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February 5th, 2023

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

G1 G7 BC drag models

Over the past 12 months, this article was one of the TOP 20 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 preferable 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.]
This article is copyright 2023 AccurateShooter.com. No 3rd Party republication of this article is allowed without advance approval and payment of licensing fees.

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January 3rd, 2023

Test Your Ballistics Smarts with Shoot 101 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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November 21st, 2022

How Altitude and Barometric Pressure Affect Projectile Ballistics

altitude ballistics zeiss LRP S5 318-50 FFP scope
Photo shows the new ZEISS LRP S5 318-50 first focal plane (FFP) scope.

“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.”

Last month a good friend ventured to the high country of Colorado to pursue elk. He recently zeroed his rifle in California, at a range just a few hundred feet Above Mean Sea Level (AMSL). He wondered if the higher altitude in Colorado could alter his ballistics. The answer is a definite yes. However the good news is that free ballistics calculators can help you plot reliable drop charts for various shooting locations, high or low.

Suunto AltimeterThe question has been posed: “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, at higher altitudes, 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′ AMSL (Above Mean Sea Level) or less. I’ll need about 29-30 MOA to get from 100 yards to 1000 yards with a Berger 155gr VLD at 2960 fps. By contrast, in Raton, NM, located at 6600′ AMSL, 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.

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.

To learn more about all aspects of Exterior Ballistics, Hornady has a useful discussion of External Ballistics including the effects of altitude and temperature. To dig deeper, Sierra Bullets has a comprehensive Exterior Ballistics Resource Page with multiple sections from the Sierra Manual (4th and 5th Editions), including:

Section 3.0: Exterior Ballistic Effects on Bullet Flight
Section 3.1: Effects of Altitude and Atmospheric Conditions
Section 3.2: Effects of Wind
Section 3.3: Effects of Shooting Uphill or Downhill

Example from Section 3.0: “When a bullet flies through the air, two types of forces act on the bullet to determine its path (trajectory) through the air. The first is gravitational force; the other is aerodynamics. Several kinds of aerodynamic forces act on a bullet: drag, lift, side forces, Magnus force, spin damping force, pitch damping force, and Magnus cross force. The most important of these aerodynamic forces is drag. All the others are very small in comparison when the bullet is spin-stabilized.”

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October 19th, 2021

How Altitude Affects Bullet Ballistics (Drag and Drop)

altitude ballistics zeiss LRP S5 318-50 FFP scope
Photo shows the new ZEISS LRP S5 318-50 first focal plane (FFP) scope.

“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.”

It’s hunting season, and a good friend is heading to the high country of Colorado next week to pursue elk. He recently zeroed his rifle in California, at a range just a few hundred feet Above Mean Sea Level (AMSL). He wondered if the higher altitude in Colorado could alter his ballistics. The answer is a definite yes. However the good news is that free ballistics calculators can help you plot reliable drop charts for various shooting locations, high or low.

Suunto AltimeterThe question has been posed: “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, at higher altitudes, 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′ AMSL (Above Mean Sea Level) or less. I’ll need about 29-30 MOA to get from 100 yards to 1000 yards with a Berger 155gr VLD at 2960 fps. By contrast, in Raton, NM, located at 6600′ AMSL, 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.

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.

To learn more about all aspects of Exterior Ballistics, Hornady has a useful discussion of External Ballistics including the effects of altitude and temperature. To dig deeper, Sierra Bullets has a comprehensive Exterior Ballistics Resource Page with multiple sections from the Sierra Manual (4th and 5th Editions), including:

Section 3.0: Exterior Ballistic Effects on Bullet Flight
Section 3.1: Effects of Altitude and Atmospheric Conditions
Section 3.2: Effects of Wind
Section 3.3: Effects of Shooting Uphill or Downhill

Example from Section 3.0: “When a bullet flies through the air, two types of forces act on the bullet to determine its path (trajectory) through the air. The first is gravitational force; the other is aerodynamics. Several kinds of aerodynamic forces act on a bullet: drag, lift, side forces, Magnus force, spin damping force, pitch damping force, and Magnus cross force. The most important of these aerodynamic forces is drag. All the others are very small in comparison when the bullet is spin-stabilized.”

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April 18th, 2021

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 Outdoor, parent of 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. There were a variety of interactive offerings that let you test your knowledge.

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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November 21st, 2020

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 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, and Wound Channel Characteristics.

New Content in Second Edition of Cartridge Comparison Guide
The Cartridge Comparison Guide (Second Edition) costs $29.99 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….”

Black Rifle Cartridge Comparison Guide

The Black Rifle Cartridge Comparison Guide (CCG) was created for semi-auto AR-platform and Modern Sporting Rifle users. The Black Rifle CCG covers virtually all popular rifle, shotgun, and handgun cartridge types used with magazine-fed, semi-automatic black rifles or AR “pistols”. There is information for 50 unique rifle cartridges plus shotgun and handgun cartridges. The book provides ballistics data for all these cartridges via easy-to-use data tables. The tables cover factory ammunition and handloaded cartridges, included the newer .224 Valkyrie.

black rifle cartridge guide book

The data tables compare standardized rifle and handgun cartridges from .17 caliber to up to .50 caliber. The book also provides data for 20-, 16-, and 12-gauge Shotgun cartridges. A handy summary table identifies each rifle cartridge presented and notes if it can be fired from a factory available MSR platform, a semi-custom platform/upper, as well as a semi-custom barrel. This 275-page, spiral-bound book is on sale now for $21.99.

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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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 »
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.

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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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