August 10th, 2017

Is Bullet B.C. Important When Hunting? (Answer: It Depends)

Sierra Bullets Deer Hunting BC Ballistic Coefficient bullet
Game image courtesy OutdoorNebraska.gov/deer.

Written by Sierra Bullets Ballistic Technician Paul Box
Judging by the calls I’ve had through the years, I think some shooters might be placing too much importance on Ballistic Coefficient (B.C.). The best example of this comes from a call I had one day. This shooter called wanting the ballistic coefficient of one of our Sierra bullets. After I told him he seemed a little disappointed, so I ask him what his application was. Long range target, deer hunting in the woods? Talk to me.

As it turned out, he hunted deer in open timber. He very rarely shot beyond 100 yards. I pointed out to him that, under 200 yards, B.C. has little impact. Let’s compare a couple of bullets.

Let’s look at the trajectory of a couple of bullets and see how they compare. The .30 caliber 180 grain Round Nose #2170 RN and the 180 grain Spitzer Boat Tail #2160 SBT. The round nose has a B.C. of .240, while the SBT is .501. Starting both bullets out of the muzzle at 2700 FPS [with a 100-yard ZERO], at 200 yards the #2170 RN impacts 4.46″ low while the #2160 SBT impacts 3.88″ low. That’s a difference of only 0.58″ in spite of a huge difference in Ballistic Coefficient. If we compare out at 500 yards, then we have a [significant drop variance] of 14.27″ between these two bullets. [Editor: That difference could mean a miss at 500 yards.]

Distance to Your Prey is the Key Consideration
In a hunting situation, under 200 yards, having a difference of only .58” isn’t going to make or break us. But when elk hunting in wide open spaces it could mean everything.

The next time you’re choosing a bullet, give some thought about the distances you will be shooting. Sometimes B.C. isn’t everything. If you have any questions, please give the Sierra Bullets technicians a call at 800-233-8799.

sierra bullets ballistic coefficient hunting BC bullet logo customer support

Permalink Bullets, Brass, Ammo, Hunting/Varminting No Comments »
March 22nd, 2017

Chronograph Testing — Tips from the USAMU

USAMU Marksmanship Unit Velocity Chronograph Testing Sample Sizes

Each Wednesday, the U.S. Army Marksmanship Unit publishes a reloading “how-to” article on the USAMU Facebook page. This past week’s “Handloading Hump Day” article, the latest in a 7-part series, relates to chronograph testing and statistical samples. We highly recommend you read this article, which offers some important tips that can benefit any hand-loader. Visit the USAMU Facebook page next Wednesday for the next installment.

Chronograph Testing — Set-Up, Sample Sizes, and Velocity Factors

Initial Chronograph Setup
A chronograph is an instrument designed to measure bullet velocity. Typically, the bullet casts a shadow as it passes over two electronic sensors placed a given distance apart. The first screen is the “start” screen, and it triggers an internal, high-speed counter. As the bullet passes the second, or “stop” screen, the counter is stopped. Then, appropriate math of time vs. distance traveled reveals the bullet’s velocity. Most home chronographs use either 2- or 4-foot spacing between sensors. Longer spacing can add some accuracy to the system, but with high-quality chronographs, 4-foot spacing is certainly adequate.

Laboratory chronographs usually have six feet or more between sensors. Depending upon the make and model of ones chronograph, it should come with instructions on how far the “start” screen should be placed from one’s muzzle. Other details include adequate light (indoors or outdoors), light diffusers over the sensors as needed, and protecting the start screen from blast and debris such as shotgun wads, etc. When assembling a sky-screen system, the spacing between sensors must be extremely accurate to allow correct velocity readings.

Statistics: Group Sizes, Distances and Sample Sizes
How many groups should we fire, and how many shots per group? These questions are matters of judgment, to a degree. First, to best assess how ones ammunition will perform in competition, it should be test-fired at the actual distance for which it will be used. [That means] 600-yard or 1000-yard ammo should be tested at 600 and 1000 yards, respectively, if possible. It is possible to work up very accurate ammunition at 100 or 200 yards that does not perform well as ranges increase. Sometimes, a change in powder type can correct this and produce a load that really shines at longer range.

The number of shots fired per group should be realistic for the course of fire. That is, if one will be firing 10-shot strings in competition then final accuracy testing, at least, should involve 10-shot strings. These will reflect the rifles’ true capability. Knowing this will help the shooter better decide in competition whether a shot requires a sight adjustment, or if it merely struck within the normal accuracy radius of his rifle.

How many groups are needed for a valid test? Here, much depends on the precision with which one can gather the accuracy data. If shooting from a machine rest in good weather conditions, two or three 10-shot groups at full distance may be very adequate. If it’s windy, the rifle or ammunition are marginal, or the shooter is not confident in his ability to consistently fire every shot accurately, then a few more groups may give a better picture of the rifle’s true average.

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October 19th, 2016

Lapua Releases FREE Advanced 6DOF Ballistics Mobile APP

Lapua Ballistics App 6DOF degrees of Freedom solver doppler radar bullet BC Apple iOS Android OS mobile smartphone iphone

Lapua, maker of premium brass, bullets, and loaded ammo, has released a new, state-of-the-art Ballistics program that runs on smartphones and mobile devices. The all-new Lapua Ballistics Mobile App is the first mobile ballistics app utilizing the 6DOF calculation model. 6DOF refers to “Six Degrees of Freedom”, referring to the multiple variables the software calculates. As explained below, a 6DOF solver can account for 3 components of movement PLUS 3 components of rotation. Of course, as with other ballistics software, the Lapua Mobile App looks at Bullet BC, velocity, and cross-wind effects. This software can also account for subtle, extreme long range factors such as the Coriolis Effect.

Lapua Ballistics App 6DOF degrees of Freedom solver doppler radar bullet BC Apple iOS Android OS mobile smartphone iphone


CLICK HERE for FREE 28-page Ballistics App USER GUIDE

Notably, the new Lapua Ballistics App includes a library of up-to-date bullet profiles based on extensive field tests with Doppler Radar. Having an ultra-sophisticated 6DOF solver combined with Doppler Radar data makes the Lapua Mobile App one of the most accurate ballistics Apps on the market. Lapua Ballistics offers the latest, Doppler-proven Lapua cartridge and bullet data for you to combine with your firearm and local weather information. The App also includes the option to define custom bullets.

Lapua Ballistics App 6DOF degrees of Freedom solver doppler radar bullet BC Apple iOS Android OS mobile smartphone iphone

The Lapua Ballistics App is available for Android and iOS smart phones and mobile devices free of charge. For more info, visit www.lapua.com/lapuaballisticsapp.

Lapua Ballistics App 6DOF degrees of Freedom solver doppler radar bullet BC Apple iOS Android OS mobile smartphone iphone

6DOF, the most accurate calculation method. Lapua cartridge / bullet information. Distance, wind speed and angle. outputs numerical, reticle, table and graph views, metric and imperial values. Set Point Blank-range to different sight-in distances and impact windows. Define custom bullets ( BC G1 or G7 and Siacci method), Pre-set max 4 powder temperature.Sight-in-POI, Coriolis calculation

Permalink Bullets, Brass, Ammo, New Product, Tech Tip No Comments »
August 19th, 2016

New Hornady Ballistics Calculator Uses Doppler Radar Bullet Data

Hornady Ballistics Calculator 4DOF Doppler Vertical Jump Spin Drift Angle of Attack

Here’s a significant new addition to our knowledge base for Long-Range shooting. Hornady has released a new Ballistics Calculator that employs bullet profiles derived from Doppler radar testing and 3D projectile modeling. Hornady’s Patent Pending 4DOF™ Ballistic Calculator provides trajectory solutions based on projectile Drag Coefficient (not static G1/G7 ballistic coefficients) along with the exact physical modeling of projectiles and their mass and aerodynamic properties. This new 4DOF (Four Degrees of Freedom) calculator also accounts for spin drift and the subtle VERTICAL effects of crosswinds.


We strongly recommend you watch this video from start to finish. In greater detail than is possible here, this video explains how the 4DOF System works, and why it is more sophisticated than other commercially-offered Ballistics calculators. There’s a LOT going on here…

Aerodynamic Jump from Crosswind Calculated
According to Hornady, the 4DOF Ballistics Calculator “is the first publicly-available program that will correctly calculate the vertical shift a bullet experiences as it encounters a crosswind.” This effect is called aerodynamic jump. The use of radar-derived drag profiles, correct projectile dynamics, aerodynamic jump, and spin drift enable the Hornady® 4DOF™ ballistic calculator to provide very sophisticated solutions. Hornady says its 4DOF solver is “the most accurate commercially available trajectory program … even at extreme ranges.”

“Current ballistic calculators provide three degrees of freedom in their approach — windage, elevation, and range — but treat the projectile as an inanimate lump flying through the air,” said Dave Emary, Hornady Chief Ballistician. “This program incorporates the projectile’s movement in the standard three degrees but also adds its movement about its center of gravity and subsequent angle relative to its line of flight, which is the fourth degree of freedom.”

Using Doppler radar, Hornady engineers have calculated exact drag versus velocity curves for each bullet in the 4DOF™ calculator library. This means the 4DOF™ calculator should provicde more precise long range solutions than calulators that rely on simple BC numbers or drag curves based with limited data collection points. Emary adds: “The Hornady 4DOF also accurately calculates angled shots by accounting for important conditions that [other ballistic] programs overlook.”

“This calculator doesn’t utilize BCs (Ballistic Coefficients) like other calculators,” added Jayden Quinlan, Hornady Ballistics Engineer. “Why compare the flight of your bullet to a standard G1 or G7 projectile when you can use your own projectile as the standard?” That makes sense, but users must remember that Hornady’s 4DOF projectile “library” includes mostly Hornady-made bullets. However, in addition to Hornady bullets, the 4DOF Calculator currently does list seven Berger projectiles, six Sierra projectiles, and one Lapua bullet type. For example, Sierra’s new 183gr 7mm MatchKing is listed, as is Berger’s 105gr 6mm Hybrid.

This Video Explains How to Use Hornady’s New 4DOF Ballistics Calculator

Hornady Ballistics Calculator 4DOF Doppler Vertical Jump Spin Drift Angle of Attack

Using the 4DOF™ Ballistic Calculator:
The Hornady 4DOF Ballistic Calculator provides trajectory solutions based on projectile Drag Coefficient (not ballistic coefficients) along with exact physical modeling of the projectile and its mass and aerodynamic properties. Additionally, it calculates the vertical shift a bullet experiences as it encounters a crosswind, i.e. “aerodynamic jump”. The use of drag coefficients, projectile dynamics, aerodynamic jump, and spin drift enable the 4DOF Ballistic Calculator to accurately measure trajectories even at extreme ranges. It is ideal for both long range and moderate distances and is available for the low-drag precision bullets listed in the drop down menu of the calculator. For calculating trajectories of traditional hunting and varmint bullets using BCs (ballistic coefficients), you can use Hornady’s Standard Ballistics Calculator.

Hornady Ballistics Calculator 4DOF Doppler Vertical Jump Spin Drift Angle of Attack

Permalink - Videos, Bullets, Brass, Ammo, Tech Tip 2 Comments »
December 3rd, 2015

Get Info for 3900 Bullets in FREE Online Database

ShooterForum Bullet Database

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 coverage of the Bullet Database is amazing. Manufacturers in the database include: A-Square, Barnaul, Barnes, Berger, Brenneke, Calhoon, CDP, CheyTac, ColoradoBonded, CT, DAG, David Tubb, Delsing, DEWC, DKT, DTK, DYN, Federal, Fiocchi, FMJ, FN, Fortek, FP, Freedom, Frontier, GECO, Gian-Marchet, GPA, GS-Custom, H&N, Hawk, HeviShot, Hirtenberger, Hornady, HP, Igman, IMI, IMI-Samson, Impala, JDJ, JLK, Klimovsk, Lapua, LEADEx, LEE, Lehigh, LIMA, LostRiver, LYM, MEN, Mil, Norinco, Norma, NorthFork, Nosler, PMC, PMP, Powell, PrviPartizan, Rainier, RCBS, Reichenberg, Remington, RN, RNFP, RUAG, RWS, Sako, Sellier-Bellot, Shilen, Sierra, Sinterfire, Speer, Stoklossa, SWC, Swift, Swiss, The Gun Haus, TMJ, WestCoast, Winchester, WM-Bullets and Woodleigh.

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.”

Permalink Bullets, Brass, Ammo, Reloading 4 Comments »
October 28th, 2015

New Hornady ELD Bullets with Heat-Resistant Tips

Hornady ELD Low Drag Heat Resistant Bullet Tip Match Bullets Hunting

In 2016, Hornady will introduce new hunting and match bullets with high-tech, heat resistant tips. Hornady developed the new “Heat Shield” bullet tips after Doppler Radar testing showed that the Ballistic Coefficients (BCs) of old-style tipped bullets were degrading in flight in an unexplained manner. Hornady’s engineers theorized that the old-style plastic bullet tips were deforming in flight due to heat and pressure. Hornady claims this problem occurred with high-BC (0.5+ G1) tipped bullets from a variety of manufacturers. Hornady’s testers believed that, after 150 yards or so, the tips on high-BC bullets were actually melting at the front. That enlarged the meplat, resulting in increased drag.*

Consequently, Hornady developed a new type of bullet tip made from a heat-resistant polymer. Further long-range Doppler Radar testing seemingly confirmed that bullets equipped with the new tips did not suffer from the BC loss previously found. This allowed the bullets to maintain a higher, more consistent BC during the entire trajectory. The end result is a bullet with reduced vertical dispersion at long range (or so Hornady claims).

New Hornady ELD-X Hunting Bullets
For 2016, Hornady will bring out two lines of projectiles using the new tips. The first line of bullets, designed for hunting, will be called ELD-X, standing for “Extreme Low Drag eXpanding”. These feature dark red, translucent, heat-resistant tips. With interlock-style internal construction, these hunting projectiles are designed to yield deep penetration and excellent weight retention. Hornady will offer seven different ELD-X bullet types, ranging in weight from 143 grains (6.5mm) to 220 grains (.30 Cal):

6.5mm, 143 grain (G1 .620 / G7 .310)
7mm, 162 grain (G1 .613 / G7 .308)
7mm, 175 grain (G1 .660 / G7 .330)

.308, 178 grain (G1 .535 / G7 .271)*
.308, 200 grain (G1 .626 / G7 .315)
.308, 212 grain (G1 .673 / G7 .336)
.308, 220 grain (G1 .650 / G7 .325)

NOTE: We don’t know if the stated BC values are based on drag models or actual range testing. These new ELD-X hunting bullets will be loaded into a new line of Precision Hunter Ammo for a variety of popular hunting cartridges.

Hornady ELD Low Drag Heat Resistant Bullet Tip Match Bullets Hunting

New Hornady ELD Match Bullets
Along with its new hunting bullets, Hornady is coming out with a line of ELD Match bullets as well. Hornady’s engineers say the new molded “Heat Shield Tip” should be a boon to competitive shooters: “You can’t point up that copper [tip] as consistently as you can mold a plastic tip. With the ELD Match line, and the Heat Shield Tip technology… we now have a perfected meplat. These bullets allow you to shoot groups with less vertical deviation, or less vertical stringing, because the bullets are exact in their drag [factor].” There are currently four bullets in the ELD Match line:

.264 Caliber (6.5mm), 140 grain (G1 .610 / G7 .305)
.284 Caliber (7mm), 162 grain (G1 .627 / G7 .313)
.308 Caliber (7.62mm), 208 grain (G1 .670 / G7 .335)
.338 Caliber (8.6 mm), 285 grain (G1 .789)

Hornady will offer factory ammunition loaded with ELD Match bullets, starting with 6.5 Creedmoor ammo loaded with the 140gr ELD, and .338 Lapua Magnum ammo loaded with the 285gr ELD.

Better Tips Make a Difference — But other Factors Are Important
Hornady claims that its new Heat Shield Tips are more uniform than the meplats on conventional jacketed, hollow-point bullets. This, Hornady says, should provide greater bullet-to-bullet BC consistency than is possible with conventional, non-tipped bullets.

We have heard such claims before. Plastic tips are good, so long as they are inserted perfectly in the bullet. But sometimes they are crooked (off-axis) — we’ve seen that with various brands of tipped projectiles. Other factors will affect bullet performance as well, such as bullet weight, bullet diameter, and bullet bearing surface length. Even with perfectly uniform bullet tips, if bullet weights or diameters are inconsistent across a sample, you can still have accuracy issues (and pressure-related velocity variances). Likewise, if the bearing surface lengths vary considerably from one bullet to the next, this can increase velocity spread and otherwise have a deleterious effect on accuracy.

So, overall, we think Hornady has probably engineered a better bullet tip, which is a good thing. On the other hand there are many other factors (beyond tip uniformity) involved in long-range bullet performance. It will be interesting to test the new ELD Match bullets to see how they compare with the best hollow point jacketed bullets from other manufacturers.

MORE TECHNICAL DETAILS

* Hornady’s Chief Ballistician Dave Emary authored a technical report based on the Doppler Radar testing of a variety of tipped Bullets. CLICK HERE for Emary Report. Here are some of the report’s key observations and conclusions:

After early testing of prototype bullets it was observed that all currently manufactured tipped projectiles’ drag curves were convex, not concave and that abnormally low ballistic coefficients were being observed over long ranges. The drag was rapidly increasing at high velocities.

At this point extensive testing was done with all types of commercially-available tipped projectiles. They all exhibited this behavior to a greater or lesser extent depending on their ballistic coefficient and launch velocity. Most projectiles exhibited BCs relatively close to published values for 150 to 200 yards of flight. Beyond these distances they all showed BCs substantially below published values.

It was obvious that something was changing in the tipped projectiles to cause a rapid increase in drag at higher velocities. The drag increases were most noticeable from 100 to about 500 yards. Drag increases stopped at velocities below approximately 2,100 fps. This behavior was not observed with hollow point or exposed lead (spitzer) style designs. The problem magnified as the velocity was increased. The problem was worse for heavier, higher-BC projectiles that maintained higher velocities longer. After some consideration the answer was obvious and one that several people had wondered about for some time but had no way to prove their thoughts.

The tip of a bullet at 3,000 fps will see temperatures as high as 850 degrees F and decreasing as
the bullet slows down. These temperatures on the tip were a known fact. What wasn’t known was how long it would take at these peak and decreasing temperatures for the polymer tips to begin showing effects, if at all. As it turns out it is within the first 100 yards of flight. Currently-used polymers in projectile tips begin to have properties like rubber at approximately -65 to 50 degrees F and will melt at 300 to 350 degrees F, depending on the exact polymer.

All current polymer-tipped projectiles have tips that are at best softening and deforming in flight and under many circumstances melting and badly deforming. To cut through a lot of technical discussion the problem becomes worse at higher ambient air temperatures (summer) and higher launch velocities. Projectiles that have a high BC and retain velocity well see higher stagnation temperatures for longer lengths of time and have greater degradation of the tip. Simply put it is a heat capacity problem –temperature times time. This makes BCs for current tipped projectiles a rough average over some distance, dependent on atmospheric conditions and muzzle velocity, and does not allow the accurate prediction of downrange ballistics much beyond 400 yards.

Permalink Bullets, Brass, Ammo, New Product 10 Comments »
October 22nd, 2015

Berger Updates Bullet BC Data and Recommended Twist Rates

Berger BC Ballistics Coefficient Barrel Twist Rate  Updates

Berger has released two important informational updates for its line-up of bullets. First, the Ballistics Coefficients (BCs) have been updated for the vast majority of bullets Berger sells. In addition, G7 model BCs are being provided for most of the bullets. You will want to use the updated BC data, which is based on actual testing of recent production lots of bullets.

Second, Berger is now providing a dual twist-rate recommendation for most bullets. Berger is now lists a “minimum” barrel twist rate as well as an “optimal” twist rate. To get maximum long-range performance from your bullets, use a barrel with the “optimal” rate of twist.

CLICK HERE for the latest Berger Quick Reference Sheets with updated BCs and new Optimal Twist Rates. Eric Stecker, Berger President says: “We have tested every lot of bullets‬ produced in the last several years to bring you these updated numbers for all of our bullets.”

Ballistic Coeffificent (BC) Updates with G7 Data
Berger notes: “We have updated all of our Ballistic Coefficients to be even more accurate.
Prior to 2008, all of Berger Bullets’ BCs were calculated using a computer prediction. Early in 2009, we began measuring BCs with live-fire testing. As a result, Berger’s BCs were updated and G7 BCs were also made available. This represented a dramatic improvement in the accuracy of performance data at that time. Since 2009, the BCs assessed for Berger Bullets have not been updated. As part of our ongoing effort to provide shooters with the best information possible, Berger has been testing every lot of bullets produced for the last several years. The result is updated and highly accurate running averages of BCs for recent production lots.

Here are some of the Updated BC Values for popular Berger Target (Match) Bullets:

Description New G1 BC New G7 BC % Change
22 Cal 80gr VLD Target 0.455 0.233 +2%
22 Cal 90gr VLD Target 0.534 0.274 -3%
6mm 95gr VLD Target 0.467 0.240 -3%
6mm 105gr VLD Target 0.517 0.265 +5%
6mm 105gr Hybrid Target 0.536 0.275 -1%
6mm 115gr VLD Target 0.563 0.289 +3%
6.5mm 130gr VLD Target 0.562 0.288 +2%
6.5mm 140gr Hybrid Target 0.607 0.311 -2%
7mm 180gr VLD Target 0.683 0.350 +4%
7mm 180gr Hybrid Target 0.680 0.349 +1%
30 Cal 155gr Hybrid Target 0.478 0.245 -1%
30 Cal 185gr Hybrid Target 0.576 0.295 +1%
30 Cal 215gr Hybrid Target 0.691 0.354 -1%

CLICK HERE for Complete Table with all bullets on Berger Website

G7 Form Factor Addition
Berger also added the G7 form factor to the Ballistics Quick Reference Sheet. The analysis of form factors can be very useful when considering a bullet’s long range performance potential. Going by BC alone can be deceptive since BC includes the weight and caliber of the bullet. Form factor indicates how much drag the bullet has, which is a very important consideration for all bullets of all calibers.

NEW Dual Twist-Rate Recommendations
Recommended twist rates for bullets are commonly listed as a single value, such as 1:12” (one rotation in 12″ of barrel travel). This may be overly simplistic. There is a big gray area of marginal stability in which bullets can fly with good accuracy, but with a reduced (i.e. sub-optimal) Ballistic Coefficient. Recognizing this reality, Berger is now listing two twist rates for each bullet it makes. The first is the minimum twist needed for good accuracy, which Berger has always recommended. The second is the new optimal twist rate, which is the twist that will stabilize the bullet to a level which achieves its full performance (BC) potential. CLICK HERE For more information.

Berger BC Ballistics Coefficient Barrel Twist Rate  Updates

Permalink Bullets, Brass, Ammo, Tech Tip 6 Comments »
October 19th, 2015

New Editions of Applied Ballistics Books

Applied Ballistics new book Long Range Shooting Bullet Data tables

Applied Ballistics LLC will release updated editions of two popular resource books: Applied Ballistics for Long-Range Shooting (3rd Edition) and Ballistic Performance of Rifle Bullets (2nd Edition). Retail price is $54.95 for each title, or $94.95 if purchased together. Pre-orders are now being accepted with a $5 discount per book. You can pre-order the new editions through the Applied Ballistics store. The new editions are expected to ship by the second week of December.

Applied Ballistics for Long Range Shooting (ABLRS), Bryan Litz’s “Magnum Opus”, will have significant enhancements. New for the Third Edition is content on Weapon Employment Zone (WEZ) analysis. WEZ analysis is the study of hit percentage, and how that will be affected by the uncertainties in your environment. Existing academic material is augmented with modern experimental findings. The Third Edition also includes a CD-ROM disc with Applied Ballistics’ latest version of its ballistic software. NOTE: The third edition of ABLRS does NOT include the library of bullet data. That bullet library now exists as a separate reference book: Ballistic Performance of Rifle Bullets.

Ballistic Performance of Rifle Bullets — Data for 533 Bullets AND Rimfire Ammo
The updated, Second Edition of Ballistic Performance of Rifle Bullets contains the current library of all modern bullets tested by the Applied Ballistics Laboratory. Expanding on the First Edition, which had data on 400 bullets from .22 to .408 caliber, this Second Edition contains data on 533 bullets from .22 through .50 caliber. In addition to the centerfire bullet data, the Second Edition contains live fire data on 90 types of rimfire ammo which were all tested for muzzle velocity and BC through five different barrels of various twist/length configurations. This library of experimental test data is the most extensive and accurate resource ever assembled for small arms bullets. Numerous modern ballistics programs draw from the library of tested BCs that are published in this book.

Permalink Bullets, Brass, Ammo, News 1 Comment »
September 12th, 2015

Coefficient Conundrum: G1 vs. G7, Which BC Should You Use

The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.

Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”

The simple answer to that is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.

G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.

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.]

Permalink Bullets, Brass, Ammo 3 Comments »
June 29th, 2015

Applied Ballistics Tests 50+ Types of .22 LR Rimfire Ammo

.22 LR Rimfire Ammunition testing Bryan Litz Applied Ballistics Eley
Photo shows Bryan Litz (on right) and tester Mitchell Fitzpatrick. Bryan said: “Only 2,445 rounds to go! We’re testing over 50 ammo types in five different twist barrels… science can be exhausting!”

Do you know the actual BC (Ballistic Coefficient) of your rimfire ammunition? Well Applied Ballisitics will soon have answers for you. Bryan Litz and his team of testers have been working on a Herculean project. They’ve been testing over fifty types of .22 LR ammo, using five different twist-rate barrels.

.22 LR Rimfire Ammunition testing Bryan Litz Applied Ballistics Eley

(more…)

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May 9th, 2015

Litz Field-Tests BCs of Sierra Tipped MatchKings

Following Sierra’s introduction of Tipped MatchKing (TMK) bullets, Bryan Litz of Applied Ballistics LLC has received many requests to determine the Ballistic Coefficient (BC) of these bullets through testing. Below are Litz’s findings for four out of the six bullets he has able to acquire and test so far.

Sierra Tipped MatchKing TMK Bullets Applied Ballistics G1 and G7 BC Coefficient

As you can see from the above table, when Sierra’s G1 BC is averaged for all speed ranges (which is representative of long range shooting) the results closely match the Applied Ballistics’ measurements of the same bullets, averaged from 3000 to 1500 FPS. The G7 BC doesn’t suffer nearly the velocity sensitivity as G1 and should be used for modern long range bullets when possible. Bryan tells us: “When I get the .22 caliber 77gr, and the .308 caliber 168gr tested, I’ll update the table.”

How do these Tipped MatchKings compare to standard MatchKings? According to Bryan’s measurements, here are some comparisons:

  • The 69gr TMK BC is +8% compared to the 69gr SMK
  • The 125gr TMK BC is -5% compared to the 125gr SMK (Litz believes this SMK was ‘pointed’)
  • The 155gr TMK BC is identical to that of the 155gr SMK (#2156, which is also pointed)
  • The 175gr TMK BC is +10% compared to the 175gr SMK

Bryan provided this additional advice for users of Ballistics programs: “Sierra’s stated BCs are measured by live fire, and are typically pretty accurate if the velocity bands are properly observed (7mm being the exception). A common error is to look at the BC that Sierra gives for your MV and just use that. Doing so overestimates the performance of the bullets over long range, and will cause you to hit low compared to your trajectory predictions.”

Permalink Bullets, Brass, Ammo 7 Comments »
December 21st, 2014

FREE Comprehensive Bullet Database — Bookmark It!

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 over 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 coverage of the Bullet Database is amazing. Manufacturers in the database include: A-Square, Barnaul, Barnes, Berger, Brenneke, Calhoon, CDP, CheyTac, ColoradoBonded, CT, DAG, David Tubb, Delsing, DEWC, DKT, DTK, DYN, Federal, Fiocchi, FMJ, FN, Fortek, FP, Freedom, Frontier, GECO, Gian-Marchet, GPA, GS-Custom, H&N, Hawk, HeviShot, Hirtenberger, Hornady, HP, Igman, IMI, IMI-Samson, Impala, JDJ, JLK, Klimovsk, Lapua, LEADEx, LEE, Lehigh, LIMA, LostRiver, LYM, MEN, Mil, Norinco, Norma, NorthFork, Nosler, PMC, PMP, Powell, PrviPartizan, Rainier, RCBS, Reichenberg, Remington, RN, RNFP, RUAG, RWS, Sako, Sellier-Bellot, Shilen, Sierra, Sinterfire, Speer, Stoklossa, SWC, Swift, Swiss, The Gun Haus, TMJ, WestCoast, Winchester, WM-Bullets and Woodleigh.

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.

ShooterForum Bullet Database

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December 18th, 2014

NEW Tipped MatchKing (TMK) Bullets from Sierra

Sierra has announced a new line of plastic-tipped MatchKing bullets. “Say What!? — that can’t be right…” you may be thinking. MatchKings have always been jacketed, hollowpoint bullets. Until now, plastic tips have been reserved for other Sierra projectiles, such as BlitzKing varmint bullets. But that is changing with the introduction of Sierra’s line of Tipped MatchKing (TMK) bullets featuring green acetal resin tips.

.308 30 caliber Sierra bullets tipped matchking TMK SMK

Plastic Tips Offer Better BC
Sierra says the plastic tips on TMKs enhance the Ballistic Coefficient (BC): “The major advantage of adding a tip to the bullet is the reduction of drag, producing a more favorable ballistic coefficient.” Stated BCs for the new TMK bullets are listed below. These BC numbers look good, and they have been verified with real-world testing: “We shot [all the new TMKs] multiple times (we actually test our BC numbers instead of letting a computer tell us what it is) and those numbers are all proven out!”

There will be six (6) new TMK bullets, two in .224 caliber, and four in .308 caliber. The six new tipped bullet types should be available in “early 2015″. Sorry, Sierra will not be offering 6mm, 6.5mm, or 7mm TMKs for the time being, although Sierra will introduce more TMK varieties in the future. Currently, Sierra is focusing on “the most popular calibers”. Notably, the new 22-Cal 77gr TMK has a 0.420 BC — identical to the BC of Sierra’s 80gr non-tipped HPBT MatchKing. So, you get the BC of a heavier bullet in a lighter projectile that can be pushed faster. That’s big news for .223 Rem and 22-250 shooters.

Bullet Name (Click for ballistic coefficients) Brand Item BC (G1)
.224 dia. 69 gr. Tipped MatchKing (TMK) .224 dia. 69 gr. Tipped MatchKing (TMK) Tipped MatchKing 7169 .375 @ 2700+ fps
.224 dia. 77 gr. Tipped MatchKing (TMK) .224 dia. 77 gr. Tipped MatchKing (TMK) Tipped MatchKing 7177 .420 @ 2400+ fps
.308 dia. 125 gr. Tipped MatchKing (TMK) .308 dia. 125 gr. Tipped MatchKing (TMK) Tipped MatchKing 7725 .343 @ 2580+ fps
.308 dia. 155 gr. Tipped MatchKing (TMK) .308 dia. 155 gr. Tipped MatchKing (TMK) Tipped MatchKing 7755 .519 @ 1900+ fps
.308 dia. 168 gr. Tipped MatchKing (TMK) .308 dia. 168 gr. Tipped MatchKing (TMK) Tipped MatchKing 7768 .535 @ 2050+ fps
.308 dia. 175 gr. Tipped MatchKing (TMK) .308 dia. 175 gr. Tipped MatchKing (TMK) Tipped MatchKing 7775 .545 @ 2400+ fps

New Bullet Shapes Along with Plastic Tips
In addition to the bullet tip, some of these new TMK bullets have slightly modified shapes compared to previous-generation, non-tipped MatchKings (SMKs) of like caliber/weight. Sierra’s technicians reported: “The [plastic] point on the tip is smaller than the meplat on a SMK and if you look, you will also see the ogive on most of these [new TMKs] have been changed as well. Most of the big BC gains are from the reshaped ogives from the legacy SMK product.”

TMK 7169 69 gr
TMK 7177 77 gr
TMK 7725 125 grTMK 7755  155 gr
TMK 7768 168 gr
TMK 7775 175 gr

.308 30 caliber Sierra bullets tipped matchking TMK SMK

Permalink Bullets, Brass, Ammo, New Product 19 Comments »
November 3rd, 2014

New Applied Ballistics Book Features Test Data for 400 Bullets

Applied Ballistics has just announced Ballistic Performance of Rifle Bullets. This new book is chock full of “mission critical” data on hundreds of popular projectiles. This latest reference book from Bryan Litz contains live fire test data on 400 modern rifle bullets. The data pages contained in this book are similar to the 225 bullet data pages found in Applied Ballistics for Long Range Shooting. The Ballistic Coefficient data is based on live fire testing methods which are repeatable within +/- 1%. If you’re looking for “rock-solid” info on the ballistic performance of today’s most popular rifle projectiles, this work is the definitive print resource. Scroll down to see a sample page from the new book.

Bryan Litz Bullet BookCLICK HERE to see the full list of bullets covered in this new resource book.

Visit the Applied Ballistics Online Store to pre-order your copy and save $5. Note: Pre-orders are expected to ship and arrive at USA destinations in time for Christmas. Retail price is $54.95, with a $5.00 pre-order discount.

More about the Book
“Modern rifles have reached an unprecedented level of accuracy. In many cases, the weak link in the chain of hitting targets is the trajectory modeling, which is based on bullet performance,” stated author Bryan Litz. Unfortunately, shooters can’t always rely on advertised Ballistic Coefficients (BCs) being accurate. Slight errors in BC modeling can be the cause of missing your target. Furthermore, a meaningful apples-to-apples comparison of bullet performance is not possible when the BCs are determined differently by various brands.

This book provides highly accurate ballistic performance data for 400 modern long range bullets from .224 to .408 caliber. By employing a common testing method for bullets of all brands, shooters are provided with consistent and accurate performance data which can be used to compare and select bullets, as well as to calculate accurate trajectories which put your shots on target at long range. It is claimed that the BC data is accurate (and repeatable) to +/- 1% for all bullets tested.

Detailed stability data is also included which can be used to determine suitable twist rates for bullets in various environments.

View Sample Page from Ballistic Performance of Rifle Bullets:
Bryan Litz Bullet Book Applied Ballistics BCs

NOTE: This is a reference book which contains mostly data pages. There is a single chapter in the beginning which talks about how to use the data. For a more thorough understanding of the science of external ballistics, readers are referred to: Applied Ballistics for Long Range Shooting (2d Edition).

Permalink Bullets, Brass, Ammo, New Product 11 Comments »
August 21st, 2014

Get Free Sierra Bullets Info Chart

How would you like to have the entire collection of Sierra rifle and pistol bullets at your fingertips, complete with bullet Ballistic Coefficients (BCs) and parts numbers? Well we’ve got you covered. Sierra publishes a handy PDF chart that displays all of Sierra’s popular projectiles, from .20 caliber all the way up to .50 caliber. CLICK HERE to download Sierra Bullets Chart.

CLICK Image to Download PDF Chart with All Sierra Bullet Types (2 MB file)
sierra bullets chart poster

Detail Sample from Chart
sierra bullets chart poster

Order Free Sierra Catalog
You can also get a free, hard copy poster with all Sierra’s bullet types. The current Sierra Bullets catalog has a printed insert that folds out into a large poster for your loading room or workshop. To order the current Sierra Catalog (with fold-out poster), visit Sierra’s Catalog Request Page.

Permalink Bullets, Brass, Ammo 1 Comment »
July 14th, 2014

Applied Ballistics Mobile App for Apple iOS Released

Applied Ballistics apple iphone ipad iOS appiPhone and iPad users rejoice. The Apple iOS version of the Applied Ballistics Mobile App is now available. It has all the features of the much-loved Applied Ballistics Android App with full Apple functionality. This mobile App will run on iPhones, iPods, and iPads.

Price is $29.99. Click here to view details or order the App: Applied Ballistics iOS App.

CLICK HERE for Detailed Summary of App Features (Applied Ballistics Website)

The new iOS mobile App accounts for all major and minor trajectory variables that a shooter could encounter. Conveniently, the App displays single-shot solutions in HUD View or Reticle View.

Real-World Calibration — Shooters can enter their observed drops and the program will calibrate and “true” the predictions based on actual bullet impact. This is done by incorporating muzzle velocity and drop-scaling over various segments of the trajectory.

Sync to Web — A web-sync feature allows you to store your rifle and ammunition libraries online. And you can backup all the profiles online or restore them to a device.

Forum member Snuggie308, who acquired the new iOS App, gives it a thumbs up: “I bought it last night. It is a great tool. There’s a massive data base … built into it. You can’t find a better [mobile ballistics app] in my opinion.” Snuggie308 also reports that the new iOS is iPad friendly, and fills the iPad screen so it is easy to use all the features.

Applied Ballistics apple iphone ipad iOS app Applied Ballistics apple iphone ipad iOS app

The Applied Ballistics iOS Mobile App runs the state-of-the-art Point Mass ballistic solver. This solver, along with the built-in library of ballistic coefficients, makes this the most accurate, precise, and complete mobile ballistics app available for iOS devices.

Ballistician (and former missile design engineer) Bryan Litz wrote this solver. The program integrates the equations of ballistic motion numerically, using a 4th-order Runge-Kutta method, the preferred method of solving dynamic equations for aircraft and missiles. The application also comes with G1 and G7 BCs for over 1,300 bullet types.

Bryan Litz tells us: “We have worked extensively on this product. With the success of the Android version of the application, released two years ago, the demand for the iOS version has been high. We are excited to now offer a full-featured iOS version that runs on iPhones, iPods, and iPads.”

Applied Ballistics apple iphone ipad iOS app Applied Ballistics apple iphone ipad iOS app

Available now through iTunes, the Applied Ballistics Mobile App costs $29.99, and requires iOS 7.0 or later for proper functionality. Compatible with iPhone, iPad, and iPod touch devices, this App is optimized for the iPhone 5 series of smart phones.

Permalink Bullets, Brass, Ammo, New Product 2 Comments »
June 26th, 2014

Modern Advancements in Long Range Shooting — By Bryan Litz

Litz Applied Ballistics Book Modern Advancements Long Range ShootingApplied Ballistics, LLC is offering an all-new book by Bryan Litz, the first in a series. The new 339-page, hard-cover book, Modern Advancements for Long Range Shooting, Volume I, documents the ongoing R & D being done at the Applied Ballistics laboratory, the “Area 51″ of the shooting world.

“This new series is heavily based in experimental ballistics, and takes a ‘Myth Busters’-type approach to many of the questions and problems faced by modern long range shooters,” stated Litz. Volume I of the series is scheduled for release in late July, 2014. The book will cost $39.95, but you can pre-order now for $35.95, a 10% savings.

Bryan adds: “Anyone interested in the underlying science behind shooting can benefit from this book. We address the important questions… How much does faster twist affect MV? How does stability affect BC from the muzzle and downrange? What chronographs are capable of high accuracy and precision? What characteristics should you look for in your long range rifle and optic set up? What new gadgets are being developed to enhance long range shooting?

New Book Features Extensive Live-Fire Test Results
Bryan tells us: “The book spotlights state-of-the-art technologies (and methodologies) in long range shooting. New equipment and old ideas are explored using experimental, live-fire testing. Extensive test results are reported in an easy-to-understand way. Among other things, our tests explore the effects of twist rate on muzzle velocity, BC (supersonic and transonic), precision, even spin rate decay for various rifling profiles as they are tested experimentally.

Chronographs and Optics Are Tested and Compared
Litz’s new book traces the evolution of modern rifle, bullet, and optic design. Results from chronograph comparison tests are presented, showing the strengths and weaknesses of available commercial chronographs. High-tech instrumentation such as laser rangefinders and wind measurement devices are explained in detail by contributing author Nick Vitalbo.

The New Book Puts Theory into Practice
We asked Bryan Litz how this new book differs from his previous treatises. Bryan replied: “My original Applied Ballistics for Long-Range Shooting book explains the fundamental elements of external ballistics. It’s the academic background which all future work relies on. The new book, Modern Advancements in Long Range Shooting, covers the ongoing development of equipment and ideas. We explore things like twist rate effects, modern rifle and optic design, and some of the high tech instruments which are being used to enhance the effectiveness of long range shooting.

Litz Applied Ballistics Book Modern Advancements Long Range Shooting

Permalink Bullets, Brass, Ammo, New Product 1 Comment »
January 6th, 2014

New Applied Ballistics Site Has Ballistics Calculator and More…

Applied Ballistics LLC has launched a completely updated website with many new features including an archive of FREE articles plus a full-featured online ballistics calculator. If you are interested in precision shooting, you should visit the “new and improved” Applied Ballistics website. Browse through the new content and try out the advanced Ballistics Calculator.

bullet data files

NEW Online Ballistics Calculator
There are many free online ballistics calculators, but the new Applied Ballistics web utility goes far beyond other web-based options. Bryan Litz states: “No ballistic solution can be more accurate than its inputs”. Accordingly, Applied Ballistics offers the most reliable BC data available — a built-in library of measured G1 and G7 BCs for over 200 bullets. The Online Ballistics Calculator also allows you to “offload” your results for use in the field in two ways. First, you can save a file for transfer to an Applied Ballistics Kestrel. (This process is supported with a ‘save profile’ option from the output page.) Alternatively, you can send the ballistics profile to Accuracy First DG to have a whiz wheel created.

bullet data files

The Online Ballistics Calculator has many “advanced” features. For example, you can enter sight scale factors to account for scopes which don’t track perfectly true, and also zero offsets which allows you to compensate for imperfect zeros. In addition, this is the first online ballistics program to provide dynamic WEZ (Weapon Employment Zone) analysis. This WEZ feature gives users the ability to calculate hit percentage on targets at a variety of ranges (and in various environments).

Bullet Data Files
The new website provides a number of detailed bullet data files. These data files include geometric dimensions, drag/BC data at multiple velocities, and detailed stability maps. The information is based on direct measurements and live fire testing conducted by Applied Ballistics.

bullet data files

Digital Media
The new Applied Ballistics website features a “digital library” of authoritative articles in PDF and eReader (Kindle, Nook) formats. You can download these FREE articles by clicking on the “Recreational” and “Professional” tabs at the top of Applied Ballistics Home Page, and then selecting “Recreational Articles” or “Professional Articles” from the pull-down menus.

Sample Ballistics Article
Gyroscopic (Spin) Drift and Coriolis Effect
Most long range shooters are aware of the effects of gravity, air resistance (drag), and wind vectors on their bullets’ trajectory. Gravity, drag, and wind are the major forces acting on a bullet in flight, but they’re not the only forces. In this article, Bryan Litz explains some of the more subtle forces that influence a bullet’s flight.

Sample Professional Article
300 Winchester Magnum vs. 338 Lapua Magnum WEZ Analysis
The specific intent of this Weapon Employment Zone (WEZ) report is to compare the ballistic performance of the 300 Winchester Magnum to the 338 Lapua Magnum with several available ammunition types. Understanding how these weapons compare in terms of hit percentage is important in the context of modern military applications.

Special Projects
Applied Ballistics is involved in some advanced, special projects. The new website showcases some of these high end ballistics solutions. Bryan Litz notes: “We have an active ballistics laboratory, highly capable contractors and industry partners who all contribute to provide practical and accurate solutions for a range of recreational and professional applications.”

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September 21st, 2013

Lapua Releases Doppler Radar Data for Lapua Scenar-L Bullets

Lapua has done extensive field testing of its bullets, using sophisticated Doppler radar equipment. Employing radar, Lapua has logged actual observed trajectories with a variety of bullet and cartridge types. And Lapua has just released updated radar data for Scenar-L bullets used with 6.5×47 Lapua, 6.5×55 Swede, and .308 Winchester chamberings. You’ll find this new data incorporated into Lapua’s product description tables for these three cartridge types.

Lapua doppler radar dataYou will also find both G1 and G7 BCs for the new line of Scenar-L Bullets in Lapua’s updated Components Table. Ballistic coefficients are based on Doppler radar data and calculated by Quick Target Unlimited Lapua Edition.

To find the BC for a particular bullet, go to the Components Table, select the caliber (on the left) and then look for the G1 or G7 value on the right for particular bullets. For example, the BCs for the new 136gr 6.5mm Scenar-L are 0.545 (G1) and 0.274 (G7).

If you are looking for the most precise trajectory predictions, nothing beats real-world testing like this. Bullet BCs can be calculated, “on paper”, from bullet size, weight, and shape. However, in the ‘real world’ the actual aerodynamic drag forces acting on the bullet change with velocity and other variables. Therefore, a bullet’s BC is NOT actually constant at every point in its flight path. Doppler radar allows Lapua to observe the actual drop of bullets at multiple points along their trajectory.

How much more precise are Doppler-radar-based trajectory predictions than typical drop charts based on modeled BCs? Consider this… when you plug the radar-based numbers for a .338 Lapua Magnum into Lapua’s ballistics software, the error in elevation is less than 2.5 cm (1″) at 1,500 meters. By contrast, the error based on a traditional G1 BC model could be over 1 meter (i.e. more than 40 inches).

Lapua doppler radar data

Free Lapua Ballistics Software for Android OS Devices
If you want to use Lapua’s Doppler Radar data for your own ballistics calculations — there’s a App for that. Lapua’s Quick Target Unlimited (QTU) software for Android OS can be downloaded for free from the Android Market. Predicted trajectories for this software are based on precise Doppler radar ballistic measurements of Lapua bullets, making this program much more accurate than other ballistic programs for mobile phones. Note, however, the Doppler Radar data is offered ONLY for Lapua-made bullets. This App does NOT include radar data for Berger, Sierra or other brands of bullets.

Lapua doppler radar data

Product tip from EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, News 3 Comments »
January 7th, 2013

G1 vs. G7 Ballistic Coefficients — What You Need to Know

The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.

Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”

The simple answer to that is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.

G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.

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.]

Permalink Bullets, Brass, Ammo, Reloading 16 Comments »