June 3rd, 2017

The Wind Hack — Quick Way to Calculate Crosswind Deflection

Applied Ballistics Crosswind Estimation Wind hack G7 BC

Applied Ballistics Wind Hack

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.

Applied Ballistics Crosswind Estimation Wind hack G7 BC

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.


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.

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February 28th, 2014

New Online Ballistics Calculator from Federal Premium

Federal Premium Ballistics Online CalculatorFederal Premium has a new online Ballistics Calculator. This free program can determine the trajectory for any rifle or handgun load, and even save your ballistics solutions for future reference. This is handy if you shoot Federal ammunition, because all Federal ammo types are included in the built-in database, with BCs and velocities. That makes it very easy to get a ballistics solution for Federal factory ammo — simply enter the caliber and bullet type/weight and the solver fills in the BC and velocity for you.

Federal’s Ballistics Calculator can also be used for handloaded ammo with non-Federal components. However, you can only use a G1 BC and Federal’s solver is not as sophisticated as some others. We still recommend JBM Ballistics or the new Applied Ballistics Online Solver. These both offer both G1 and G7 and extensive databases of field-derived BCs for hundreds of bullets. The Federal Ballistics Calculator only has BC numbers for factory-made Federal ammunition.

Federal Premium Ballistics Online Calculator

Federal Premium Ballistics Online Calculator

Permalink Bullets, Brass, Ammo, New Product No 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.

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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 »
October 6th, 2010

6mm 90s & 95s — Lighter Bullets May Be Better for Mid-Range

Many shooters using the 6mmBR case or a 6BR Improved (6 BRX, Dasher), automatically assume they should be shooting the heavier 105-108gr bullet designs because these offer the “best” ballistic coefficient attainable with a bullet that can work in an 8-twist barrel.

95 grain Sierra MatchKingHowever, if you are shooting a 6BR at medium ranges, say 250 to 400 yards, you should seriously consider trying the 90-95 grain class of bullets, which includes the Berger 90gr Match Target BT, the Lapua 90gr Scenar, the Berger 95gr Match Target VLD, and the Sierra 95gr MatchKing.

First, you may find that, in your barrel, the 90-95 grainers are easier to tune in terms of seating depth, and they may offer somewhat better raw accuracy — yielding smaller groups than the heavier bullets. But remember — each gun/barrel is different.

Second, another advantage of the 90-95s is that you can fill the case fuller with the Varget/RL-15 class of powders (with appropriate throats). You can use more powder and therefore get closer to an optimal 100% case fill. With a 95gr VLD seated long we were able to get virtually 100% fill with a slow lot of Varget. Don’t try that with your 105s!

Lighter Bullets Offer More Speed in a 6BR
You’ll find that, in a standard 6mmBR rifle, you can drive the 90-95 grainers considerably faster than the 105-108 grain bullets at equivalent pressures. In an Eliseo R5 Tubegun, with Broughton 27.5″ 5C barrel, we were able to push the 95gr VLDs a full 160 fps faster than the 108s. This means that the true ballistics of the 90-95s rival that of the heavy bullets — at medium ranges.

We were able to drive the 90-grainers and the 95gr VLDs comfortably and very accurately at 3050 fps, whereas we maxed out at about 2890 fps with the 105gr and 108gr Bergers. At 300 yards, the 95gr bullet’s speed advantage compensates, in large part, for any BC shortfall compared to heavier bullets. In fact, in our rifle, the 95gr VLD actually shows less wind drift at 300 yards than either the Berger 105 Match Target BT or the Berger 108 Match Target BT. See chart.

Here’s data from JBM Ballistics, using G7 Coefficients (500′ alt, 70° temp):

LESSON: Don’t always assume that the heavier bullet has superior ballistics. You have to test, find the accuracy nodes for each bullet in your gun, and run the ballistics for the velocities you can actually achieve with good accuracy. As above, you may be surprised. In our Eliseo Tubegun, the 90-grainers shot tighter than 105s and we gave up little, if anything, in wind drift at 300 yards.

Great Accuracy from 90s and 95s in 6mmBR Tubeguns
In our Broughton-barreled Tubegun, the most accurate bullet so far has been the 90gr Lapua Scenar. In a Savage 6BR with 3-groove PacNor Barrel the Berger 95gr VLD has been ultra-accurate. But we really want to try the 95gr Sierra MK as well. Forum member Randy (aka “InfantryTrophy”) has been shooting the 95gr SMK with great success, and impressive accuracy. Here is his report: “The 95 SMK shoots great. I have not had the opportunity to shoot the 95s at 200 or 300 yards, but I can’t think of anything better to use. This is my first 5-round group fired after about 15 break-in rounds. The load is 29.5 grains of Reloder 15 with SMK 95. The gun is an Eliseo R5 with Pierce action and Broughton 27″ barrel. Shown below is a 5-shot, 100-yard group shot at 100 yards on MR31 target with iron sights, from rest.” Randy measured his group at 0.214″. It looks a bit bigger than that to us, but it is still impressive:

Permalink Bullets, Brass, Ammo, Competition 2 Comments »
March 25th, 2010

New Ballistics App for Android OS Smart-Phones

SHOOTER Android Ballistics programBryan Litz, author of Applied Ballistics for Long Range Shooting, informed us that sophisticated new ballistics software is now available for Android OS phones. While there are ballistics programs that run on iPhones, as well as programs for Palm or Windows PDAs (Personal Digital Assistants), Bryan believes that the new Ballistics App, called SHOOTER, is the first such program for Android operating system (OS) products — such as Motorola’s Droid phone and Google’s new Nexus phone.

Bryan explained: “The SHOOTER App can be found in the Google marketplace by searching for ‘Ballistics’. I became interested in this program when I got my Android phone. There are several good programs out there for iPhones and PDAs. But SHOOTER is the first program I know of for Android. In my opinion, it won’t be topped by anything else. If you have an Android smartphone, I highly recommend checking out this application. The program is easy to install and run. Outputs are available as a single-shot solution or as a table. There is a ‘Lite’ version of SHOOTER that you can download for free, and the ‘full’ version is $9.99.”

CLICK HERE for SHOOTER Android OS Ballistics Program.
CLICK HERE for SHOOTER LITE Android OS Ballistics Program.

The new “Shooter” Program for Android OS has an impressive list of features:

  • G1 and G7 BC capability, with the option to input ‘velocity banded’ BCs.
  • Angle Compensation (Up or Down Angle can be measured using the built-in inclinometer).
  • Bullet Library which includes Litz-measured “true” BCs.
  • Rifle and ammo profiles (for storing load info for all your guns).
  • Atmosphere effects (pressure, temp, and humidity).
  • Spin drift (requires bullet length and twist rate inputs).
  • Coriolis effect (works best with GPS-equipped Android phones).

Bryan revealed: “I was heavily involved in the development of this program and can vouch for the accuracy of the solution. The actual solver is very similar to the one used in my programs and in the JBM online Ballistics Program. SHOOTER’s calculations normally match my numbers and JBM’s numbers within round-off error (0.1″ at 1000 yards).”

Single-Distance Ballistics Solution Multi-Distance Ballistics Table

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