Category Archives: Ammunition

The 5.56 Timeline is Dead! Long live the 5.56 Timeline!

Use the links on the left of the page to navigate through the many html pages of the Timeline, organized by year.

One of the key resources for anyone interested in the long process of development of the small-caliber, high-velocity concept, leading up to the American adoption of the 5.56mm M16 and M16A1 rifles in 1963, and ultimately to every major army’s basic issue rifle today, has been Daniel E. Watters’s “5.56 Timeline,” developed over a lifetime of research and published until recently on Dean Speir’s site, The Gun Zone.

Five years ago, mentioning a resurce Daniel had turned us on to, we wrote, “For an overview of M16 development with lots of good links, you can’t really beat his page at The Gun Zone,” (adding a link that is now pining for the fjords).  A year later, we mentioned it again.

By 2015, we were calling Daniel’s 5.56 Timeline “indispensable” and it truly was, so it was pretty shocking when The Gun Zone closed down, and it went off the net… for a while.

Daniel explains it as follows:

This article was originally published at The Gun Zone — The Gunperson’s Authoritative Internet Information Resource. My friend and mentor Dean Speir has graciously hosted my articles at TGZ for nearly 16 years. These articles would likely have never appeared online without his constant encouragement and assistance.

With TGZ’s closure in early 2017, Dean encouraged me to find a new home for my scholarship so it wouldn’t be lost in the dustbin of the Internet. Loose Rounds has welcomed me with open arms. In the future, I intend to expand my legacy TGZ articles and add new contributions here at Loose Rounds.

While we regret the demise of TGZ, we’re thankful that this priceless Timeline was saved.

It’s now a permanent Page at Loose Rounds.

One thing that would make this Timeline really come alive is adapting it to an actual graphical timeline. Just thinking out loud, the 5.56 Timeline would make a great application for Scott ‘s internet startup, WhenHub.

Powder Pioneer: Antoine-Laurent Lavoisier

Antoine Lavoisier was a reformed lawyer, whose curiosity made him, in some ways, the modern founder of the science of chemistry; and whose patriotism and scientific acumen led him to the leadership of King Louis’ XVI’s powder works in the very peak days of the Bourbon monarchy in France.

In other words, his timing could have been better.

The son of well-to-do, educated parents, he took the law degree as his father wished, but appointment to the privatized firm that collected Louis’s taxes gave him an income of his own and the freedom to pursue chemistry. He is revered today as one of the founding fathers of the science; his book, Traité élémentaire de chimie, was published in 1789 and was the first textbook of the science of chemistry — arguably the first textbook of science, period.

In 1775, the King appointed him as one of France’s Gunpowder Commissioners. Chem Heritage:

In 1775 Lavoisier was appointed a commissioner of the Royal Gunpowder and Saltpeter Administration and took up residence in the Paris Arsenal. There he equipped a fine laboratory, which attracted young chemists from all over Europe to learn about the “Chemical Revolution” then in progress. He meanwhile succeeded in producing more and better gunpowder by increasing the supply and ensuring the purity of the constituents—saltpeter (potassium nitrate), sulfur, and charcoal—as well as by improving the methods of granulating the powder.

Thus, chemistry was bound up with armaments even in its creation. As Michael Freemantle puts it in Gas, Gas, Quick, Boys!:

Gunpowder provides another example of the application of chemistry to warfare. The powder consists of a mixture of charcoal, the chemical element sulfur and one chemical compound – potassium nitrate. Its use in warfare dates back to the introduction of the gun as a weapon in the fourteenth and fifteenth centuries. In fact, gunpowder chemistry also played a role in the birth of modern chemistry as we now know it.

His contributions to chemistry include such fundamentals as the naming of oxygen and hydrogen, and the understanding of how they could be combined to synthesize water, or water split to produce them. And someone had to be the first one to understand and report that the mass of reaction ingredients must equal the mass of reaction products — that someone was Lavoisier.

M Lavoisier and his wife, by French master Henry-Louis David. The scientific apparatus in the portrait is described here.

Putting a state arsenal on a scientific basis using these principles gave France a technological advantage in its longstanding conflicts with its neighbors, especially its cross-Channel nemesis. As mentioned above, improving the purity of the ingredients in the mixture, and adjusting the granulation of the powder, went a long way to improve the power, consistency, and reliability of gunpowder in the later 18th Century. This superior powder, made in the royal arsenals, using Lavoisier’s scientifically improved methods, was shipped in quantity from France to their allies in the endless wars with England, the American revolutionaries.

Unfortunately for Lavoisier, revolution didn’t stay on the far side of the Atlantic. Being in the good graces of the King had just hit its sell-by date, and hit it hard.

The American Chemical Society, as part of an in-depth exploration of the man and his impact, closed with this description of the end of Lavoisier:

Ironically, Lavoisier, the ardent and zealous chemical revolutionary, was caught in the web of intrigue of a political revolution. The TraitÉ was published in 1789, the same year as the storming of the Bastille. A year later, Lavoisier complained that “the state of public affairs in France…has temporarily retarded the progress of science and distracted scientists from the work that is most precious to them.”

Lavoisier, however, could not escape the wrath of Jean-Paul Marat, the adamant revolutionary who began publicly denouncing him in January 1791. During the Reign of Terror, arrest orders were issued for all of the Ferme Générale, including Lavoisier. On the morning of May 8, 1794, he was tried and convicted by the Revolutionary Tribunal as a principal in the “conspiracy against the people of France.” He was sent to the guillotine that afternoon. The next day, his friend, the French mathematician Joseph-Louis Lagrange, remarked that “it took them only an instant to cut off that head, and a hundred years may not produce another like it.”

Lavoisier experimenting, draw by his wife (who drew herself into the pictue!)

His wife, who had been a key collaborator,  and many of his friends and fellow scientists would make it through the Terror; the unpleasant Marat, the Heydrich of his time, would not. But that’s another story!

Twists of Fate, and Rifling

What separates the winners from the losers is how a person reacts to each new twist of fate.  -Donald J. Trump.

We’re not sure about twists of Fate, but a number of you have asked us about twists of rifling. The question usually comes in the context of AR-15 rifles and their clones, with rifling twists of 1:14. 1:12, 1:9, 1:8 and 1:7 all having been used.

Can you calculate optimum twist for a given caliber and projectile? Yes, you can. There are two equations that are commonly used, Greenhill’s and Miller’s.  Let’s start with the newer one, Miller’s, which was originally proposed in Precision Shooting in March, 2005:

Miller assumes a spitzer-pointed, boat-tailed projectile. In Imperial measurements:

T is twist
30 = a constant representing: standard atmospheric conditions, and a bullet speed of approximately Mach 2 (2800 fps at sea level in standard atmospherics). If you need real precision, Miller does provide more complete equations for that, but these approximations work for rifle velocities.
m = projectile mass, decimal grains
s = gyroscopic stability factor
d = diameter, decimal inches
l =  length in calibers (i.e. length is “l” times the caliber of the projo).

Greenhill’s rule dates originally to 1879, and is frequently used by gunsmiths as it is (or was. anyway) taught as part of gunsmithing school, repeated in Hatcher’s Notebook, and included in Patrick Sweeney’s rifle gunsmithing book among many others. Sir Alfred Greenhill of the Royal Armories at Woolwich developed a number of more complex equations. (More complex than Miller’s, too). But he also provided “Greenhill’s rule of thumb.” Sweeney describes this as follows:

“The length of the bullet in calibers, multiplied by the twist rate in calibers per turn, is 150.”

The constant 150 is good for velocities to about 2800 fps. For higher velocities, as often seen with small-caliber rifles, use 180.

Some notes on twist

As a rule of thumb, the more twist, the more stable the bullet. A bullet must meet a threshold of stability to be accurate. The less twist beyond minimal stability, the less accurate the bullet, in theory, but practical accuracy doesn’t drop off until a bullet is very overstabilized. In small calibers, varmint hunters will tell you a too-fast twist will cause bullets to self-destruct from centrifugal force before overspin hurts their accuracy.

You also need enough excess stability to account for atmospheric changes. As a rule, air density decreases with increased altitude above sea level, and air density decreases with rising temperatures. Less dense air needs less spin than more dense air. This is why the original AR-15 prototypes were found to lose accuracy during Arctic testing by the Air Force — important tests for guys who might have to defend ammo igloos in Iceland, antennas in Alaska, or missiles at Minot. These prototypes had barrels made by Winchester for Armalite in 1:14 twist, then the standard .22x varmint-rifle twist (no one pops prairie dogs in -20F weather). A change to 1:12 solved the problem, at least, for 53-55 grain bullets like those in what would become M193 ball ammunition. (Lighter weight tracer rounds have always been hard to stabilize and trajectory match in 5.56mm). The change to 63 grain ammunition drove the change to a 1:7 rifling twist.

These same calculations may not scale to all types of large-caliber, high-velocity artillery pieces such as tank guns. That’s because air is not truly dimensionless; air molecules don’t scale up as projectiles do. Aerodynamicists and exterior ballisticians can compensate for this scale effect by incorporating Reynolds Numbers in their calculations. For rifle ammo, it’s not necessary or useful.

For those who just want a cheat sheet

Simplified from Sweeney, Gunsmithing Rifles, pp. 109-110

5.56 and other .22 centerfires:

Bullet weight grains Twist ratio 1:inches Velocity
> 70 8 any practical
≤ 70 9 any practical
≤ 63 12 any practical
≤ 55 14 any practical
≤ 55 15 ≥ 4100 fps
≤ 55 16 ≥ 4300 fps

Note that this is really for civilian use in “normal” climactic conditions. For military purposes where you must meet a +140ºF/-40ºF standard, you should go one twist increment slower per bullet weight increment, and understand that you will lose some ability to use weights at the extremes removed from your selected optimum round. Not much of a factor in a military application, where the fewer different DODAAC codes (ammunition stock numbers), the better, as far as the logistics elements are concerned.

7.62 NATO and other .308 centerfires:

Bullet weight grains Twist ratio 1:inches Velocity
> 220 8 any practical
≤ 220 9 any practical
≤ 170 12 any practical
≤ 168 14 any practical
≤ 150 15 any practical

Note again that this is for civilian/sporting/normal-climactic-conditions use.  And that it applies to supersonic rounds only. You must redo the calculations for the slow, heavy bullets used in suppressed applications!

For those desirous of plug-in calculators:

For those desirous of more sheet music:


Cartridges in Transition 1850-80

There’s a traditional understanding that weapons development moved by a sort of punctuated equilibrium through neat phases, like these for muzzleloaders:


And these for cartridges:


But in fact, the conversion from muzzle to breech loader was complicated by a great many factors. For one thing, until it got figured out, nobody had figured it out yet. In that little tautology is wrapped the whole conundrum of how it took about 50 to 75 years for what we now see as the obvious advantages of the centerfire, cup-primed, rimless cartridge to become the modern world standard for service arms, and to drive the earlier systems out of “professional” use, such as big-game hunting, long-range target shooting, military service, and armed self-defense. (Most police service counts in our books as armed self-defense. No officer expects to spend his day shooting people, and most of them retire without ever having done more than cover a suspect with a sidearm).

Impediments to working out “best practices” included the state of metallurgy and manufacturing at the time, the delays caused by patents and patent squabbles, and ultimately, not only the natural ignorance of what those theoretical best practices might turn out to be in practice, but unclarity on and lack of vision of the potential that cartridge firearms would bring forward. (Probably not one in a hundred early cartridge developers imagined autoloading or machine guns).

Most people informed about firearms know that rimfire rounds were developed originally by Flobert and preceded centerfire cartridges by a wide margin. But most people don’t know how similar early centerfire and rimfire cartridges were, or how many other oddball efforts came and went during the years in which those ignition systems fought it out — or why centerfire finally won.

Most people can’t name the first successful centerfire (non-revolver) repeating rifle in the United States, but when they’re told the name, it’s a name they know as an important gun: the Winchester 1873. (Earlier Winchesters, like the Henrys from which they evolved, were rimfires). The initial ’73, in what Winchester called the “Winchester .44 Model 1873 cartridge” that later became known as the .44 WCF or .44-40, was a centerfire gun but it didn’t use either Boxer or Berdan primers. It used a now-forgotten system, the Milbank primer. milbank_primed_cartridgeThe Milbank cartridge had a sheet-brass base soldered to a brass tube; at its center was a primer pocket. The primer, when unfired, had the appearance of a firing pin dent in it already. These rounds were not reliable and Winchester changed to the Boxer system, and the rest is history.

Isaac Milbank’s patent is 93,546 dated 10 Aug 69; Boxer’s is 91,818 dated 29 Jun 69 (but based on his English patent of 13 October 66), and Berdan’s was 82,587, dated 29 Sep 68.

The US Army adopted the Benet primer, an internal primer (and there were other different types of internal primers), for use in the trapdoor Springfield rifles and carbines. Externally, these cartridges have a smooth back, like rimfires. The annular crimp is a give-away.

benet_primedThe cartridges found in cavalry positions at the Battle of the Little Big Horn site were Benet-primed.


As long as centerfire cartridges were flimsy constructions like this, centerfire was not deploying all its arsenal against rimfire. It would be the drawn brass, thick-head cartridge that would make apparent the superiority of centerfire over rimfire, other things being equal.

The armies of Europe were moving ahead, but to single-shot rifles. Intermediate ignition systems like pinfire and needle-fire were prominent in European ordnance circles.

Other oddities like cord and wire extraction were used in some early breechloaders. In these peculiar rounds, there was no rim, but instead, as the name suggests, a cord or wire was provided for pulling the cartridge back out after firing it. The flop-ear or rabbit-ear cartridge used a piece of sheet metal as the extraction hand-hold.

The oddest, though, might have been the annular-fire cartridge. It was an egg-shaped cartridge, rounded at both ends (the front, the bullet, and the back, the rear of the case, fit into a machined chamber). The primer was in a protrusion at the cartridge’s widest point. The Crispin cartridge (shown) was an annular-fire cartridge with a flat back to its casing.crispin_cartridgeThis protrusion made extraction relatively simple. In effect, it was a rimfire cartridge with the rim around the middle — something only worthwhile as a patent end-around.

Ammunition historians tend to lump these early cartridges in together as “metallic primitives,” cousins to the non-metallic “primitives,” cartridges used with muzzleloaders. But while they’re “primitive” today, the rapid fire spray of patents in the 1850s through the 1880s show that they were the high-tech of the era.


Hoyem, George A. The History and Development of Small Arms Ammunition. Four Volumes. Seattle, WA, 1983-1999.

International Armament Association, Inc. A Cartridge Collector’s Glossary, n.d.. Retrieved from:

Tomorrow is National Ammo Day

out of ammoWe haven’t celebrated it in recent years, just because we get buried by events, but 19 November, this and every year, is National Ammo Day, sometimes called National Buy Ammo Day. Your mission, should you choose to accept it, is to buy 100 rounds of ammo. Photos in the comments are a plus!

The minimalist National Ammo Day website explains the event as follows:

November 19 is National Ammo Day.

It is a nationwide BUYcott of ammunition.  You buy ammunition.  100 Rounds a person.

The goal of National Ammo Day is to empty the ammunition from the shelves of your local gun store, sporting goods, or hardware store and put that ammunition in the hands of law-abiding citizens.  Make your support of the Second Amendment known—by voting with your dollars!

Ammo Stockpile

There are an estimated 75 MILLION gun owners in the United States of America.  If each gun owner or Second Amendment supporter buys 100 rounds of ammunition, that’s 7.5 BILLION rounds in the hands of law-abiding citizens!

We think he’s seriously lowballing the number of gun owners here. But getting them all to buy ammo on one day — well, it’s a fond hope, but We Will Do Our Part. And maybe pick up some of all y’all’s slack.

The gun/ammunition manufacturers have been taking the brunt of all the frivolous lawsuits, trying to put these folks out of business.  Well, not if we can help it!  And we CAN help it by buying ammunition on November 19!

National Ammo Day Week

National Ammo Day is on November 19 and that is the day when you mark your calendar. In the text above you may have noticed that we used the phrase “Ammo Day Week.” That is because it is sometimes impossible for someone to get to the store on that specific day to buy ammunition, so we broaden the time when someone may make a purchase, but still have it counttowards an Ammo Day purchase.

So what does count? If you buy ammunition on November 18 or November 20 (the day before or after) does that count? What about November 1 or December 1? These are all questions that have been asked.

Here’s the rule regarding Ammo Day purchases and whether they count: The Saturday to Saturday, constituting a full week. For example: If November 19 fell on a Tuesday, it would be the Saturday before (the 16th), through the Saturday after (the 23rd). November 19 will generally fall somewhere in the middle of that week, unless the 19th is on a Saturday (then, and only then, Ammo Day Week begins on the 19th).

Mirabile dictu, the stars align in 2016 so that National Ammo Day Week begins on Saturday, 19 November. Who knows what ammo lurks in the shops and stores of the nation, like a lost puppy seeking its forever home?

Please, but the ammo today (er, tomorrow) so that we won’t have to have television appeals with sad-looking 7.62 Tokarev rounds, and a voice-over by Sally Struthers. That would be a crime against all humanity and decency.

Note also that National Ammo Day is the Feast of St. Crispin (doesn’t appear to be the same one celebrated by Anglicans on 25 October), and a High Holy Day of the Ventilarian Faith.

British Ammo Improvements

It isn’t just the USA that’s turned away from the 1970s-vintage SS109 round (which is what our 62-grain M855 was, essentially) in pursuit of more accurate ammunition with improved terminal ballistics. The UK has done so, also, although they’ve gone in a different direction from the US.


BAE Radway Green, the Britsh military ammo monopoly contractor, has also improved the venerable 7.62mm round. The British tech ‘zine The Register visited Radway Green and has a rundown on the new ammo — heavy on The Reg’s patented juvie snark, but well-stuffed with technical details.

What’s changed? … It’s all down to penetration – or punching the same depth of hole in ever-better-protected targets.

While RG’s existing products, the 7.62mm L44A1 and the 5.56mm L17A2 cartridges, did that more than well enough when they were originally specified by the Ministry of Defence, modern battlefield technology and techniques mean the military are looking for something with a bit more oompf to fire down their rifles and machine guns.

RG has swapped all-lead bullets for steel in pursuit of better penetration against hard targets – though there’s a lot more to it below the surface.

The two new designs of cartridge, known as the Enhanced Performance (EP) round in 5.56mm and the High Performance (HP) round in 7.62mm, feature new – and, in the HP’s case, heavier – bullets. In addition, the HP round switches from single-base propellant powder to double-base, to give the heavier bullet the same flight characteristics as the old one. The EP also discards the age-old NATO SS109 bullet design, which incorporates a steel tip in front of a lead core, for an all-steel bullet, cased in the same gilding metal jacket as before. Its profile is similar, though.

The genesis for this seems to be the same as that for the US Army and USMC’s newer rounds — technology made better ammo possible. Unlike the Americans, though, the British Army didn’t have to sell the ammo as a “green” boondoggle to social-engineering obsessed Ministry of Defence.

Simon Parker, a project manager at BAE Systems Radway Green, spoke to The Register about the new rounds and the decisions behind the changes in their makeup.

“We wanted to see if we could improve performance against hardened targets. Having a solid hardened steel core improves performance above that of the steel tipped round,” he said. The new 5.56mm round, which will be known as the L31A1 in British service, retains a bullet weight of 62 grains (4g), meaning its ballistic performance will be very similar – an important similarity for soldiers firing it down their SA80 rifles.


For the 7.62mm round, known as the L59A1 in British service, the biggest change is to the weight of the bullet, from 144 grains (9.3g) to 155gr (10g). This increased maximum weight allows the new bullet to incorporate a steel tip, similar to the 5.56mm NATO SS109 design, giving it more mass with which to punch through a light target. Graphs from BAE claim that the HP bullet can penetrate an 8mm steel sheet out to about 400m, whereas its predecessor could only manage it at half that distance.

“We have a standard ball round which is 144gr and a sniper round which is 155gr. The sniper round is manufactured under tighter tolerances and conditions. The 7.62mm High Performance round is not quite the same as the sniper [round] but it’s considerably improved over the standard 144gr bullet,” said Parker.

The propellant in the new 7.62mm round is the same as the 155gr L42A3 sniper rifle round, which is continuing in production. It is a double base propellant – so why the change from single base?

“It’s merely because it’s heavier,” said Parker. “Moving from the 144gr to the 155gr means you need a bit more energy in the propellant. We already use the double base propellant in the sniper round so it’s the same propellant as is used in the sniper round.”

It’s interesting to note that the 5.56 round is Boxer primed, and the 7.62 Berdan primed.

Yeah, but how does it work in the real world? Does it pop hadjis?

“The old Green Spot was just the best lot of ammunition that we manufactured, taken off and marked as Green Spot… but 7.62mm HP would outperform Green Spot,” said Parker.

“We’ve not designed it for a sniper rifle application – though the Special Forces use it as such and that’s fine – but it has been adopted in the sharpshooter rifle [the Army’s L129A1]. It was purchased as a UOR and subsequently adopted. We recommended the use of 7.62mm HP and the user really loves it. But it was originally designed, truth be told, for improved target performance through any weapon system. We made it and designed it so it can be functioned through the GPMG and it’s also being used by the Royal Navy in their Miniguns for defence of ships.”

Do Read The Whole Thing™. The section on the environmental testing that the ammunition endured on its way to acceptance — and that samples must continue to endure — is quite illuminating all on its own.

For more information, BAE Systems has a page on the new ammo, with a rather cool video we were unable to figure out how to embed — so go there to watch it. The ammo has been in production for the UK MOD since 2015, but is now being offered to other military forces.

Boxer and Berdan in Under 1000 Words

In the early days of fixed ammunition, 1840 to 1870 or so, the best way of doing things was far from being settled or self-evident. Many designers worldwide had the same idea: concentrate the primer, powder, and projectile in a single self-contained cartridge. A cartridge could be made of many materials, but whatever it was made of, it offered speedier loading, a simpler manual of arms than any externally-primed system, more ignition reliability, more consistency  from shot-to-shot, and even a small degree of waterproofing. With the advantages so clearly evident, next task was to make the cartridge, and a weapon to fire it. In Europe, pin- and needle-fire arms were up first; in America, rim-fire guns were first.

Pinfire was invented by Casimir Lefaucheux in the late 1820s and 1830s, as an improvement of Prélat & Pauly’s needle-fire design of the early 1800s. Johann von Dreyse, who had worked for Pauly, developed a version of the needle gun that became the Prussian standard, the Dreyse Needle Gun, and the French countered with a needle-gun of their own, the Chassepot. Russia briefly adopted the Karl. All these pinfire or needle-fire weapons would be replaced by centerfire cartridge firearms in good time.

Meanwhile, rimfire, originally developed for the indoor guns of Flobert, was adapted to .22 caliber in the .22 short Smith & Wesson Model 1 revolver. Early rimfire cartridges all used black powder exclusively, but “rimfire” then was not always, as it is now, a synonym for “smallbore.” Larger cartridges than the .22, like the .44 rimfire used in the original Henry rifle, and the .56-56 Spencer, evolved (and weapons evolved to use them). By the end of the Civil War, quite a few Union cavalrymen were armed with breechloading rimfire repeaters.

Centerfire offered advantages over rimfire. It uses less priming mixture, and that, and the central location of the centerfire primer, makes rounds more stable in handling, and also ensures the primer can ignite the propellant more evenly.

The first centerfire cartridges were made much like rimfire cartridges, drawn from thin cups of copper into a thin-sheet construction of uniform thickness, or thinness really, like the familiar .22 rimfire. An internal cup lined the so-called “balloon head” cartridge and had a small cup in it with a place for priming compound, an impact-sensitive fulminate or styphnate of a reactive metal.

For example, the Martin and later Benet cartridges used in the early center-fire Allin conversions of muzzle-loading Springfield rifle-muskets were this type; even the casings recovered at the Little Big Horn were like this. These cartridges were, like rimfires, not practically reloadable. While today, reloading is largely practiced by hobbyists, in the middle of the 19th Century, it was considered beneficial for soldiers and frontiersmen in the remote extents of the American West and the outposts of the British Empire to be able to reload spent casings.


There are two types of priming systems for centerfire cartrifge in use today. Both date back 150 years, to 1866, and in all that time, neither has overcome the other. That is because each one offers specific advantages — the system you choose depends entirely on which advantages you give more weight to.

Each system was developed by a man who had earned the rank of Colonel in his national Army: Hiram Berdan of the United States and Edward M. Boxer of Great Britain. Both were Ordnance officers, although Berdan did distinguish himself in command of a Sharpshooters (skirmishers or light infantry) unit in the Civil War. Boxer was superintendent of the laboratory at Woolwich Arsenal. (Boxer’s family produced many distinguished Army and Navy officers).

Originally, Berdan’s system used a drawn brass case with a heavy, solid head, a primer cup with an integral anvil, and two flash holes in the primer cup set 180º apart. Boxer invented a self-contained primer with its own anvil, and originally intended it to be used in a thin-sheet copper case with a single flash hole on the centerline. The strength advantages of the Berdan case were so evident that Boxer’s system was quickly adapted to the stronger heavy-base drawn case. Berdan had patented his integral-anvil primer pocket, but not the drawn-brass heavy-head cartridge design.


Primer pockets: Berdan (l.) and Boxer (r.)

Accordingly, long before the turn of the century, the only remaining difference was the primer and primer pocket design.

The principal advantage of Boxer’s primers is that they lend themselves to reloading. Berdan’s casings were intended to be disposable. Boxer cases are easily deprimed with a needle that poked through the single larger flash hole. Berdan primers are best deprimed hydraulically, by forcing an incompressible fluid into the case. Boxer primers are also a little more robust and easier to handle than Berdan primers. At an industrial level, it may be cheaper to make Berdan primed ammunition. While making a Berdan case is a little more complicated and costly than making a Boxer case, the complex multipart Boxer primer is an assembly of tiny parts that must be precision manufactured to be reliable. The primer complexity more than offsets the case simplicity.

Primers and Pockets. Berdan (above) and Boxer (below)

Primers and Pockets. Berdan (above) and Boxer (below)

The Boxer system took off in the United States, where cartridge reloading was very common among individuals on the frontier, and where much more ammunition is produced for the civilian market than for the armed forces, and in many more varieties. In Europe, where firearms were more likely to be produced by state arsenals for state actors, in few standardized calibers, the economies of scale justified Berdan priming.

In the US, surplus ammunition with Berdan primers is likely to be corrosively primed, but that is correlation without causation. Either kind of primer can contain a corrosive or a less-corrosive (We don’t think any of them is truly non corrosive) impact-sensitive priming compound. The older the ammo, the more certainty that its primer will leave highly corrosive salts in the bore and action of a firearm, and that’s true of Boxer and Berdan primed ammo alike.

Orbital ATK Gets a Big Ammo Order

Ammo StockpileThis week brought forth two releases from Orbital ATK, the defense giant that spun off its commercial ammo business as Vista Outdoors two years ago to focus entirely on the  government market.

The first release, the one we’re interested in, is about ammo contracts, and it’s good news for OA, if not unexpected. The company will be making over $200 million worth of small arms ammunition for the US Army — enough, perhaps, to relieve shortages of training ammunition, and even enough to get all the combat service support folks qualified without resort to the M1 pencil. We’ll elaborate on the contract in a bit.

OA Today

NYSE: OA on 5 May (sometimes there’s a benefit in a post not being on time at 1100, isn’t there?)

The second one was the quarterly earning call with financial analysts. That one was more of a mixed result; immediately after the 9AM call, OA stock took a header, but it rebounded in the afternoon, and after what looks like a little profit-taking, was actually up by day’s end.

These conference calls are a relative proposition: how well did the company make its number, not absolutely, but in the light of the Wall Street analysts’ average expectations? The good in the call came from the company meeting earnings per share (profits) estimates exactly at $1.31 per share. But even though Orbital ATK revenues were up nearly 10% over last year to $1.06 billion, the analysts had been looking for almost $100 million more, and OA missed that $1.14B target. But that wasn’t all the bad, the CEO dropped a bad-news bit that suggests that the company hasn’t met “synergy targets,” from the ATK-Orbital merger, and says he’s still looking for $30 million a year in cost savings — not good news if you’re an employee there, because that’s a target on your back.

OA is a complex company that does everything from launch a few colossally expensive satellites every year, to manufacturing billions of 5.56 rounds   for the US Armed Forces and America’s Foreign Military Sales customers.

The ammo contract press release says:

Orbital ATK, Inc. (OA)… announced today that it has received orders totaling $210 million to produce small caliber ammunition for the U.S. Army. Orders were placed for .50 caliber, 5.56mm and 7.62mm ammunition under Orbital ATK’s supply contract to produce a variety of small caliber ammunition for the U.S. government at the Lake City Army Ammunition Plant (Lake City) in Independence, Missouri.

“This latest order continues a long history of supplying only the best ammunition to our warfighters,” said Kent Holiday, Vice President and General Manager of Orbital ATK’s Small Caliber Systems division of the Defense Systems Group. “Every round is produced with the highest quality because we know that those defending freedom depend upon the good work of our employees.”

Orbital ATK has operated Lake City for the U.S. Army since 2000, during which approximately 15 billion rounds of small caliber ammunition has been produced to support U.S. and allied warfighters around the globe. During the past several months, Orbital ATK and the U.S. Army have been making upgrades and investing in state-of-the-art, high-volume technology to enhance the efficiency and cost-effectiveness of the facility.

As the press release suggests, the Army owns the plant, but Orbital ATK (and its predecessor, ATK) operate the plant under contract to the Army.

One annoying detail: the contract contains a 2005-vintage clause[.pdf] that requires Orbital ATK to destroy any leftover ammunition, parts, components rather than sell them to the public.

There’s a rumor going around that the new contracts are specifying steel rather than brass cases. That seems unlikely; from what I’ve seen of these contracts, they’re just refills of the same old ammo.

Steel cases promote action and barrel wear, which has been demonstrated in tests. We doubt that it is due to a single mechanism, but we expect it was principally because of poor obturation. The guy that invents something that gives better obturation than good old brass is going to create a revolution in ammunition — assuming that it has other properties that beat the old golden stuff.

How Stripper Clips were Made in 1916

When the world was in arms, and the arms were bolt-action, the essence of “rapid-fire” reloading was the stripper clip. While a few nations (notably the Habsburg Empire) use Mannlicher en-bloc clips, most of  them used Mauser-type strippers. After encountering the superior Mauser rifle in the Spanish-American War, the US took steps towards adopting a Mauser-derived rifle (which would ultimately yield the 1903 Springfield and its .30 caliber ammunition). As an interim measure, America experimented with a stripper-feed option for the .30 service rifle, the .30-40 Krag-Jorgenson. Only 100 Krag rifles and 100 carbines were made with the so-called Parkhurst device in 1899; this one sold at Rock Island Auctions in 2010.

Krag Parkhurst Device

Hmm. Here’s a side view:

Krag Parkhurst Device 2

The Parkhurst Device is a forgotten footnote to firearms history, but the procedures developed to manufacture and load stripper clips had arrived in the arsenals just in time for the adoption of a stripper-loaded firearm, the M1903 Springfield rifle.

For a simple assembly of metal, the manufacture of the stripper was fairly complicated:


Let’s see what a period (1916) book had to say about manufacturing these clips.

Making Cartridge Clips. —The device for quickly inserting cartridges in the magazine of a 0.30-caliber rifle consists of a clip * which holds five cartridges sufficiently tight to prevent them from falling out. As soon as the clip is placed over the breech and the top cartridge pressed, they are ejected and pass into the magazine. The clips are thrown away when empty, so that they must be made very cheaply. The main body of the clip is made from a sheet of brass stock about 0.021 inch thick by 2 7/16 inches wide. The sequence of operations necessary to complete this clip is illustrated from A to G in Fig. 3, and the machine for making the body of the clip is shown in Figs. 4 and 5.


Referring to Fig. 4, which shows a front view of the press, the strip stock is held on a roll located at the right-hand end of the machine. The stock is fed into the machine by the ordinary type of feeding rolls, and the first operation is to cut out a blank as illustrated at A in Fig. 3. This is accomplished by the punch and die B, see Fig.5.


The blank is then ejected from the die and carried on to the next punch and die D and E by means of a transfer slide C similar to that employed in a multiple plunger press, that receives its motion from a crank mechanism at the left-hand end of the machine. The next operation, performed by the punch D and die E, is to form two ribs in the center of the blank, and turn up the two edges as shown at B in Fig. 3. The formed blank is then ejected and the transfer arrangement carries it on to the next operation, where punch and die F and G crimp the outer edges into the shape shown at C, Fig. 3. The edges of the blank are flattened down and at the same time turned up a distance about 3/64 inch above the top surface of the blank. The blank is then ejected from the die and is carried forward over die H. As punch I descends it forces the blank out of the transfer fingers and into the die H, This operation forms four projections which are shown at D in Fig. 3 that act as retainers for the spring to be inserted later. The next punch and die J and K draw up the sides of the clip into a box shape as at E, Fig. 3. Then, as the blank is passed on to the last punch L and its die, it is slightly curved and is ejected from the machine by a crank mechanism N, Fig. 4, which actuates the last die. This sequence of operations is carried on entirely automatically, and, in fact, the machine will run without any attention whatever until the roll has been exhausted. The operator then starts up the machine and the sequence of operations continues.


Making the Spring for the Cartridge Clip. —In order to hold the cartridge in place in the clip, a curved flat spring F, Fig. 3, is used. This spring, which is made from a sheet of half hard brass stock 0.510 inch wide by 0.010 inch thick, is blanked out and bent to shape in the press shown in Fig. 6. The stock is held on a roll A shown to the left of the machine, and is drawn in by a pair of ordinary feeding rolls B operated by a ratchet mechanism receiving power from the crankshaft of the machine. The first operation is to cut off a strip to the required length, form the ends, and pierce the three holes. This blank, by means of a carrier, is then transferred to the punch and die C. Here the blank is bent up into a curved shape and the spring prongs at each end are formed, after which it is ejected. These prongs are used in assembling the clips for holding the spring in place; they catch on a projection formed in the base of the clip. This machine is also entirely automatic in its operation, and, when once started, it will run until the roll of stock has been exhausted.


Assembling the Spring in the Cartridge Clip. —The assembling of the springs in the cartridge clip is accomplished in the small bench machine shown in Fig. 7. The operator places the clip in a nest, then inserts the spring in a slide which carries it forward and inserts it in the clip. The spring is held on this slide and is pushed into the clip automatically by the prongs which fit into the raised catches in the clip. The clip is carried forward into the assembling position by another slide, which works beside the spring-inserting plunger, and operates a carrier D, In order to show the working mechanism of this machine, the top lid or plate that covers the mechanism has been removed, and is shown to the right of the illustration. The clip is inserted through the hole A, and the spring in the hole B, When the operator pulls the handle C, the slide advances carrying the spring and assembles it in the clip. After assembling, the clip is ejected from the machine and drops into a box placed beneath it. The assembled clip appears at G in Fig. 3.

Gee, that looks like a mind-numbing job to us. And one easily automated. (It probably was, soon after 1916). The “machine” in this case is real Model T-era technology, a device that processes one part at a time and is powered by human muscle.

At this juncture, we have completed stripper clips, and elsewhere in the same book (see Source below) the entire process of completing ammunition, practically from raw materials, has been described and illustrated in similar depth and detail. What remains, then, is to inspect, clean and load the cartridges into the stripper clips. Onward!

Gaging, Weighing, and Inspecting Loaded Cartridges. — Before locating the cartridges in the clip, they are inspected, gaged, and weighed. These three operations are all accomplished in one machine, which is shown in Fig. 8.


As you can see, this is another highly manual process. Note that in 1916, a century ago, there was no statistical quality control: every single round was subject to inspection. (Despite that… all the grenaded Springfields from Wednesday’s post?). We’ll continue with the explanation of what we’re seeing in Fig. 8 above.

The dies held in the dial A in which the cartridges are placed by the operator act as a gage for the body of the cartridge; that is, the contour of the holes in these dies is similar to the chamber of the rifle. As the dial passes around, the cartridges are carried beneath an electrically operated plunger which inspects them to see that each one has a primer in it. Should a cartridge be encountered that has no primer, this punch drops down into the pocket and breaks the electric circuit, which causes a bell to ring, thus notifying the operator that a cartridge with no primer has passed. When the primer is located upside down, the same action takes place. The cartridge is weighed in a unique and interesting manner. As the dial A passes around, the cartridge is lifted up and caught by the ejector B. This transfers the cartridge to the scoops C which are carried on the weighing dial D. The weighing is done by balances E in which the cartridges are deposited by the scoops C. The bullet comes up to a stop in these balances and a wire hook attached to the balance catches on the wire F when the cartridge carries the correct charge of powder and dumps the cartridge into the box G. When the charge of powder in the cartridge is light, the hook on the weighing balance E rides up over wire F, but as the dial passes around still further the hook catches on a wire located higher than wire F, and dumps the cartridge into the light charge box. It is therefore evident that cartridges which are light in weight pass the first box, but cannot go completely around, as they are ejected by the second wire, thus making certain of dumping the weighing balance and throwing the cartridge out. This mechanism successfully eliminates all light charge cartridges, and keeps them uniform in shooting quality.

That’s a bit of a Rube Goldberg machine, but there doesn’t seem to be any method of catching a heavy load. It is probable that a normal load filled the casing nearly brim-full and therefore a heavy load was not possible, practically.

Now it’s finally time to stuff the cartridges into the clips.


Inserting Cartridges in the Clips. —The machine used for inserting the cartridges in the clips is shown in Figs. 9 and 10. A dial A, which accommodates five cartridges in a row, carries the cartridges around to where the clip is inserted over them. This dial is rotated by means of a crank motion, pawl and ratchet in the ordinary manner, the ratchet dial being located beneath the dial carrying the cartridges. The assembled clips are placed in the proper position in the magazine B by an operator; two operators are engaged in keeping the cartridge dial full. The clip is carried out from the bottom of the magazine by means of a carrier operated by an eccentric shaft, and is located over the five cartridges in the dial A. The ‘”latch” C which is shown thrown back in the illustration runs under a roller held in bellcrank D and seats the clip properly on the heads of the cartridges. The dial then indexes to the next position, where a bending tool comes into action and bends down the prong projections on the ends of the spring in the clip, thus preventing the cartridges from dropping out. As the dial then indexes around to the next position, the cartridges that have been inserted in the clips are picked up out of the dial by means of a swinging transferring arm that drops them in a box; 65,000 of these cartridges are inserted in the clips per day of eight hours. Fig.10 shows a closer view of the machine illustrated in Fig. 9, and gives a better idea of its construction and operation. Here it will be seen that the ejecting or work-removing fixture is composed of two pieces of sheet steel, spring tempered, which grip the clip by the lower surface.

* The term “clip” has been used here, as that Is the name used by the U.S. Army; this part, however, should be properly called a “charger.”


It would be interesting to compare this line to how Mauser’s guys were doing it in Teutonistan, but we’re not aware of any analogous German source.

This is a chapter of a 1916 book, Cartridge Manufacture, by Douglas Hamilton, who was then Associate Editor of the trade magazine Machinery. (We’re looking for Hamilton’s other works in ebook or hard copy, including “Shrapnel Shell Manufacture.”

Complete bibliographical information — and perhaps of more immediate use to you, a .pdf of the document, courtesy Microsoft Corporation — follows.


Hamilton, Douglas T. Cartridge Manufacture: A Treatise Covering the Manufacture of Rifle Cartridge Cases, Bullets, Powders, Primers and Cartridge Clips, and the Designing and Making of the Tools Used in Connection with the Production of Cartridge Cases and Bullets, Together with a Description of the Principal Operations in the Manufacture of Combination Paper and Brass Shot Shells. New York: The Industrial Press, 1916.

Available here: cartridge_manufacture_hamilton_1916.pdf  (12.4 MB .pdf file, color).

Don’t Forget Forgotten Weapons…

… although, it could be called “Remembered Weapons,” because Ian remembers all the stuff that everybody else has forgotten. True, we haven’t flagged you to his site in, what, two whole days? But when he’s posting stuff like this, you need to be over there, not here. We’ll still be here posting several times a day, but trust us, you want to see these two posts, and you want to point your RSS reader at FW so you never miss stuff like this.

Item: The Grandpappy of all MGs

Every gun begins with the prototype — no, wait… Every gun begins with an idea, but it has to pass through the stage of prototype if it’s ever going to be made concrete and marketed, adopted, and/or produced. And Forgotten Weapons is starting a new series on the Maxim, the grandpappy of all machine guns, with a great post on the prototype, which is, naturally, the granddaddy of all Maxims.


One of the best parts of that post is a video Ian scared up which shows the ur-Maxim’s inner cuckoo clock. It’s ingenious, but it’s fair to say that the highly developed Maxim of the First World War was vastly simplified and improved over this design.


That, of course, just makes the engineering dead ends of the prototype even more interesting. There’s a little bit of similarity to the much later aerial weapon, the Mauser revolver cannon, in that a rotary sprocket is used to lift the cartridges after they are withdrawn by an extractor from the ammunition belt.

Item: Small Arms Development, 1945-65: the Soviet View

Victory Day parade. Rather than rest on their laurels, the Soviets overhauled their weapons after World War II, and by 1965 they'd done it a second time.

Victory Day parade. Rather than rest on their laurels, the Soviets overhauled their weapons after World War II, sending these Mosins to the warehouse, and by 1965 they’d done it a second time.

Ian got hold of a fascinating primary source document: a CIA translation of a classified Soviet analysis of small arms development after World War II. Both the intent of Soviet development and the differences between Soviet and NATO small arms doctrine and development objectives are laid bare in this document (available at the link).

Our long-held thesis that Soviet developments were primarily focused on putting automatic fire in the hands of their riflemen, whereas Western forces primarily focused on aimed semi-auto fire, is borne out from the horse’s mouth, as it were. The authors of the piece, two senior Soviet officers, see, from their point of view, 1965 NATO as making a serious error in not giving their riflemen weapons that can be effective in automatic fire at close range. Of the US Army:

[E]xperience in the operation of the M14 rifle has shown that it has extremely unsatisfactory grouping capability during automatic firing, as a result of which it is assigned to US troops only in the semiautomatic variant.

…in recent years the American army has renovated nearly all of its small arms. However, it should be pointed out that with the NATO cartridge as a basis, the USA has failed to solve the problem of developing a mobile and effective automatic individual weapon that satisfies the requirements of modern combat. For this reason the Americans have taken measures to modernize the M14 rifle, to explore other rifle designs, to develop a new 5.6-mm cartridge with reduced power, and to develop a rifle that will use this cartridge.

Ivan also prized light weight in his weaponry.

With allowance made for [the Soviets not being sure what NATO armies carried as a basic load of ammunition -Ed.] the average weight load (weapon plus unit of fire of cartridges being carried) per man amounts to: in the Soviet Army — 7.2 kilograms, in the US Army — 9.3 kilograms, in the West German Army — 10.9 kilograms, and in the French Army — 8.5 kilograms,

(This is referring to the M14 version of the US Army, the one that faced Russian occupation armies in Eastern Europe directly at the time. Elsewhere in the report, they note the emergence of the M16 as something to be watched).

Judged on the basis of these data, the weaponry of the Soviet Army is the lightest. This has been achieved by the use in our army of the 7,62-mm Model 1943 cartridge and the development for it of an automatic rifle and a light machinegun, which have made it possible to substantially lighten the weight of both the individual weapon itself and also the unit of fire carried with it.

Interesting to us that no credit at all is given to the Germans for inventing the intermediate cartridge and assault rifle concept. While the CETME rifle is mentioned as the source of the German G-3, there’s no mention that the CETME itself is an adaptation of the StG.45. (That fact may have been unknown to the Russian authors).

The authors were extremely satisfied with the state of Soviet weapons, and considered their weapons superior both individually to their counterparts, and on a unit vs. unit basis.