you are getting more than the stated MOA with each click (assuming the target is positioned at exactly 100 yards).
How to Perform the Tall Target Test
The objective of the tall target test is to insure that your scope is giving you the proper amount of adjustment. For example, when you dial 30 MOA, are you really getting 30 MOA, or are you getting 28.5 or 31.2 MOA? The only way to be sure is to verify, don’t take it for granted! Knowing your scopes true click values insures that you can accurately apply a ballistic solution. In fact, many perceived inaccuracies of long range ballistics solutions are actually caused by the scopes not applying the intended adjustment. In order to verify your scope’s true movement and calculate a correction factor, follow the steps in the Tall Target Worksheet. This worksheet takes you thru the ‘calibration process’ including measuring true range to target and actual POI shift for a given scope adjustment. The goal is to calculate a correction factor that you can apply to a ballistic solution which accounts for the tracking error of your scope. For example, if you find your scope moves 7% more than it should, then you have to apply 7% less than the ballistic solution calls for to hit your target.
NOTE: When doing this test, don’t go for the maximum possible elevation. You don’t want to max out the elevation knob, running it to the top stop. Bryan Litz explains: “It’s good to avoid the extremes of adjustment when doing the tall target test.I don’t know how much different the clicks would be at the edges, but they’re not the same.”
Should You Perform a WIDE Target Test Too?
What about testing your windage clicks the same way, with a WIDE target test? Bryan Litz says that’s not really necessary: “The wide target test isn’t as important for a couple reasons. First, you typically don’t dial nearly as much wind as you do elevation. Second, your dialed windage is a guess to begin with; a moving average that’s different for every shot. Whereas you stand to gain a lot by nailing vertical down to the click, the same is not true of windage. If there’s a 5% error in your scope’s windage tracking, you’d never know it.”
Verifying Scope Level With Tall Target Test
Bryan says: “While setting up your Tall Target Test, you should also verify that your scope level is mounted and aligned properly. This is critical to insuring that you’ll have a long range horizontal zero when you dial on a bunch of elevation for long range shots. This is a requirement for all kinds of long range shooting. Without a properly-mounted scope level (verified on a Tall Target), you really can’t guarantee your horizontal zero at long range.”
NOTE: For ‘known-distance’ competition, this is the only mandatory part of the tall target test, since slight variations in elevation click-values are not that important once you’re centered “on target” at a known distance.
When you’re out at the range, the Earth seems very stable. But it is actually a big sphere zooming through space while spinning around its axis, one complete turn every 24 hours. The rotation of the earth can create problems for extreme long-range shooters. During extended bullet flight times, the rotation of the planet causes an apparent deflection of the bullet path over very long distances. This is the ballistics manifestation of the 
Here’s a valuable web resource our readers should bookmark for easy access in the future. 
Verifying Scope Level With Tall Target Test
