August 3rd, 2014

Big, Full-Color Wall Posters Show Cartridges at 100% Scale

Need something for the walls of your “man cave” or reloading room? Check out these jumbo-size cartridge posters. The creators of the Cartridge Comparison Guide now offer three very large full-color printed posters. These can be tacked to a wall or matted/framed to hang like paintings. Three different posters are available.

Rifleman’s Classic Poster (38″ x 27″)
The Rifleman’s Classic Poster, a full 38 inches wide and 27 inches tall, is the most comprehensive. This $19.95 poster displays 272 rifle cartridge types at true size (within 4/1000 of an inch). Cartridges shown range from .17 caliber all the way up to the big boomers (including some cannon shells). The Rifleman’s Classic poster includes all American Standardized Rifle Cartridges (as of 2013) and many European rifle cartridges. The poster is a good representation of military cartridges dating back to WWI and includes cartridges such as the 13X92mm MSR and the .55 Boys.

CLICK Image to Enlarge:
Big Bore Cartridge Comparison Guide Poster

American Standard Cartridge Poster (Rifle, Handgun, Shotgun) — $15.95
The 36″ x 24″ American Standard Poster displays 165 rifle cartridges, 55 handgun cartridges, and 9 different shotgun gauges. This includes all American Standardized Cartridges (rifle, handgun, and shotgun) available as of January 2012. All cartridge types are displayed in full color, actual size. The rifle selection includes all standard hunting cartridges from the 17 Mach 2 through the .505 Gibbs and .577 Nitro. Bonus cartridges include the .375 and .408 Chey-Tac, .416 Barrett, .50 BMG, 50-20 and 20mm. The Handgun section covers cartridges from the 17 HMR to the 500 S&W. Shotgun cartridges include the .410 and 32 gauge up to the 8 gauge. NOTE: Wildcat, proprietary, and obsolete-historic cartridges are NOT included in this poster.

CLICK Image to Enlarge:
Big Bore Cartridge Comparison Guide Poster

BIG BORE Cartridge Poster (215 Cartridges) — $15.95
The 36″ x 24″ Big Bore Poster illustrates over 215 large=caliber rifle cartridges, all shown actual size in full color. These include Standard, Historic, Military, Proprietary and Wildcat rifle cartridges side by side. Cartridges illustrated range from the subsonic .338 Spectre up to the monstrous .729 Jongmans. The poster also includes historically significant cartridges such as the 12 Gauge Paradox, 4 Bore, 1″ Nordfelt, 50 BAT Spotter, .50 BMG, .5 Vickers, 12.7×108 Russian, 20mm, 25mm, 30mm and more.

CLICK Image to Enlarge:
Big Bore Cartridge Comparison Guide Poster

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July 26th, 2014

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.]

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July 25th, 2014

How to Use Press-Mounted Bullet-Pulling Tools

In our Shooters’ Forum, a member recently noted that he needed to pull down (disassemble) some ammunition that was loaded incorrectly by one of his shooting buddies. You can use an impact puller to do this task, but if you have more than a dozen rounds or so, you may prefer to use a collet-style bullet puller. These work very quickly and positively, making quick work of big jobs. The efficiency of the collet-style puller is worth the investment if you frequently disassemble ammo. These devices retail for under $25.00 (collets sold separately). Normally, you’ll need a specific collet for each bullet diameter. But collets are not that costly, so this isn’t a big deal, particularly if you only load a few calibers, such as .223, 6mm, and .308.

Collet bullet-pullers resemble a loading die with a lever or handle on the top. They screw into a standard reloading press. Hornady and RCBS both make collet-style bullet pullers. They use the same basic principle — the device tightens a collet around the bullet, and then the bullet is separated from the case by lowering the press ram. NOTE: Collet pullers may leave small marks on your bullets, unlike impact (kinetic) pullers.*

Hornady collet bullet pullerHornady and RCBS use different mechanisms to tighten the collet around the bullet. On Hornady’s Cam-Lock Bullet Puller, a lever-arm on the top of the bullet puller serves to tighten the collet around the bullet. Simply rotate the lever from the vertical to the horizontal position to grab the bullet. Lower the ram to remove the case. The bullet will drop out when you return the lever arm to the vertical position. This is demonstrated in the video below:

Hornady Cam-Lock Bullet Puller Demonstrated

Hornady collet bullet pullerLike the Hornady tool, the RCBS Bullet Puller employs a collet to grab the bullet. However, the RCBS tool tightens the collet in a different way. The head of the RCBS tool is threaded internally. By rotating the lever arm clockwise in a horizontal circle you squeeze the collet around the bullet. To remove the bullet, after lowering the press ram, simply spin the lever arm back in the opposite direction. The use of the RCBS tool is demonstrated in this video:

RCBS Collet Bullet Puller Demonstrated:

WARNING: When removing bullets from loaded cartridges, always make sure there are no obsructions or debris in your shell-holder or under the loaded round. NEVER engage a primer seating accessory on your press when working with loaded rounds. You can cause a round to discharge by contacting the primer! Also, we recommend you keep your head and torso away from the bullet puller tool at all times.

*By contrast, impact pullers rarely mark bullets, particularly if you put a little bit of foam or paper wadding in the closed end of your impact puller. When dismantling loaded rounds, powder kernels can get trapped in the wadding, so you should remove and replace the wadding before changing to cartridges loaded with a different powder type (assuming you intend to save the powder).

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July 19th, 2014

Tips on Case-Trimming from PMA Tool

The folks at PMA Tool, makers of arbor presses, neck-turning tools, and other case-prep tools, offer some good advice about case trimming on the PMA Tool Blog. Here we reprint a PMA blog post that explains case trimming basics and helps you choose the right case-trimming tool for your needs.

Case Trimming Basics
Trimming the cartridge case to the proper length is a crucial step in case preparation that should not be overlooked or underestimated. The cartridge case or the rifle can be damaged, or even worse you get badly injured. In most instances cases should be trimmed after firing and sizing. Trimming new brass is necessary for a lot of wildcats and can be beneficial in some instances, but by and large, trimming new brass is not necessary for most situations (unless you are neck-turning). Cases should be trimmed after you have sized the case, because the expander ball on the decapping pin can (and will) stretch the neck. Those of us who neck size should get into the habit of trimming after sizing as well. This is a good rule of thumb to go by, and hopefully it will keep you safe during the reloading and shooting process.

There are so many case trimmers out there that work, deciding which one is right for you can be confusing. Even though I have trimmed thousands of cases, using about every method possible, I can’t answer the question of what case trimmer is right for you because of all the variables that may be involved. I can, however shed some light on the subject.

Wilson Micrometer Case Trimmer

The two most popular designs of trimmers either index (1) off the base or the head of the case, (2) off the shoulder or datum line of the case. There are pros and cons to each and it all depends on what you are willing to live with.

Indexing off the Base (Case Head)
Let’s talk about the first one I have listed, indexing off the base, or the head of the case. The pros to this method are that you can achieve a very accurate over all length and that is after all, what it is all about. The cons to this method are that you can get some variation doing it this way. Let me explain, the base is not always square to the body or can be damaged during firing especially if it is fired through a military style rifle with a very aggressive ejector. These cases should be discarded, but sometimes they can be overlooked. This condition can lead to an over all length that is incorrect. The case head being out of square will be corrected upon firing, however that case will wind up being shorter than the rest of your cases, possibly creating a difference in the neck tension on the bullet. The more you can do to eliminate variables in your reloads the better off you are going to be. This method can also be very slow, and if the user gets careless the result will be a inconsistent over all length.

Forster Case Trimmer

Indexing off the Shoulder (Datum Line)
The second method I mentioned, trimming off the shoulder or the datum line of the case, has its pros as well. I have found this to be the quickest of the methods and very accurate as well. After the case has been sized through the die the dimensions (particularly the headspace) of the cases are usually very uniform and exact, this allows the case to be trimmed by indexing off the shoulder. This method can be done very quickly, by hand, or by powering either the case, or the trimmer. You also don’t have to worry about the case heads being out of square with the body using this method. Generally the trimming time is cut in half, and this leads to greater focus on the job, without becoming careless. [Editor's Note: The World's Finest Trimmer (WFT) is one power device that indexes off the shoulder datum. It works fast and is very precise. The new WFT 2 Model with interchangeable trim chambers works with multiple cartridge types.]

Little Crow WFT

Summary
The choice is yours to make. I hope that this was some help to you, whether you are looking for your first trimmer or looking to replace the trimmer you have. Just remember to always put safety first and accuracy second, and you will start making little bug holes in no time.

Story Tip by EdLongrange. User Submissions are welcome.
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July 15th, 2014

Midsouth Waives Haz-Mat Fees on Primers (5 Box Minimum)

primers CCI Midsouth Shooters SupplyNeed Primers? Midsouth Shooters Supply (Midsouth) has a large selection of primers in stock right now. Yes Midsouth has the hard-to-find CCI BR-4 Small Rifle Benchrest primers, CCI 450s (small rifle magnum APS), Remington 6 1/2 small rifle, and Federal Large Rifle Magnum. Midsouth also has large quantities of Winchester primers. And if you need pistol or shotshell primers, Midsouth has plenty of those right now as well.

If you need an extra incentive to grab some primers, get this — for a limited time, Midsouth is offering FREE Haz-mat on Primer purchases. That’s right, Haz-Mat is FREE when you purchase five or more boxes of primers (mix and match qualifies). This offer is for ground shipping only, and regular shipping fees still apply. This offer ends July 20, 2014.

Hot Deal — FREE Haz-Mat with Purchase of Five or More Boxes of Primers.
primers CCI Midsouth Shooters Supply

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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.

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July 13th, 2014

Tempilaq and Green Label Thinner

Tempilaq is a temp-sensitive “paint-on” liquid coating which can be used to gauge case temperatures during the annealing process. Tempilaq is offered in 43 different temperature ratings from 175°F to 1900°F (79°C to 1038°C).

Tempilaq quickly dries, forming a dull, opaque film. Then, when heat is applied to that surface and the rated temperature is reached, the film liquefies, letting you know that you’ve reached the target annealing temp. Because you can ruin brass by over-annealing, we recommend using Tempilaq when annealing, at least when you are setting up your torch position and calculating the amount of time your cases should be exposed to the flame. To prevent premature “burn-off” you can apply the Tempilaq to the inside of the necks.

Thinner for Tempilaq
One of our Forum members from Australia was concerned about some 700° F Tempilaq he had recently obtained. He explained that it was thick and glue-like, making it hard to apply. He wondered if there was a thinner he could use with the 700° Tempilaq.

Yes there is such a product: Green Label Thinner from Tempil (the manufacturer of Tempilaq). Forum member Gary M. (aka gmorganal) tells us: “You can buy Temiplaq thinner from McMaster Carr, and they will have it on your doorstep about the time you hang up the phone. I just ordered from them this week, and [the thinner] was delivered the next day. The thinner is about half the price of the [Tempilaq] paints — roughly $5.00 or so per bottle.” Tempil explains: “Use Green Label Thinner to dilute Tempilaq G® or to replace evaporated solvent. For use only with Tempilaq G® temperature indicating liquid.”

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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

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June 22nd, 2014

Now That’s Accuracy — Mike Ezell’s Tack-Driving 30 Major

Sometimes everything comes together — a great barrel, the right load, good bullets, and, of course, a gifted trigger-puller. Check out this target from Forum member Mike Ezell. That’s five (5) shots at 100 yards from Mike’s 30 Major benchrest rifle. When this was shot a while back, Mike reported: “I fired a few groups in the great weather. No surprises — it did VERY well! My little wildcat, the 30 Major, has always been a shooter. That target was not a fluke — I shot a few groups today and Agg’d a high One.” Mike is a Kentucky gunsmith who builds his own rifles.

30 Major 6.5 Grendel 30 caliber PPC

30 Major is Based on 6.5 Grendel
What’s a “30 Major” you ask? This is Mike’s own wildcat, a 6.5 Grendel necked up to .30 caliber. Mike writes: “The 30 Major is essentially a .070″-long 30 PPC. With the great 6.5 Grendel brass available from Lapua, all you need to do is neck-up and turn the necks to prep the brass.” Mike says it is very much like a 30 BR, but you just start with 6.5 Grendel brass instead of 6mmBR brass.

The cartridge has one major benefit — it utilizes a PPC-diameter bolt face. That makes it easy to convert your group-shooting 6 PPC to shoot score with .30-cal bullets. Mike explains: “If you have a PPC, to shoot score, all you have to do is chamber up a [.30 caliber] barrel and screw it on your PPC.”

From 7.62×39 to 30 Major — Full Circle
Arms expert Neil Gibson has an interesting perspective on the lineage of the 30 Major. He reminds us that this wildcat has returned to its roots: “Start off with the 7.62×39 Russian [cartridge]. The Russians then modify it, necking it down to .223 for deer hunting. The U.S. bench rest guys then modify that, necking it up to 6 mm and blowing the case out making the 6mm PPC. Someone takes that case, necks it out to 6.5 mm, making the 6.5 PPC. Alexander Arms takes that and makes the 6.5 Grendel. Then finally Mike Ezell takes the Grendel and necks it up to 30 caliber, making the 30 Major. From 30 caliber, back to 30 caliber. OK, the original uses .31 caliber bullets, but the bore is still .300. Talk about almost coming round full circle!”

Great Accuracy Restored after Solving Mystery Problem
To get his 30 Major rig shooting this well, Mike had to solve a mysterious problem that cropped up last year. Mike explains: “Two years running, I have finished in the top 15 in IBS points shooting [the 30 Major], but last year’s benchrest season was tough.” Mike was having some accuracy issues that defied explanation. But he figured it out: “The front action screw was bottoming out against the barrel extension – just barely. A simple fix brought the gun back to life. It’s a Stiller Viper Drop Port. The action is screwed and glued into the stock, so I was a bit surprised … especially after having checked for [that issue] while looking for the problem. I’m just glad to have found the trouble so I can begin to re-instill some confidence in the gun and myself, after last year.”

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June 19th, 2014

Primers Available at Midsouth Shooters Supply

primers CCI Midsouth Shooters SupplyNeed Primers? Midsouth Shooters Supply (Midsouth) has a large selection of primers in stock right now. Yes Midsouth has the hard-to-find CCI BR-4 primers, as well CCI 450s (small rifle magnum), CCI 200s (large rifle), and CCI 250s (large rifle magnum). Midsouth also has large quantities of Rem 6.5s and Winchester rifle primers. If you need pistol or shotshell primers, Midsouth has plenty of those right now as well.

primers CCI Midsouth Shooters Supply

Get ‘Em While They’re Hot — These are In-Stock Today at 11:00 am ET
Here is a screenshot of some of the more popular rifle primers that were in-stock today (6/19/2014) at Midsouth. If you need ‘em, don’t hesitate to place your orders. You snooze, you loose.

primers CCI Midsouth Shooters Supply

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June 16th, 2014

How Barnes Bullets Are Made — Views from Inside the Factory

Barnes Bullets FactoryMany of our readers have been interested in learning how modern bullets are made. While a “boutique” bullet-maker, supplied with appropriate cores and jackets, can craft bullets using relatively simple hand dies and manual presses, factory production is different. The major bullet-makers, such as Barnes, employ huge, complex machines to craft their projectiles on an assembly line.

Modern hunting bullets are made with a variety of sophisticated (and expensive) machines, such as Computer Numerical Control (CNC) lathes, giant multi-stage presses, and hydraulic extruding machines that draw lead ingots into lead wire. Barnes offers an “inside look” at the bullet production process in a series of videos filmed at its Mona, UT factory. We’ve embedded four videos from the series here. These videos can also be viewed on the Barnes Bullets YouTube Channel.

Milling Slots in TSX All-Copper Bullet
This video shows how the slots (between the drive bands) in the TSX all-copper bullet are cut. The slots reduce the bearing surface that contacts the rifling. This helps reduce friction and heat, extending the life of barrels used with all-metal, drive-band bullets:

Varminator Bullets Produced in Jumbo Transfer Press
Here is the transfer press used in the production of Varminator and MPG Bullets. The process begins with a giant spool of flat copper material. The copper is stamped into jackets and eventually the formed Varminator bullets are ejected one by one into a bucket.

CNC Lathe Turns Bullets Automatically
In the video below, a Bar-Feed CNC crafts mono-bloc bullets from metal bar stock. Barnes uses a small CNC lathe to turn .50-caliber bullets from brass bar stock. We’re not sure which bullet is being made in this video. The material looks to be sintered metal. In the close-ups you can gold-colored shavings from when the machine was previously used for CNC-turned brass bullets.

Accuracy Testing in 100-yard Tunnel
Barnes regularly tests bullet samples for accuracy. In the video below, a Barnes technician loads sample rounds and tests them for accuracy in a 100-yard tunnel. The rounds are shot through a special fixture — basically a barreled action connected to parallel rods on either side. This allows the testing fixture to slide straight back on recoil (see it move back at 1:07-08 minute mark). Note how the tester actuates the trigger, which is oriented upwards, just the opposite of a normal rifle. The technician taps the upward-pointing trigger shoe lightly with a metal rod. Could this upside-down trigger orientation be useful in benchrest shooting — perhaps with railguns? It could make for an interesting experiment.

Story suggestion by EdLongrange. We welcome reader submissions.
Permalink - Videos, Bullets, Brass, Ammo 10 Comments »
June 13th, 2014

"How Do Bullets Fly?" — Great Online Resource

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

Bullet External Ballistics

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.

Bullet External Ballistics

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.

CLICK HERE to download “How Do Bullets Fly” complete text. (1.2 MB .zip file)

Photo and diagram © 2005-2009 Ruprecht Nennstiel, All Rights Reserved.

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