If you haven’t visited the Norma website recently, you should click over to www.norma.cc/en/ (the ‘en’ is for English version). There you will find Norma’s “Ammo Academy”, a technical resource that provides information on: Ballistics, Powder Storage, Barrel Wear, and Bullet Expansion. In addition, the Ammo Academy now links to Norma’s Reloading Data Center, where you’ll find loads for nearly 70 cartridge types including: .223 Rem, .22-250, 6mmBR Norma, 6XC, 260 Rem, 6.5-284, 6.5×55, 7mm-08, .270 Win, .284 Win, .308 Win, .30-06, 300 Win Mag, .338 Lapua Mag and dozens more.
The Ammo Academy’s Ballistics section contains some fascinating technical facts:
After the trigger is pulled, it takes around 0.005 seconds before the firing pin reaches the primer.
From the firing of the primer it takes 0.0015-0.002 seconds until the bullet exits the muzzle.
When the bullet leaves the muzzle, the hot gases surround and overtake the bullet, continuing the acceleration for a few centimeters.
Because the barrel is always angled slightly upwards, the bullet’s flight starts about 3-5 cm below the line of sight.
Norma also offers some good advice about Powder and Cartridge Storage:
To maintain the product quality for as long as possible, you have to keep the powder in a suitable place under suitable conditions. Where possible, store the powder at a constant temperature, ideally between 12 and 15°C (54°F to 59°F), and a relative humidity of 40–50%. If the air is too dry, it will dry out the powder, which will cause the pressure to be higher, thus affecting performance. Also make sure that you close the powder container properly afterwards. Cartridges should be stored under the same ambient conditions to maintain their quality.
In this NSSF Video, Ryan Cleckner, a former Sniper Instructor for the 1st Ranger Battalion, explains how to gather and organize D.O.P.E. (Data On Previous Engagements) and how to organize this information to make it readily available in the field. As the term is used by Cleckner, D.O.P.E. includes observed bullet drop information at various distances, as well as the effects of wind, temperature changes, humidity and other environmental variables.
If you know your muzzle velocity, and bullet BC, a modern Ballistics App should be able to calculate bullet drop with great precision at distances from 100-1000 yards — often within a couple 1/4-MOA clicks. However, because a bullet’s BC is actually dynamic (changing with speed), and because ballistics solvers can’t perfectly account for all variables, it’s useful to collect actual, verified bullet drop data.
It’s smart to start with ballistics data from a solver app, but, as Cleckner explains: “Odds are, you’re going to have to fine-tune that data to your gun and your system. Every scope and every rifle and every bullet [type] act differently. Your scope may not track the same from rifle to rifle, so it’s important you get the data that’s unique to you.” Cleckner also explains that the ballistic data supplied with some factory ammo may only give you a crude approximation of how that ammo will actually shoot through your gun.
Keeping Your Drop Data with the Rifle
Cleckner also offers some good advice on how to record D.O.P.E. on simple index cards, and how to keep your ballistics data with your rifle. This can be done with a laminated drop chart or data transferred to a scope cover (photo right). CLICK HERE, to learn more about creating handy field data cards.
At the 4:15 mark on the video, Cleckner shows a calibrated tape he has fitted around the turret of his riflescope. The tape shows distance numbers (e.g. “4″ for 400 yards, “5″ for 500 yards etc.) that correspond with the number of clicks (rotation) required to be zeroed at that particular distance. With that system, you simply “dial your distance” and your point of impact should equal your point of aim. It takes some skill (and the right software) to create these tapes, but the concept is great.
At the end of this year, Berger Bullets plans to introduce a new projectile that may truly be the most revolutionary bullet design since the advent of jacketed spitzers in the late 19th Century. Berger’s new bullet is unlike anything we have ever seen before. It features concentric curved ridges, or “ripples”, on the bearing surface. Tests show that this new projectile, dubbed the “Sonic Ripple Bullet”, has signficantly less drag than conventional bullets (no matter what their ogive configuration). In addition, the Sonic Ripple design provides increased stability at all velocities (allowing barrels with slower twist rates for a given bullet weight).
So, what does all this mean in practical terms? Well, compared to conventional bullets (of similar weight/size), the Sonic Ripple Bullet will shoot a flatter trajectory, buck the wind better, retain energy longer, and remain stable for a much longer distance. That’s big news for competitive shooters, tactical shooters, and long-range hunters.
The Science of the Sonic Ripple Bullet Design
Bryan Litz, Ballistician for Berger Bullets, explains: “This radical leap forward in bullet design was made possible by advanced, new bullet-making technologies. The unusual bullet appearance is only part of the revolutionary ‘Sonic Ripple’ system. The curvilinear waves or ripples in the bullet jacket are designed to create a specific resonance when fired from a specially ‘tuned’ barrel system. The result is an optimization of the sonic wavefront created by the bullet as it travels through its trajectory. This wavefront optimization simultaneously reduces bullet drag while increasing bullet stability.”
In essence, the supersonic shock-wave is smoothed out, dramatically reducing secondary wave fronts. This is all good, as Bryan explains: “If all the internal ballistic requirements are met, the Sonic Ripple bullet exits the muzzle with a harmonically-stabilized launch dynamic. As a further benefit of the ripple design, tests show that the concentric ripples also enhance boundary layer airflow attachment on the bullet. This, in turn, dramatically reduces wake turbulence and attendant drag.”
The reduction of wake turbulence (combined with wavefront optimization) represents a “major breakthrough” which should increase projectile BC by at least 0.14 (on G7 scale), according to Bryan. But, we wondered, might the increased surface area associated with the ripples slow the bullet down in flight? Actually, no. Bryan explained: “Eddies in the boundary layer around the ripples actually lower skin friction drag which more than compensates for increased surface area, resulting in a net friction drag loss at all velocities — both supersonic and transonic.”
Sonic Ripple Bullets Available by the End of 2013
When will we see Sonic Ripple Bullets on dealers’ shelves? Maybe this year. Berger’s marketing department told us: “The Sonic Ripple technology is currently under development and is expected to mature enough for commercial application by late fall, 2013.”
Here’s a Ballistics Trivia challenge, put together by Bryan Litz of Applied Ballistics LLC. Bryan is Berger Bullets’ Ballistician and the author of Applied Ballistics for Long Range Shooting. Bryan posed the following Ballistics Question about Kinetic Energy and Aerodynamic Drag:
Consider a .30 caliber 175 grain bullet with a G7 BC of .259 (Berger 175 OTM) fired level at a muzzle velocity of 2650 fps in standard (ICAO) sea level conditions.
As this bullet flies downrange, it loses velocity due to aerodynamic drag. As the velocity of the bullet decays, so does its Kinetic Energy (in ft-lbs). The Kinetic Energy lost by the bullet in a given amount of time can be defined in terms of power.
Another way to think about this is that the aerodynamic drag on the bullet can be expressed in terms of power, calculated from the projectile’s change in Kinetic Energy over flight time.
Question: How much power (expressed in Watts) is applied to the bullet by aerodynamic drag on average over:
A) 500 yards?
B) 1000 yards?
C) 1500 yards?
Guesses are welcome, but this one can be calculated exactly.
On LongRangeHunting.com, you’ll find a good article by Shawn Carlock about wind reading. Shawn is a veteran law enforcement marksman and a past USPSA national precision rifle champion. Shawn offers good advice on how to estimate wind speeds and directions using a multitude of available indicators — not just your wind gauge: “Use anything at your disposal to accurately estimate the wind’s velocity. I keep and use a Kestrel for reading conditions….The Kestrel is very accurate but will only tell you what the conditions are where you are standing. I practice by looking at grass, brush, trees, dust, wind flags, mirage, rain, fog and anything else that will give me info on velocity and then estimate the speed.”
Shawn also explains how terrain features can cause vertical wind effects. A hunter on a hilltop must account for bullet rise if there is a headwind blowing up the slope. Many shooters consider wind in only one plane — the horizontal. In fact wind has vertical components, both up and down. If you have piloted a small aircraft you know how important vertical wind vectors can be. Match shooters will also experience vertical rise when there is a strong tailwind blowing over an up-sloping berm ahead of the target emplacements. Overall, Shawn concludes: “The more time you spend studying the wind and its effect over varying terrain the more successful you will be as a long-range shooter and hunter.”
One 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 Kestral, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.”
You can do your own experimental calculations using JBM Online Ballistics, or the FREE Point Blank Ballistics software. 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.
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.
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.
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.]
New 3000 FPS Rimfire Round Winchester has announced a new, high-velocity 17-caliber rimfire cartridge, the .17 Winchester Super Magnum (aka .17 Win Super Mag). The .17 Win Super Mag will initially be offered in three bullet types: 20gr plastic tip (Varmint HV), 25gr plastic tip (Varmint HE), and a 20gr JHP (Super-X). The 20-grain varieties boast a 3000 FPS muzzle velocity, earning honors as the fastest Rimfire ammo ever made.
.17 Winchester Super Mag Specifications
Symbol
Sub Brand
Bullet Weight
Muzzle Velocity
S17W20
Varmint HV
20-gr Plastic Tip
3,000 fps
S17W25
Varmint HE
25-gr Plastic Tip
2,600 fps
X17W20
Super-X
20-gr JHP
3,000 fps
Winchester claims that all .17 Win Super Mag ammo types shoot much flatter than the .22 Win Mag and .17 HMR, while delivering more than 150 percent more energy than both. In addition, the .17 Win Super Mag “bucks the wind” better than any other rimfire ammo — exhibiting significant less horizontal drift at extended ranges. The ammunition should be available at Winchester dealers by April 2013.
Savage Will Release a .17 Win Super Mag Rifle
According to Outdoor Life’s John Snow, Savage will be the first gun-maker to produce rifles chambered in .17 Win Super Mag. Snow says Savage “hopes to have rifles shipping by mid-April”. Winchester states that, later in 2013, two other manufacturers will introduce .17 Win Super Mag rifles.
Ron Spooner writes: “For perspective, contrast the 17 Win Super Mag (no relation to the WSM centerfire cartridges) against the former rimfire velocity champ, the popular .17 Hornady Magnum Rimfire. While the 17 HMR shoots delightfully flat, the 17 Win Super Mag shoots two times flatter and drifts only half as far in the wind. Its 20-grain bullets retain more than twice as much downrange energy, and its 25-grain projectiles nearly triple the energy of the 17-grain V-Max in the HMR load”. Read Ron Spooner Review.
Watch Video Trailer for .17 Win Super Mag Rimfire Ammo
The .17 Win Super Mag offers higher velocities and more downrange energy than ever before. “Our engineers have been developing the top-secret .17 Win Super Mag [cartridge] for more than three years,” said Brett Flaugher, Winchester Ammunition vice president of sales, marketing and strategy. “At 3,000 feet per second it’s the fastest modern rimfire cartridge on the planet. The downrange energy deposited by the .17 Win Super Mag will be a game-changer for varmint and predator hunters everywhere. Now hunters will get the downrange performance of a centerfire cartridge at the more affordable price point of traditional rimfire ammunition. It’s the best of both worlds[.]”
Spawn of a .27-Caliber Nail-Gun
Believe it or not, Winchester’s new .17 Win Super Mag evolved from a “parent case” originally developed for .27-caliber powder-actuated concrete nail guns. Winchester has produced millions of nail gun blanks in .22, .25, and .27 calibers. This new .17 Win Super Mag is derived from Winchester’s .27-cal nail gun blank, necked down to .17-caliber and strengthened with a thicker head and stronger case-walls. With case-walls that are 50% thicker than those on 17 HMR cartridges, the .17 Win Super Mag can operate at 33,000 psi. By contrast, the 17 HMR maxes out at 26,000 psi.
Comment: Will the .17 Win Super Mag Rimfire Round Be a Hit or a Miss?
Initial tests of the .17 Win Super Mag show good ballistic performance compared to the 17 HMR. On the other hand, early accuracy reports have been mediocre, but keep in mind that the gun magazine tests were performed with prototype rifles, on make-shift, wobbly rests (that’s typical). It will be interesting to see how the round can really perform in a good barrel when shot from a stable rest by a skilled trigger-puller.
Economics may dictate whether the .17 Win Super Mag catches on. We’re told this new cartridge will sell for $17.99 per 50-round box. That works out to $0.36 per round, making it about 40-50% more costly than the popular 17 HMR which now sells for $11.50 to $14.00 per 50-round box. At $0.36 per round, the .17 Win Super Mag may exceed the cost of 17-cal centerfire reloads, but then you have the convenience of pre-made ammo. We think that, if the cartridge proves accurate, varmint hunters will pay the extra money (over the 17 HMR) for the added performance, which is pretty significant at 150 yards and beyond. For a squirrel shooter or prairie dog hunter, the .17 Win Super Mag is still much less expensive than the cheapest US-made .223 Rem ammo, which sold for about $10 – $12 per 20-round box (i.e. $0.50 – $0.60 per round) before the current buying frenzy.
Story tip by EdLongRange. We welcome reader submissions.
Thomas Haugland, a Shooters’ Forum member from Norway, is a long-range target shooter and hunter. He has created an interesting video showing how to gauge wind velocities by watching trees, grass, and other natural vegetation. The video commentary is in English, but the units of wind speed (and distance) are metric. Haugland explains: “This is not a full tutorial, but rather a short heads-up to make you draw the lines between the dots yourself”. Here are some conversions that will help when watching the video:
.5 m/s = 1.1 mph | 1 m/s = 2.2 mph | 2 m/s = 4.5 mph
3 m/s = 6.7 mph | 4 m/s = 8.9 mph | 5 m/s =11.2 mph
Christmas Day is just one week away. Books have always been popular Xmas gifts. If you haven’t completed your holiday shopping, here are some recommended titles that should please the serious shooters and firearms enthusiasts on your shopping list. For Shooting Clubs, books also make great end-of-season member awards. Most of us would rather have a useful book than one more piece of wood to toss in a box in the closet.
Here are six recommended titles, in alphabetical order:
If you’re a serious long-range shooter you NEED this book. Since its initial release Bryan Litz’s treatise has become the definitive resource on long-range ballistics and bullet design. While Bryan covers some very advanced topics, Bryan does a very good job of making the text comprehensible to the layman. You don’t need a degree from MIT to read this work. Bryan’s book comes compete with a CD packed with ballistics software and additional reference materials. AND, Bryan includes Ballistic Coefficient data for over 236 long range bullets.
Frederick Selous was a legendary African hunter. It was for him that Tanzania’s famous Selous Game reserve was named. If you have an interest in big game hunting in Africa, you should get this book. As readers have noted, this is “Classic Africana”… “one of the very best exploration/hunting history books about Africa”. It is an excellent book, well-written and “all about hunting”. Selous’ life was full of adventure, and his book lets readers experience, vicariously, the danger and excitement of African hunting in a bygone era.
This handy reference guide contains scores of useful tips from many top shooters. However, this is NOT a load manual. Rather, it explains the techniques for precision reloading, and offers advice on how to get the “Nth” degree of accuracy from your handloads. Each topical chapter is authored by a different expert. Chapters include: Reloading for Extreme Accuracy, High Power (Bolt Guns), High Power (Gas Guns), Benchrest, Magnums, Wildcats, Cast Bullets, and working up an accuracy load. Readers have praised this compact (5.5″ x 8.5″) reference: “I’ve been reloading for many many years, and [this] book still managed to contain pearls of wisdom I’d never heard before.” –T. Pratt.
Tompkins’ treatise is a must-read for serious Palma,
F-Class, and High Power shooters. The revised and updated edition is set for release in 2013. Topics include Mental & Physical training, Reading Wind & Mirage Shooting Fundamentals, International Competition, and Loading for Long Range. Nancy Tompkins is a 4-time winner of the National Long Range Championships, and has won countless other major events. Nancy has been on six Palma Teams (as both a shooter and a coach).
Decades after it was written, Vaughn’s work remains a seminal treatise on accuracy. Vaughn was a serious scientist, working for the Sandia National Laboratories. Many “gun writers” toss out hunches about rifle accuracy. Vaughn, by contrast, did serious empirical testing and statistical analysis. Vaughn wondered why some guns shot well while seemingly identical rifles did not. Rifle Accuracy Facts covers a wide variety of topics, including internal ballistics, chamber design, barrel vibration, bullet imbalance, external ballistics, scope design and more. Writer Boyd Allen notes: “If you are serious about precision shooting, Vaughn’s book belongs in your library.”
Steven Boelter’s 352-page book is a comprehensive study of all types of rimfire ammunition (including 17s and 22 mags), with over 600 photos. In a remarkable undertaking, Steven Boelter fired every brand and sample of rimfire ammo he could acquire (including 22LR, 17 Mach 2, 17HMR and 22 WMR), and recorded all the results. In all, Steven tested 11 brands and 137 different rimfire rounds, firing over 32,000 test rounds.
Bryan Litz, Ballistican for Berger Bullets, is actually a trained rocket scientist, not to mention a skilled long-range shooter. Bryan’s books on Ballistics and Precision Long Range Shooting have been recognized as the leading resources of their kind in print. Now you can save money on Bryan’s highly-regarded books through a special holiday promotion.
Bryan tells us: “For a limited time, we are taking an additional $5 off the retail price of our titles Applied Ballistics for Long Range Shooting 2nd Ed. (regularly $49.95, $44.95 on sale) and Accuracy and Precision for Long Range Shooting (regularly $34.95, $29.95 on sale). And, by purchasing direct from Applied Ballistics you can get your copy autographed by the author”.
Here are what others are saying about these books.
“Got my copy of Accuracy and Precision for Long Range Shooting and can’t put it down! Exceptionally well done! Both this and Applied Ballistics for Long-Range Shooting” are definite requirements for all long range shooters!” — Eric K.
“Thanks, Brian. You have opened up a whole new ‘world’ in shooting, for those of us who love shooting and hunting, but don’t have the academic background to really appreciate the intricacies of science.” — Terje N.
Ruprecht Nennstiel, a forensic ballistics expert from Wiesbaden, Germany, has authored a great resource about bullet behavior in flight. Nennstiel’s comprehensive article, How Do Bullets Fly, explains all the forces which affect bullet flight including gravity, wind, gyroscopic effects, aerodynamic drag, and lift. Nennstiel even explains the rather arcane Magnus Force and Coriolis Effect which come into play at long ranges. Nennstiel’s remarkable resource contains many useful illustrations plus new experimental observations of bullets fired from small arms, both at short and at long ranges.
Shadowgraph of .308 Winchester Bullet
A convenient index is provided so you can study each particular force in sequence. Writing with clear, precise prose, Nennstiel explains each key factor that affects external ballistics. For starters, we all know that bullets spin when launched from a rifled barrel. But Nennstiel explains in greater detail how this spinning creates gyroscopic stability:
“The overturning moment MW tends to rotate the bullet about an axis, which goes through the CG (center of gravity) and which is perpendicular to the plane of drag, the plane, formed by the velocity vector ‘v’ and the longitudinal axis of the bullet. In the absence of spin, the yaw angle ‘δ’ would grow and the bullet would tumble.
If the bullet has sufficient spin, saying if it rotates fast enough about its axis of form, the gyroscopic effect takes place: the bullet’s longitudinal axis moves into the direction of the overturning moment, perpendicular to the plane of drag. This axis shift however alters the plane of drag, which then rotates about the velocity vector. This movement is called precession or slow mode oscillation.”
Raise Your Ballistic IQ
Though comprehensible to the average reader with some grounding in basic physics, Nennstiel’s work is really the equivalent of a Ph.D thesis in external ballistics. You could easily spend hours reading (and re-reading) all the primary material as well as the detailed FAQ section. But we think it’s worth plowing into How Do Bullets Fly from start to finish. We suggest you bookmark the page for future reference. You can also download the complete article for future reference and offline reading.
Keeping Your Drop Data with the Rifle
The Science of the Sonic Ripple Bullet Design
Consider a .30 caliber 175 grain bullet with a G7 BC of .259 (Berger 175 OTM) fired level at a muzzle velocity of 2650 fps in standard (ICAO) sea level conditions. 
One 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.
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.
Drag Models — G7 is better than G1 for Long-Range Bullets
New 3000 FPS Rimfire Round
Spawn of a .27-Caliber Nail-Gun
Christmas Day is just one week away. Books have always been popular Xmas gifts. If you haven’t completed your holiday shopping, here are some recommended titles that should please the serious shooters and firearms enthusiasts on your shopping list. For Shooting Clubs, books also make great end-of-season member awards. Most of us would rather have a useful book than one more piece of wood to toss in a box in the closet.
