Category Archives: Ammunition

Understanding CZ Test Targets

In accordance with longstanding European gunmaker custom, CZ ships a test target with its pistols. These seem ridiculously simple, but there are enough people asking about them in online forums that we thought we’d explain them. We usually have a few CZs with boxes and paperwork around the house…

Don’t get too excited, they’re not NIB old stock (well, most of them aren’t). (If you look real close to the right of the CZ-75 box, you can see a current CZ-UB box that almost exactly matches the black background. Adventures in photography). While we don’t have anything from the 70s or earlier represented here, we do have (oldest first):

  1. A CZ vzor 70 in 7.65 mm manufactured during the pistol’s production twilight, in 1980.
  2. A CZ-83 in 7.65 mm manufactured during the pistol’s production startup.
  3. A CZ-75 “Pre-B”, manufactured in 1987, prior to mass importation to the United States;
  4. A CZ-75 P-01, manufactured in 2015, which is typical of current CZ-UB production.

The first three pistols were manufactured during the Cold War era and the P-01 is contemporary. All four were probably scheduled for production with a view to exportation, although both the vz. 70 and the P-01 were also the standard pistols of the national police force, and when this CZ-83 was made, there was some thought that the Verejna Bezpečnost (police) would adopt it order to retain the 7.65 caliber.

It is our understanding that all targets are shot rapidly, from rest, at 25m, although only some targets are labeled with distance; and that Sellier & Bellot ball ammunition is customary.

We’ll now look at the targets in the same order. The targets are of three different types: the vz. 70 has a small polygonal aiming point inside a rectangular target area, the target used by the CZ-75 and -83 has a rectangular aiming point with the center of desired impact on its bottom edge and a circle centered on that point descrining the desired impact area, aand the P-01 target is a modern digital rendering of the firearm’s performance on an instrumented range.

  1. The vz.70 target is actually labeled vz.50. This makes perfect sense, as the two pistols have only cosmetic differences; most of the running changes in these small police pistols were made during the vz. 50 years. A late vz. 50 is more like a vz. 70 than it is like an early vz. 50. There are six shots on the target, one a flyer to the left. The legend at top reads: PISTOL 7.65 MODEL 50 and PISTOL NUMBER 652090. The legend on the bottom reads DATE: 29 Dec 1980; SHOOTER: Zemek (with two partial, illegible rubber stamps, one circular and one a signature), and OTK with a rubber stamp which may be the “kissing lips” we discuss below. We would welcome any insight to the meaning of the acronym OTK, but suspect it’s some type of inspector.
  2. The CZ-83 target is a CZ-75 target with the -75 legend scratched out with black ink, and a CZ-83 legend rubber-stamped in place. Whether a specific target was developed for the CZ-82/83 series is unknown; it’s possible, as this pistol has a four-digit serial number flagging it as first year production. The CZ-75 would have been the main export product of the Uhersky Brod plant when the -83 was introduced, and these targets would have been in daily use. On this target, the pre-printed CZ-75 lines (which you can read on the next target) are inked out, and a rubber stamp says Pistol čz model 83 caliber 7.65 mm. Below the inked-out CZ-75 lettering is Distance 25 m, and to the right is Pistol Number 002846. The legend on the bottom reads Date (blank) Shooter (stamp looks like JBICHR [?]), and OŘJ with a stamp we call the “kissing lips” but appears on magnification to be a blurred-out stamp that once had numbers or characters within it. It seems logical that OŘJ also refers to some inspector or inspection title, but again we do not know the Czech acronym.
  3. The target with the 1987-production CZ-75 (pre-B, which dates to 1992) is the same basic one used for the CZ-83 above, obviously without the CZ-83 adaptations. The legend inked out in the -83 target is seen to read PISTOL ČZ Model 75, Caliber 9 mm Parabellum, and the SHOOTER stamp at bottom center reads FICE[?]NC. The OŘJ stamp can be seen to be a circle with illegible characters inside (we liked it better when we thought it was kissing lips! From Moravia with love!). Seven shots appear to have hit this target, unlike the six of the two earlier ones. It is possible that this target is more “weathered” than the older CZ-83 target because the gun reached its end buyer in 1987, while the CZ-83 remained in one warehouse or another until 2017.
  4. The P-01 is a modern computerized target that depicts the fall of the shots graphically on an ordinary sheet of A4 computer paper, and contains a great deal more information than the old targets. There is no point in translating any of the Czech, as CZ-UB has helpfully done it for us. This target represents the impact of five shots by white circles. The blackened circle is the calculated center of the group.

That the new targets are labeled in English as well as Czech is a nod to CZ’s export focus these days; printing them on an ordinary A4 sheet of computer paper and generating them by computer saves time and money at a busy factory, yet gives buyers confidence that their firearm has been tested and worked. (Europeans still have to proof-test their firearms, but we suspect many American firearms leave factories without every cycling a live round).

The Cold War era targets are (sparsely) labeled in Czech only, and are printed on extremely coarse and flimsy Warsaw Pact era paper, which has, as you can see here, yellowed to one degree or other with age. They do have a certain character. If we didn’t want to keep these in the boxes the firearms came in, we might just frame them. How much of the dirt, oil etc. on these fairly dirty targets came from the range and how much from the intervening decades of handling is anyone’s guess.

All targets are serial numbered to the guns, usually with blue ballpoint ink, and have a space for the technician who fired the gun to stamp his name and the date. Both of these stamps are seldom present, but the serial number has always been.

One open question is whether targets like these were furnished with domestic police and military firearms. Our tentative hypothesis is that they were not; instead, the military (etc) acceptance stamp went on when the ordnance officer was satisfied, and there was no point in retaining a target beyond that. None of the CZs we have with Czech military or police acceptance marks came with targets, but all were used (most, well-used) when we acquired them.

Update

We thought that we’d add this: if you’re lucky enough to have a date stamp on your CZ test target, the month will be abbreviated in Czech. Here is a table of the Czech months and the standard abbreviations for those months, which CZ used on its stamps.

Czech Months

English month Česky (Czech) ČZ Abbreviation
January leden led.
February únor ún.
March březen břez.
April duben dub.
May květen květ.
June červen červ.
July červenec červen.
August srpen srp.
September září zář.
October říjen říj.
November listopad list.
December prosinec pros.

Watch out for June and July!

More on the Czech/German AT Rifle

Our recent auction post reminds us that (1) we have to come up with some better way of flagging more interesting auctions and (2), and more to the point of this post, that there’s a lot of interest and misconceptions about the Czech-German AT rifle featured at one upcoming auction.

First, this 2015 post here has some background on rifle-caliber-yuuuge-case AT rifles, like the German and Polish variants, and their rounds. (This archived external page also covers the round). The Germans chambered this rifle in their standard wartime 7.92 x 94 mm P318 round, which was used in the standard German PzB 38 and 39 AT rifles. The round was capable of 4,000-plus fps from a long barrel and the most common ammo was a tungsten-cored kinetic penetrator. P.O. Ackley, eat your heart out. Barrel life was pretty short, but if you’re going to shoot a rifle at tanks, it’s not the life of the barrel that should be worrying you.

(The Russian site that cartridge picture is from appears to be down now, unfortunately).

Those rifles operated by a dropping block, like an artillery piece (or early breechloader), and their principal mechanical difference was that the PzB 39 was manually operated, replacing the “semi-automatic” (in artillery terms) automatic opening and ejecting of the PzB 38.

The Czech rifle used completely different principles, and as proposed for Czech service a different cartridge.

In fact, the Czechoslovak Army experimented with a variety of anti-tank rifles in the 1930s, as part of a campaign to improve AT defenses overall. Many Czechoslovak officers put their faith in conventional anti-tank artillery, but others pursued the AT rifle. Many versions were tested including Josef Koucky’s’ ZK 382, a bullpup repeater which fired a unique 7.92 x 145 mm round, further ZK single-shots ZK 395 (12 mm x ?) and ZK 405 (7.92 x ?), the ZK406 repeater and 407 self-loader the “Brno W,” the Janeček  9/7 and 15/11 mm Gerlach-principle squeeze bore, and several 15mm designs, including vz. 41 single shots, and a bolt-action magazine repeater which was supplied to Italy (in only 15 units) and possibly Croatia. The 15mm guns used an AP version of the 15 x 104 mm round used in the Czechoslovak vz. 60 heavy MG, produced primarily by the British under ZB license as the 15mm BESA. The Czech engineers then reworked into the vz 41 in 7.92 x 94 for the occupiers, specifically, for the SS.

During all this experimentation, Czechoslovakia was dismembered and its Czech provinces occupied. The best was the enemy of the good; nearly a decade of experimentation in AT rifles wound up yielding absolutely nothing for the Czechoslovak Army. (It was a moot point, perhaps, as despite its strengths in tanks and artillery, there was no resistance to the Nazi occupation.

Most of the elite of the Czech arms design industry worked on these rifles at one time or another. Vacláv and Emanuel Holek worked with Koucky at Zbrojovka Brno; Jiri Kyncl worked with Janeček.

By the time the SS received their rifles, they were already hopelessly outclassed by improved armor, and among Speer’s actions in his attempt to rationalize the chaos of the German and occupied territories’ arms industry was to discontinue production of the 7.92 x 94 Type 318 ammunition.

The M.PzB.SS.41 was supplied in a wooden transfer and storage crate containing the rifle, two spare barrels, and four magazine boxes containing five magazines each. There were some variations in minor features (bipod, muzzle brake) during production. Of some variants, only photographs or documents survive. We have found no reports of combat effectiveness.

All of these AT rifles are rare today, the German guns existing in single-digit quantities (the mass-produced PzB 39s were recalled during the war and converted to grenade launchers, the GrB 39).

Sources

  • Dolínek et al. Czech Firearms and Ammunition: History and Present. Prague: Radix, 1995.
  • Hoffschmidt, E.J. Know Your Anti-Tank Rifles.  Stamford, CT: Blacksmith Publishing, 1977. (A .pdf of the chapter of this out-of-print book on this rifle is attached: MPZB41 comp.pdf)
  • Šada, Dr. Col. Miroslav. Československé Ruční Palné Zbrane a Kulomety. Prague: Naše Vojsko, 2004. (pp. 139-142, 197-198).

Update

Well, this is embarrassing. Never hit “schedule” or “publish” on this one. -Nose

Update on the FK Brno 7.5

We have written about this pistol before, but it’s had a long and arduous trip to market, and it’s still not really here. It may finally be coming (and here’s another allegation of imminence from four months ago). In any event, we haven’t got hands on one yet — hell, we haven’t seen one for sale, but we’ve found a couple of articles by people who have handled the gun, not just the press releases. And of course, there’s the manufacturer’s website.

Despite the inventors’ denials, and the gun and ammo’s own unique technology, it clearly owes a great deal to the CZ 75 and its descendants. (That’s not a bad thing, necessarily. After all, everybody owes a great deal to the M1911 and its descendants, too). The lockwork seems similar to the precision-oriented CZ single-actions.

The pistol is manufactured conventionally, for a Czech firearm. That is to say its components are CNC milled from billet or from investment castings (possibly by Poldi, which has cast for ZB and CZ since CZ-Strakonice days, before CZ built the UB factory  in 1936).

Unique ghost ring FK sight.

But the FK Brno 7.5  offers a unique high-velocity round, a unique buffer system, and unique sights. The FK 7.5 pushes .30 caliber copper bullet at 2000 feet per second, not quite rifle speed, but better than such remarkable rounds as the long-defunct .357 Auto Mag. Its numbers make the .357 SIG look like it has the parking brake on.

 

It’s otherworldly enough to generate considerable skepticism. When the FK 7.5 first came up on the radar last year, John Zent of American Rifleman noted its sudden appearance on the market had a certain “out-of-nowhere” quality. John Roberts a Guns, Holsters, and Gear also was unimpressed by the claimed velocity, because it can be matched by a 9mm firing an ultralight 50 grain round — delivering half the FK 7.5s energy.

An FK 7.5 shortslide prototype photographed by Rob Pincus at the factory.

Here is celebrity trainer Rob Pincus, with what he promises is Part I of a multipart article. Rob was invited to the Czech Republic to try the gun during its long period in ATF purgatorio, and has some interesting comments.

A High Capacity Handgun that fires a propriety [sic] 100 grain round at over 2000fps and costs over $5000. The round, by the way, is still moving at 1500fps at 100 meters… which is the distance at which the pistol is zeroed with a unique set of sights when it comes from the factory. As others in the above links note, the gun is relatively large, fires a very powerful round and isn’t going to be cheap. FK BRNO also claims that the gun is very controllable and capable of high levels of precision. And, the only guns currently in the USA are there for government evaluation so that importation could be approved.

Per Pincus, the company considers itself primarily an ammunition research company, which builds the pistol as a way to get its ammo concept into shooters’ hands. He hits these takeaways — and elaborates on each, so you’ll want to Read The Whole Thing™:

  1. FK BRNO says that they are an Ammunition Company that also makes a handgun.
  2. FK BRNO set out to develop a handgun that delivered AK-47 performance in regard to Terminal Ballistics at ranges between 50 and 150 meters.
  3. The 7.5 round delivers high levels [of] precision.
  4. The Terminal Ballistics are even more impressive than the precision capability.

He concludes: “FK Brno have done what they set out to do.” We’ll say again, Read The Whole Thing™, and we’re looking forward to the next part.

The tactical niche this pistol fills is unclear, although it seems to overdo what the Secret Service and Federal Air Marshals Service selected the .357 SIG to do. It is, without doubt, a magnificent engineering accomplishment, and the prototypes seen so far are beautifully finished. One clue is that, in its native country, it is available in a folding shoulder-stocked version, making it a near-peer of PDWs like the HK MP7 and FN P90 / FiveSeVen combination. It also appeals to people who love that kind of engineering for its own sake.

If it’s a success, it will seem less strange in due course. If it’s not a success, it will be a footnote to firearms history of near-GyroJet proportions. Either way, we want one!

Name That Round!

Hey, don’t be surprised if it throws you. It sure threw us, and we thought we knew guns and ammo!

Need a hint? It’s .30 caliber, and a bit of a Frankenstein monster with a rebated rim and a sharp shoulder.

Need another? It was created as a deer-taking round, gerrymandered to fit a unique state law.

Give up? Explanation after the jump.

Continue reading

US M17 Pistol Comes with Ball and Hollow-Point Ammo

From Mark Miller we learn the following:

According to Jane’s “The US Army has confirmed that its new XM17 handgun is to be a 9 mm Sig Sauer model P320 and the contract allows the government to buy Sig Sauer’s proposed XM1152 Full Metal Jacket (FMJ) and XM1153 Special Purpose (SP) ammunition and training rounds.”

The secret to making (new) 9mm outperform (existing) 9mm, which the RFP required, was, per Mark, “hollowpoints.” Presumably, the XM1153 is the holllow-point, and the 1152 an improved ball round. The actual RFP also requires numerous oddball rounds like blank and dummy.

It’s interesting that SIG introduced new hollow-points last year, and new ball ammo in 125 and 147 grain at this year’s SHOT Show.

Mark’s conclusion:

While the P-320 is a great choice for the M-17, we may find that hallow point ammunition makes a much more significant contribution to U.S. defense than their gun.

He’s probably correct there.

Mark’s site, The Arms Guide, is becoming a regular stop on the net. Check it out.

 

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:

http://www.jbmballistics.com/ballistics/bibliography/articles/miller_stability_1.pdf

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:

black_powder_model

And these for cartridges:

cartridge_model

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.

Julia-auction-Trapdoor_BigHorn_14

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.

Sources

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: http://cartridgecollectors.org/?page=glossary

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.