September 5th, 2019

G1 vs. G7 Ballistic Coefficient Models — What You Need to Know

G1 G7 BC drag models

Over the past 12 months, this article was one of the TOP TEN most-read Daily Bulletin features. We’re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video.

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 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.

G1 G7 Ballistic coefficients

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.

G7 BCs:
Berger 180 VLD: 0.337 lb/in²
JLK 180: 0.330 lb/in²

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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August 28th, 2019

Test Your Ballistics Knowledge with Shooting Quiz

Shoot 101 Quiz
How much of an expert are you when it comes to firearms and ballistics? Test your knowledge with this interactive test. Guns & Ammo magazine created a series of features called Shoot 101. These articles provide “how to” information about shooting, optics, and outdoor gear.

On the Guns & Ammo website, you’ll find the Shoot 101 Ballistics Quiz. The 15 questions are pretty basic, but it’s still fun to see if you get all the answers correct.

You don’t need a lot of technical knowledge. And it’s not all about flight ballistics. Roughly a third of the questions are about projectile types and bullet construction. Note, for some reason the layout doesn’t show all the possible answers at first. So, for each question, be sure to scroll down using the blue scroll bar on the right.

CLICK HERE to Go to Ballistics QUIZ Page »


Sample Ballistics Question

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August 1st, 2019

Ballistics TIP: How Altitude and Air Pressure Affect Bullet Flight

Trajectory of Bullet fired at Sea Level

Trajectory of Bullet fired at 20,000 feet

You can do your own experimental calculations using JBM Online Ballistics (free to use). Here is an extreme example, with two printouts (generated with Point Blank software), one showing bullet trajectory at sea level (0′ altitude) and one at 20,000 feet. For demonstration sake, we assigned a low 0.2 BC to the bullet, with a velocity of 3000 fps.

Suunto AltimeterOne of our readers asked “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.

Forum member Milanuk explains that the key factor is not altitude, but rather air pressure. Milanuk writes:

“In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. For example, I shoot at a couple ranges here in the Pacific Northwest. Both are at 1000′ ASL or less. I’ll need about 29-30 MOA to get from 100 yard to 1000 yards with a Berger 155gr VLD @ 2960fps. By contrast, in Raton, NM, located at 6600′ ASL, I’ll only need about 24-25 MOA to do the same. That’s a significant difference.

Note that it is the barometric pressure that really matters, not simply the nominal altitude. The barometric pressure will indicate the reduced pressure from a higher altitude, but it will also show you the pressure changes as a front moves in, etc. which can play havoc w/ your calculated come-ups. Most altimeters are simply barometers that read in feet instead of inches of mercury.”

As Milanuk states, it is NOT altitude per se, but the LOCAL barometric pressure (sometimes called “station pressure”) that is key. The two atmospheric conditions that most effect bullet flight are air temperature, and barometric pressure. Normally, humidity has a negligible effect.

It’s important to remember that the barometric pressure reported on the radio (or internet) may be stated as a sea level equivalency. So in Denver (at 6,000 feet amsl), if the local pressure is 24″, the radio will report the barometric pressure to be 30″. If you do high altitude shooting at long range, bring along a Kestrel, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.”

If you want to learn more about all aspects of External Ballistics, ExteriorBallistics.com provides a variety of useful resources. In particular, on that site, Section 3.1 of the Sierra Manual is reprinted, covering Effects of Altitude and Atmospheric Pressure on bullet flight.

Permalink Bullets, Brass, Ammo, Tech Tip 2 Comments »
December 27th, 2018

Cartridge Comparison Guide Covers 250+ Cartridges

Cartridge Comparison Guide

Cartridge Comparison GuideThe Cartridge Comparison Guide is a remarkably comprehensive 340-page, spiral-bound book. Covering over 250 cartridges, the Second Edition of the Cartridge Comparison Guide is the product of many years of labor by Andrew Chamberlain, a Utah-based hunter. Andrew says his Guide “compares every factory available cartridge from the 17 calibers up to the 50 caliber cartridges”. (Sorry, most wildcat cartridges are not covered.) Chamberlain’s Guide also compiles cartridge data from major ammunition manufacturers such as Barnes, Federal, Hornady, Norma, Nosler, Remington, Sierra, Swift, Weatherby, and Winchester. It shows the optimal velocity achieved for each bullet weight and calculates bullet energy, recoil, and powder efficiency. Large color photos illustrate handgun and rifle cartridges.

The Cartridge Comparison Guide provides data for thousands of cartridge/bullet/velocity combos. Quick reference data sheets and ballistics charts cover Trajectory, Velocity, and Energy out to 500 yards. The Cartridge Comparison Guide also offers a firearms lexicon, plus Appendices covering Cartridge Selection for Game Animals, Bullet Selection/Design, Bullet Expansion, Wound Channel Characteristics and more.

New Content in Second Edition of Cartridge Comparison Guide
The Cartridge Comparison Guide (Second Edition) costs $29.96 plus shipping and tax. CLICK HERE to visit the Online Store where you can order the 340-page book. Here’s what’s new in the Second Edition:

  • Addition of Shotgun Ammunition (Both Slug and Shot loads).
  • Momentum Calculation for all Rifle, Shotgun and Handgun loads.
  • Integration of Shotgun Slug Ammunition with Center Fire Rifle Data Tables.
  • Factory Load Summary Added (Shows manufacturers and loads produced).
  • One factory load and one hand load for every bullet weight available in each cartridge.
  • Over 90 pages of additional ballistics content (roughly 35% more than in First Edition).

Cartridge Comparison Guide

Great Resource for Hunters
One of Chamberlain’s main goals in creating the Cartridge Comparison Guide was to help hunters select the right cartridge for the job: “This started as a personal project to gather information on the more popular cartridges commonly used for hunting. I wanted to find the best all-around performing cartridge and rifle that a guy on a budget could shoot. I began comparing cartridge performance, versatility, bullet selection, powder efficiency, recoil generation vs. energy produced, standing ballistic data for different environments….”

Giant Cartridge Poster for Computer Wallpaper (1665×1080 pixels)
Here’s a great illustration of hundreds of cartridges and shotshell types. For dedicated reloaders, this would work great as desktop “wallpaper” for your computer. CLICK HERE for full-size image.

cartridge poster

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August 15th, 2018

Are You a Gun Wizard? Take the Shoot 101 Ballistics Quiz

Shoot 101 Ballistics Question Quiz BC trajectory

Shoot 101 Quiz
How much of an expert are you when it comes to firearms and ballistics? Test your knowledge with this interactive test. Vista Outdoors, parent of Savage, CCI, Federal, Bushnell, RCBS and other brands, has a media campaign called Shoot 101, which provides “how to” information about shooting, optics, and outdoor gear.

On the Shoot 101 website, you’ll find a Ballistics Quiz. The questions are pretty basic, but it’s still fun to see if you get all the answers correct.

You don’t need a lot of technical knowledge. Roughly a third of the questions are about projectile types and bullet construction. Note, on some platforms the layout doesn’t show all FOUR possible answers. So, for each question, be sure to scroll down to see all FOUR choices. REPEAT: Scroll down to see ALL answers!

CLICK HERE to Go to SHOOT 101 Ballistics QUIZ Page »

Sample Ballistics Question 1:

Shoot 101 Ballistics Question Quiz BC trajectory

Sample Ballistics Question 2:

Shoot 101 Ballistics Question Quiz BC trajectory

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June 27th, 2018

New Interactive Ballistics Calculator from Winchester

Winchester Ballistic Calculator mobile App

Winchester just unveiled a completely updated website at Winchester.com. The new, mobile-friendly website offers comprehensive information on Winchester ammunition. In addition, the upgraded Winchester website now boasts a full-featured, interactive Ballistics Calculator which runs on web browsers as well as mobile Apps. This new Ballistics Calculator offers an innovative “Shooter’s Eye View”, shown above. You can change the magnification level on the “scope”, and adjust variables (such as temp and range) using the red sliders. Try it out — it’s fascinating to see how the calculated Point of Impact moves as you adjust the sliders.

NEW Winchester Ballistic Calculator Features:

— Calculator provides precise trajectory for hundreds of cartridge types and bullet weights
— Calculator includes library of Ballistic Coefficients.
— Calculator offers visual graphs showing trajectories — with calculated point of impact as well as trajectory curve chart.
— Calculator variables include sight-in range, target range, air temperature, crosswind speed, sight height, and elevation.
— Calculator offers side-by-side comparisons among five separate rounds.
— Calculator offers detailed statistics chart for fine-tuning your shooting.
— Calculator can print handy, small Drop Chart you can attach to your rifle.

Winchester Ballistic Calculator mobile App

The Winchester Ballistic Calculator is available as a free download for iPhone and iPad through the Apple iOs app store, and for Android phones and tablets through Google Play.

Winchester Ballistic Calcultor mobile App

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February 9th, 2017

Ballistics Brain Power — Take Our Ballistics Quiz

Ballistics Quiz Bryan Litz Applied Ballistics

At the Berger SW Nationals this week in Phoenix, the nation’s top long-range shooters will try to put all their shots in the 10-Ring at 800, 900, and 1000 yards. A good foundation in ballistics is vital if you want to succeed in the long-range game.

How much do you know about BCs, Bullet Shapes, Trajectories, Wind Drift, and other things in the realm of External Ballistics? You can test your knowledge of basic Ballistics principles with this interactive quiz. The questions and answers were provided by Ballistics Guru Bryan Litz of Applied Ballistics LLC. Bryan is the author of Applied Ballistics for Long-Range Shooting and other popular resources in print, DVD, and eBook format. Have fun with our Quiz.

The Quiz contains ten (10) questions. When you complete all ten questions, you can see your results, along with the correct answers.

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March 18th, 2016

Benefits of Wind Flags for Varmint Hunting

Improve Your Hit Ratio by Using Wing Flags
It’s not unusual for varmint hunters to invest $3,000.00 in a custom rifle, pay thousands more for spotting scope and laser rangefinder, and spend countless hours loading ultra-precise ammo. Yet, when they head off to the prairie dog fields, they’ll omit an essential piece of gear that can make the difference between a hit and a miss.

We’re talking about windflags. Many casual shooters, varmint hunters, and even some “tactical” shooters disdain windflags as gadgets suited only for the accuracy-obsessed benchrest crowd. In fact, windflags are just as important for the varminter as for the benchrest competitor. You may think that you can easily notice a major wind shift. But consider this, a change from a light 2.5 mph left breeze to a 2.5 mph right is a 5 mile per hour switch. That is enough to make you miss a prairie dog even at just 200 yards.

Here’s a chart that shows the effect of a 5 mph full-value (i.e. 90-degree) wind change at various distances. The values assume a typical .250 G1 BC varmint bullet launched at 3500 fps at a 3″-wide critter (center hold).

Varmint Hunter Wind Flag

You don’t need to spend a lot of money on windflags. Even a bit of surveyors’ tape on a post is better than nothing. A simple windflag, placed at your shooting station, helps minimize the effect of cross-winds. If you align your shooting position so the breeze is at your back you can shoot with greater confidence even in high winds. Watch the way the windflag blows, and shoot at the dog mounds that are directly downwind.

Our friend Boyd Allen offers another tip: “When you go varminting, be sure to bring some kind of portable target stand. Accuracy or zero problems are much easier to diagnose and remedy if you can set up a target at 100 yards. A simple wood, A-Frame design, hinged at the top, works well, stores flat, and is easy to build.”

Windflag photo courtesy Flying Fish Fundamentals, makers of single-and dual-vane wind flags.
Permalink Hunting/Varminting, Tech Tip 6 Comments »
September 2nd, 2015

Mount Trajectory Table on Scope Cover for Easy Viewing

scope-mounted trajectory table

scope-mounted trajectory tableHere’s a great tip from Forum member Greg C. (aka “Rem40X”). Greg has created a trajectory table with windage and elevation data for various distances and wind speeds. Greg prints out a compact version of his drop chart to place on his rifle. While many shooters tape a ‘come-up’ table on their buttstock, Greg has a better solution. He tapes the trajectory table to the outside of his front flip-up scope cover. This way, when he flips up the cover, his data is displayed for easy viewing right in front.

With your ‘come-up’ table on the flip-up cover you can check your windage and elevation easily without having to move up off the rifle and roll the gun over to look at the side of the stock. Greg tells us: “Placing my trajectory table on the front scope cover has worked well for me for a couple of years and thought I’d share. It’s in plain view and not under my armpit. And the table is far enough away that my aging eyes can read it easily. To apply, just use clear tape on the front objective cover.”

Permalink Optics, Tech Tip 6 Comments »
March 2nd, 2015

Bullet Sorting — Bryan Litz Offers Smart Advice

At the 2015 Berger Southwest Nationals, Forum member Erik Cortina cornered Bryan Litz of Applied Ballistics. Erik, the F-Open winner in the 600-yard Mid-Range match, 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.

accurateshooter.com forum bryan litz berger ballistics bullets

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February 5th, 2015

Finned, Frangible Bullets Drop to Ground within 600m

Here’s an important technology for ranges concerned with over-flight risks. Regular Bulletin readers will recall that we recently warned of the dangers of bullets launched with a high trajectory. (READ Article.) With a muzzle elevation of just 5°, a conventional bullet can fly over 3000 yards, retaining enough energy to kill. General Dynamics has come up with a solution for live-fire training programs that don’t require long-range target engagements. General Dynamics’ Short Stop® ammunition launches bullets that literally drop out of the air within 600 meters. What’s the secret to the short flight? Read on…

Short Stop 5.56x45mm and 7.62x51mm Ammunition Trajectory
shortstop ammunition ammo polymer bullet short trajectory

shortstop ammunition ammo polymer bullet short trajectoryThis illustration shows the trajectories of 5.56 and 7.62 Short Stop bullets (yellow zone) compared to conventional rifle projectiles (black lines). You can see the “flight cycle” is completely different.

Short Stop ammunition employs advanced polymer/copper composite bullets with molded “fins”. The bullets sort of look like the end of a Phillips screwdriver (except the fins have a slight twist near their base). This “twisted fin” design causes the bullets to yaw, and that, in turn induces aerodynamic drag — a lot of drag. The molded bullets are also much lighter than conventional bullets (of the same caliber). The reduced weight/density gives them less momentum, so they lose velocity more readily than normal bullets. The combination of the low mass and high drag makes these bullets drop from the air within 600m or so, living up to their “Short Stop” designation.

In an interview with NRABlog.com, General Dynamics Bus. Dev. Manager Ruben Regalado explained how the Short Stop ammunition works. With this design, he says, “You can do a lot of the training you would do with a ball round with no fear of overflight. It’s the fin that does it. Due to the nature of its composition [the bullet] is lighter than the standard projectile, but the magic is in the fin.”

shortstop ammunition ammo polymer bullet short trajectory

There are many potential applications for Short Stop rounds according to NRABlog Editor Lars Dalseide: “Where do these rounds come into play? Anywhere. Anywhere there’s military training, law enforcement training, or basic target shooting taking place. And with the encroachment of communities surrounding your favorite neighborhood range, [projectiles] that drop out of the air at 600 meters means the risk of overflight is significantly reduced.” The polymer-composite bullets are also frangible, so there is less penetration of objects and less chance of ricochet.

Bryan Litz Applied Ballistics ShortStop General Dynamics“Smurf” Bullets for .50 Caliber AA Rifles
Bryan Litz of Applied Ballistics has seen ammo similar to Short Stops used in .50-caliber rifles for training purposes. Bryan tells us: “Similar rounds have been available for .50 cal for many years. We find [the spent bullets] on the range at Camp Grayling (a Michigan National Guard training facility where we hold 1000-yard matches). The .50 cal rounds use blunt plastic things (we call them ‘Smurf’ bullets) and they use them for practicing anti-aircraft shooting. Instructors put up an RC target drone and the Guardsmen shoot at it with the .50s using the short range ammunition.”

Bryan says these “short flight” bullets have an important purpose, though the applications remain limited. “These kind of projectiles are a good tool for applications where an adequate SDZ (Surface Danger Zone) cannot be secured for the range location. I just hope the application remains confined to only those places where it’s necessary, i.e. where the SDZ presents a problem. I would hate to see our bullet options be limited to something like this under the guise of ‘range safety’, where the SDZ is properly secured.”

shortstop ammunition ammo polymer bullet short trajectory

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February 1st, 2015

Over-Shooting the Berm — When a Mere 5 Degrees Can Be Deadly

In our Shooters’ Forum, there was an discussion about a range that was threatened with closure because rifle over-shoots were hitting a farm building over two miles from the firing line. One reader was skeptical of this, asking “how’s that possible — were these guys aiming at the stars?” Actually, you may be surprised. It doesn’t take much up-angle on a rifle to have a bullet land miles down-range. That’s why it’s so important that hunters and target shooters always orient their barrels in a safe direction (and angle). Shooters may not realize how much a small tilt of the barrel (above horizontal) can alter a bullet’s trajectory.

How many degrees of muzzle elevation do you think it would take to hit a barn at 3000 yards? Ten Degrees? Twenty Degrees? Actually the answer is much less — for a typical hunting cartridge, five to seven degrees of up-angle on the rifle is enough to create a trajectory that will have your bullet impacting at 3000 yards — that’s 1.7 miles away!

Five degrees isn’t much at all. Look at the diagram below. The angle actually displayed for the up-tilted rifle is a true 5.07 degrees (above horizontal). Using JBM Ballistics, we calculated 5.07° as the angle that would produce a 3000-yard impact with a 185gr .30-caliber bullet launched at 2850 fps MV. That would be a moderate “book load” for a .300 Win Mag deer rifle.

Gun Angle long range

Here’s how we derived the angle value. Using Litz-derived BCs for a 185gr Berger Hunting VLD launched at 2850 fps, the drop at 3000 yards is 304.1 MOA (Minutes of Angle), assuming a 100-yard zero. This was calculated using a G7 BC with the JBM Ballistics Program. There are 60 MOA for each 1 degree of Angle. Thus, 304.1 MOA equals 5.068 degrees. So, that means that if you tilt up your muzzle just slightly over five degrees, your 185gr bullet (2850 fps MV) will impact 3000 yards down-range.

Gun Angle long range

Figuring Trajectories with Different Bullets and MVs
If the bullet travels slower, or if you shoot a bullet with a lower BC, the angle elevation required for a 3000-yard impact goes up, but the principle is the same. Let’s say you have a 168gr HPBT MatchKing launched at 2750 fps MV from a .308 Winchester. (That’s a typical tactical load.) With a 100-yard zero, the total drop is 440.1 MOA, or 7.335 degrees. That’s more up-tilt than our example above, but seven degrees is still not that much, when you consider how a rifle might be handled during a negligent discharge. Think about a hunter getting into position for a prone shot. If careless, he could easily touch off the trigger with a muzzle up-angle of 10 degrees or more. Even when shooting from the bench, there is the possibility of discharging a rifle before the gun is leveled, sending the shot over the berm and, potentially, thousands of yards down-range.

Hopefully this article has shown folks that a very small amount of barrel elevation can make a huge difference in your bullet’s trajectory, and where it eventually lands. Nobody wants to put holes in a distant neighbor’s house, or worse yet, have the shot cause injury. Let’s go back to our original example of a 185gr bullet with a MV of 2850 fps. According to JBM, this projectile will still be traveling 687 fps at 3000 yards, with 193.7 ft/lbs of retained energy at that distance. That’s more than enough energy to be deadly.

Permalink Shooting Skills, Tech Tip 13 Comments »
August 1st, 2013

Updated URLs for JBM Online Ballistics Program

laminated come-up range cardThe web-based JBM Ballistics Program is one of the most sophisticated and accurate ballistics calculators available — and it’s free. The latest version of the JBM Trajectory Calculator includes field-test-derived actual G7 BCs, as well as bullet drag data from Lapua’s Doppler radar testing. You can also change weather variables, and generate come-up tables for distances out to 3000 yards.

Whenever we have web access, the JBM program is our “go-to” resource for dependable ballistics calculations. In our experience, with most bullets, if you input all the correct variables for the JBM program, it should get you within 1/2 moa (2 clicks), at 600 yards.

New URLs for JBM Ballistics Calculators
With the release of the latest version of the JBM program, some URLs for the calculations pages have changed. You may want to update your bookmarks with the following web addresses:

JBM Calculations Entry Page: www.jbmballistics.com/ballistics/calculators/calculators.shtml.

JBM Advanced Trajectory Calculator: www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi.

JBM Simple Trajectory Calculator: www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi.

JBM Trajectory Cards (Come-up Table): http://www.jbmballistics.com/cgi-bin/jbmcard-5.1.cgi.

Permalink News, Reloading 4 Comments »
September 22nd, 2012

New Litz Book: Accuracy and Precision for Long Range Shooting

Litz Accuracy Precision Shooting BookLitz Accuracy Precision Shooting BookBryan Litz, chief Ballistician for Berger Bullets (and a trained rocket scientist) has authored an impressive new book: Accuracy and Precision for Long Range Shooting. Bryan’s new book is a companion to his successful treatise, Applied Ballistics for Long-Range Shooting. Now in its Second Edition, Litz’s Applied Ballistics book has become the “go-to” Ballistics book for precision shooters worldwide.

While Bryan’s first book covers the science of ballistics and trajectory calculation, his new book examines practical issues involved in long-range accuracy. Bryan explains: “In a nutshell, this book focuses on the uncertainties of practical shooting which affect hit percentage on various size targets. In other words, classic ballistics teaches you how to calculate windage and elevation corrections. This book will help you understand what your chances are of hitting a target under certain conditions, and how to improve those chances through training and design.

Practical Examples
Does a low ES/SD really make a difference at long range? Absolutely. In Chapter 6, you can see that reducing muzzle velocity variation from 20 fps Standard Deviation (SD) to 10 fps SD improves hit percentage on a 5″ circle at 500 yards from 83% to 93%.

Ever wonder how much spin drift, Coriolis affect, or using G1 vs. G7 BC’s affect your chances of hitting a target? In Chapter 10 for example, you’ll learn that ignoring spin drift in ballistic calculations reduces hit percentage on a 10″ target from 21% to 15% at 900 yards for a specified environment and cartridge.

The new book is divided into three main sections.
Litz Accuracy Precision Shooting Book
Part 1 focuses on Precision, which explores how hit percentage is related group size. Litz explains the variable that affect group size: muzzle velocity variation, range estimation error, wind estimation error, and inherent rifle precision

Part 2 focuses on Accuracy, which is how well the group is centered around the aim-point. Topics include: leveling your sights, trajectory modeling and secondary effects, calibrating ballistic solutions, and live fire verification.

Part 3 focuses on Weapon Employment Zone (WEZ) analysis. WEZ evaluates firearm effectiveness in terms of hit percentage. The author applies WEZ in the contexts of score shooting, varmint and big game hunting, and tactical shooting. WEZ is also used to compare hit percentage for the 300 Win Mag vs. .338 Lapua Mag.

Litz Accuracy Precision Shooting Book


Book is 300-page, Hard-Cover Format
Accuracy and Precision for Long Range Shooting is a 6″x9″ hardcover book with 300 pages, and retails for $34.95. The book is currently at the printers, and should begin shipping by October 15, 2012. In the mean time, you can pre-order and save $5 off the regular $34.95 retail price.

CLICK HERE to Pre-Order Litz Book or Get More INFO.
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May 18th, 2011

JBM-Powered Ballistics Software for Apple iPads

iPad Ballistics softwareA dedicated iPad version of Ballistic (‘Ballistic’ App), a full-featured ballistics calculator for the iPhone, is available for the growing numbers of iPad users. As with the iPhone version, ‘Ballistic’ App for the iPad is “powered by JBM Ballistics” so it offers very precise solutions — typically, at 600 yards, JBM will get you within two or three clicks, provided you have good bullet BC data and reliable MV from your chronograph.

The ‘Ballistic’ App for the iPhone and iPad features a library of over 3,100 projectiles; the library includes the latest 2010 commercial data and G7 military coefficients from Aberdeen Proving Grounds. Along with calculating bullet trajectories, this software has many extra features. There are several different target cards so you can input shot placement and scoring is calculated automatically. There is also a range log (for recording shooting sessions), a mildot and MOA range estimator, and a convenient load database for storing your reloading recipes.

Special features in the iPad edition of ‘Ballistic’ App include: fully integrated split-screen ballistics, favorites, and range log; full-screen, hi-resolution charts; ballistics calculations update automatically as you edit; larger target sizes in range log; and screens can rotate. The iPad Ballistic App (release 2.3.7) costs $19.99. The standard version for iPhone and iTouch units, costs $9.99. To learn more about this software, visit ballistic.zdziarski.com.

Permalink Bullets, Brass, Ammo, New Product 2 Comments »
December 14th, 2009

MOBALL Deployable Ballistics Computer from Bryan Litz

There are a variety of ballistics programs that can be used with handheld PDAs, and even Apple iPhones. But Bryan Litz, author of the new Applied Ballistics for Long Range Shooting book, has come up with something bigger and better. Employing the powerful Texas Instruments (TI) Voyage 200 graphing calculator, Bryan has created a Mobile Ballistics Solution (MOBALL) that is more sophisticated (and accurate) than typical PDA-based programs.

Litz Moball Ballistics Calculator
MOBALL includes TI graphing calculator and ballistics software. Kestrel windmeter NOT included.

Bryan tells us: “The Mobile Ballistics Computer (MOBALL) was created for one purpose: to provide shooters with the most accurate and complete ballistic firing solution possible for application in the field.” MOBALL runs on a TI graphing calculator — a sturdy, stand-alone, non-network device. That means you don’t need long-term cell phone contracts, expensive data plans, or weekly OS “updates” and patches. The TI also delivers long run-time on ordinary AAA batteries. That’s a big advantage over most laptop computers, which run out of “juice” after only 4-5 hours in the field.

According to Bryan, what sets MOBALL apart from other “deployable” ballistics calculators is that: “MOBALL provides a complete ballistic solution, with the ability to account for every major and minor variable affecting a bullets trajectory. In addition to the standard variables like atmospherics, uphill/downhill angles and wind, MOBALL also has the ability to account for more subtle ballistic effects like spin drift, Coriolis effect, and multiple winds in up to 3 zones.”

Importantly, Bryan’s MOBALL device can employ Ballistic Coefficients (BCs) referenced to the G7 standard. Compared to the older G1 BC model, the G7 BC standard better matches the characterics of the long, boat-tail bullets actually used by long-range shooters. Trajectories calculated using the G7 BC are more accurate for long-range bullets because the G7 BC doesn’t vary with velocity like the conventional G1 BC.

G1 BCG1 BC

The difference between G1 and G7 BCs is explained online in the Berger Blog article A Better Ballistic Coefficient. The subject is also discussed in detail in Chapter 2 of Bryan’s Applied Ballistics book.

Litz Moball Ballistics CalculatorAt $290.00, MOBALL isn’t the least expensive option for a mobile ballistics device, but that price includes the TI Voyage 200 graphing calculator, worth $180.00 by itself. Bryan adds: “As already mentioned, the feature set is extensive, and the software is much more sophisticated than most ballistics programs designed for PDAs. The solution is VERY accurate (CLICK to download MOBALL Accuracy Report). Also, the TI Voyage 200 is an impressive device itself, capable of solving advanced engineering and math problems. If you’re a high school/college student, engineer, etc, the TI Voyage 200 can be used for many school and work tasks unrelated to ballistics.”

Save $20 on MOBALL and Ballistics Book Combo
As a special Holiday Offer valid through December 31, 2009, you can save money when purchasing MOBALL and Bryan’s Applied Ballistics book together. The book and MOBALL unit are being offered as a Holiday Combo Set for $309.95. That’s a $20 savings over the $329.95 cost of purchasing both book and MOBALL unit separately.

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June 24th, 2009

Lapua Offers Free Advanced Ballistics Software

Lapua has used sophisticated Doppler radar to calculate the actual air drag of its bullets throughout the course of bullet flight. Drag coefficients derived from these continuous field measurements make it possible to calculate bullets’ trajectories with great precision. By using Doppler-radar derived drag coefficients, trajectories can be predicted much more accurately than when using the simplified one-number BCs provided by most other bullet-makers.

To enable shooters to calculate trajectories (with the Doppler bullet data) more effectively, Lapua now offers a FREE special edition of QuickTarget Unlimited (QTU) software tailored for Lapua bullets. QTU is a very sophisticated program that allows you to choose among 12 different drag models. QTU also allows you to compensate for rifle firing angle, rifle cant, wind speed, atmospheric pressure, temperature, and humidity.

Lapua QuickTarget

Using this free software, you can calculate the trajectories of Lapua bullets to a great degree of certainty. With the QTU Program, as starting values, you need only bullet type and muzzle velocity (add windspeeds if known). The software will calculate bullet drop, velocity and energy as a function of distance and flight time. Complete QTU instructions are in the QTU Manual.

CLICK HERE to download QTU Software Manual. (Read the manual. QTU is complex with many variables and uses metric values by default. The manual explains how to set everything for yards and MOA, and how to input data for wind, temperature, rifle angle and other variables.)

How to Get the Software
To get the FREE QuickTarget Lapua Edition software, first go to the Lapua Ballistics Start Page. On that page, click the “Register” link. Fill in ALL the required info (user name, password, email etc.), and hit the “Create Account” button. Validation: Lapua will send a message to the email account you listed. Open that email and click the internal link to verify that you have an active, valid email account.

OK, now go back to the Ballistics Start Page. Fill in your user name and password, and click the “Login” button. A new page should open with the heading: “About QuickTarget Unlimited (QTU) Lapua Edition”. OK, now move your mouse pointer left and click on the words “Download Lapua Edition”. Now a new page will open.

Almost done. Scroll down and you’ll see a blue “Download Now” button at the bottom. Click that, then click “Agree” on the software license screen that comes next. After you click “Agree” a new page appears showing: “QuickTarget Unlimited Lapua Edition”.

Lapua QuickTarget

Click the link for “qtulapua.zip” and a 6.1 megabyte .zip archive file will be downloaded to your computer. Open that .zip file and click the “SETUP.EXE” file to install the software.

Permalink - Articles, Bullets, Brass, Ammo, New Product 6 Comments »
April 16th, 2009

Versatile Point Blank Ballistics Software is FREE

The HuntingNut.com website offers Point Blank Ballistics and Reloading software free of charge. That’s right, the program is absolutely free, forever — not just for a trial period. We use Point Blank all the time, not just to calculate come-ups and windage for our rifles, but also to compare ballistics among various chamberings, or to compare different bullets. With Point Blank it is easy to just change your bullet BC value and instantly see the effect on windage and drop. Point Blank will even calculate muzzle energy and recoil force. Point Blank will also hold all your reloading info in a built-in database. You enter the caliber (chambering), bullet, powder, velocity, and other important variables. Then you can quickly access hundreds of different load combinations.

CLICK HERE TO download PointBlank Reloading & Ballistics Software v2.0 ZIP Archive.

(Note: this 1.13mb file is for Windows computers; you need WinZip or other program to unzip the file archive.)

You can even use Point Blank to plot your shots on a test target. This way you can easily compare the accuracy of different “recipes” during load development. You can record up to 10 shots per target.

Calculate Recoil, Muzzle Energy, Knock-Out Power
Point Blank has many other useful functions. Click on the “Misc Functions” tab, and you’ll find the program will calculate recoil and muzzle energy. If you clock bullet speed at both the muzzle and a 100-yard target, the program will also calculate actual bullet Balllistic Coefficient. For hunters, the program calculates Taylor Knock-Out values, and the program even provides handy English/Metric unit conversions.

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February 28th, 2009

Lapua Offers Radar-Tested Drag Data for Lapua Bullets

Lapua bullets BCThe Ballistic Coefficient (BC) of a bullet is an index number used to describe the bullet’s aerodynamic drag relative to a reference standard. While bullet manufacturers commonly include BCs in their product descriptions, often times those numbers are merely a mathematical calculation, rather than the result of actual testing. Also, since the true drag of a bullet changes over the course of its trajectory, using a single BC is a fairly primitive way to predict how that bullet will actually perform over a long distance.

Lapua is now using Doppler radar to provide a more sophisticated model of bullet flight. Lapua has issued drag coefficients for its bullets based on radar testing. Importantly, Lapua didn’t just calculate drag coefficients off bullet blueprints. Instead, Lapua used radar to measure bullet velocities at various points along the bullet flight path (trajectory). This provides Cd (Coefficient of Drag) values that can be used with advanced ballistic software such as QuickTARGET to calculate trajectories with great reliability and precision.

Lapua bullets BC

Lapua’s engineers explain: “With our Cd-data measured by continuous Doppler radar measurements you can calculate the trajectory of your bullet much more accurately than using the simplified one-number BC. Typically-used simple ballistic coefficient (BC) describes only ballistic performance of the bullet compared to old standard ‘G1′ bullet. Ballistic Coefficient is essentially a measure of drag force compared to G1 projectile. The higher the BC value, the less drag and better ballistic performance.

The BC changes during a projectile‘s flight and stated BCs are always averages for particular velocity ranges. Knowing how a BC was established is almost as important as knowing the stated BC value itself. For the precise establishment of bullet trajectory, Doppler radar-measurements are required. The normal shooter however, has no access to such expensive professional measurement devices.

The radar-measured Cd factor describes the aerodynamic drag at particular points of trajectory. A Cd table (see above) shows this factor as a function of velocity (Mach number). Special software is required (e.g. Quick Target Unlimited) to utilize this data to [generate a] ballistic table. During the Doppler radar measurements the complete location information versus time is recorded.”

Long-Range Tests Show Lapua’s Bullet Drag Models Work Well
One of our sources has been working with Lapua’s radar-derived ballistic data for over a year. His task was to see how calculated trajectories using Lapua’s stated Cd values for particular bullets compared to observed bullet flights at long range. Using the data for the Lapua 250gr Scenar, this tester found the predicted trajectory “dead on to 1600 meters (about a mile) and only a few click off [at] 2000 meter (1.25 mile) distances”.

Bullet Ballistic Info for Download

CLICK HERE for explanation of Doppler-derived Cd with sample charts.

CLICK HERE for Cd-data for Lapua bullets.

Permalink Bullets, Brass, Ammo, Tech Tip 7 Comments »