Category Archives: Scattered Shots

Updated – Safety Bulletin for the Ruger Precision Rifle

New Ruger Bolt Shroud

I received a replacement bolt shroud from Ruger yesterday.  The new bolt shroud is on the left, the original on the right.

If you own a Ruger Precision Rifle, I would highly recommend you check if your rifle falls under the safety notice.  If it does, get the replacement bolt shroud.  It is not good to have a firearm that might not fire when you need it and worse might fire when you don’t want it.

The Ruger Safety Bulletin can be found here.


Continue reading Updated – Safety Bulletin for the Ruger Precision Rifle

Zero your damn MRDS.

Before zeroing the pictured mini red dot sight, it was impacting 4 feet high, and a foot right at 50 yards.

Some time back I really got into the piggy back mini red dot sight (MRDS) on top the ACOG.  I’ve also run them on top and offset from higher magnification scopes.

So having started running these offset and piggyback MRDS, I got really curious about how other people were using them.  So I asked people, in person and on gun forums.

“Oh, it’s for close range, so it’s not zeroed.”

Now to be fair, there was one person who said he zeroed his at 10 feet.  All the rest had their mini red dots unzeroed.

The point of a firearm is to be able to place rounds on a desired target.  Be that target a piece of paper, prey, or a hostile combatant, we index our firearm on the target in order to achieve that effect on target.  We use our sights to verify that the firearm is aligned and indexed with the target.

It is pointless to have an unzeroed optic.

“But Howard, I’m only going to use the red dot at super close range.”

At close range is there it is most important that your shots are effective.  If you have a less than ideal hit on a bad guy 500 yards out and they take a few minutes to bleed to death, that would just be a shame.  But if up close you fail to instantly neutralize a target, the result could be deadly for you, or those you care about.

The big downsize to having these secondary miniature sights is odd height over bore or offset issues.  These issues can lead to these offset sights being massively off, like the one pictured above.  Offset sights are usually sitting on a stack of mounts attached to a handguard that may or may not be parallel with the bore.  It can be very easy to be multiple feet off target at close ranges with an unzeroed offset sight.  Your average sight on an AR15 is 2.6 inches over the bore.  A piggy back red dot can easily be 4+ inches over the bore.  This height over bore makes picking a good zero difficult.

There is going to be a part 2 to this article, where I will go over some of your options when zeroing an offset or piggyback MRDS.

Best of Weaponsman Come for the Shovels, stay for the Swords

This is another re-post in our own going tribute to our now gone friend  Kevin, AKA “Hognose” owner of  weaponsman now missed by many . We will continue to put up Kevin’s excellent work as a back up to ensure it is saved.

Come for the Shovels, stay for the Swords

Swords and sword-fighting are a long time issue of ours, and once we’ve gotten past our amusement with the Russian and Russophile fascination with shovel fighting, we know that the art of sword fighting was once the peak of combat effect, and it seems obvious that the best guides to that art would be found in historical materials from that period.

Of course, sword-fighting never went away from popular culture, and it’s been a staple of Hollywood for nearly a century. But one has an instinctive feeling that Hollywood’s choreographed swordfights are as phony as their fist- and gun-fights; and that they’re doing it wrong. Sword expert J. Clements of the Association for Renaissance Martial Arts agrees in a long essay:

It is the stuff of Hollywood sword-fights and renaissance-faire fight shows: a swordsman cuts with his or her blade and in defense the opponent lifts their own sword to directly receive the blow at 90-degrees on the center of their blade. The two blades clash in the middle edge-on-edge with a loud “clang!”  There is just one problem. No two cutting-swords—historical or replica, authentic or modern, Asian or European —would withstand such abuse without their edges being severely gouged in the process. This is a problematic issue of historical fencing exploration that can be addressed reasonably and factually.

When it comes to historical swordsmanship, such a description stands in direct contrast to how edged weapons were actually handled and employed. It contradicts the very dynamic of effective and efficient fighting and resembles little in the way of sword combat described in Medieval and Renaissance fencing literature.

via Edge Damage on Swords.

He goes on at rather great length about the historical sources, so it’s worth reading the whole thing. But here’s another taste:

In the chronicle of the deeds of the 15th century knight, Don Pero Niño, we read how in a fight against the Moors, “the blows fell upon good armour, though not so good but that it was broken and bent in many places.  The sword he used was like a saw, toothed in great notches, the hilt twisted by dint of striking mighty blows, and all dyed in blood.”  At the end of the siege of the City of Tuy in 1397, we are also told again how Niño’s sword “blade was toothed like a saw and dyed with blood.”  Later, Pero Niño sent this sword by a page to France, “with other presents to my Lady of Serifontaine.” (De Gamez, p. 196.)  Given the context of this description, where Nino’s shield, armor, and sword are all damaged from especially heavy fighting, it would not seem unreasonable that he then gives his ruined sword away as a token of his chivalric courage. Certainly, we have no way of knowing if his sword edge was damaged from striking armor and shield rims or from striking other blades, let alone from parrying cuts (something less likely if he had a shield and full armor as described).  Regardless, the recognition that Nino’s sword edge had sustained heavy damaged so that it looked “like a saw” and was “toothed in great notches” from use is indicative that such a condition was certainly not a good thing for a functional blade. Above all, he did not enter combat with his prized weapon in such a condition.

Yes, that’s one single dense paragraph in the original.

Now, perhaps some of this is the well-known tendency for martial arts entrepreneurs to see no merit in, and consequently trash-talk, their competitors. An example which seems to be Clements doing just that is here.  But Clements’s approach of going back to period sources is to be commended. There is a great deal more information on the site.

HURSTWIC is an organization which takes a similar approach, not to the combat of the 13th through 15th centuries but to the earlier Viking era. Theirs, too, is an approach that combines archival research (in this case, in Norse sagas, mostly) with athletics. Compared to Renaissance and even medieval European sources, of course, Viking primary sources are few and this gives rise to some problems of interpretation. A page on Sword and Shield Combat Technique is one of many restatements of this problem on the Hurstwic site:

[W]e don’t really know how weapons were used in the Viking age. We don’t have any material that teaches us how Vikings used their weapons. The best we can do is to make some educated guesses based on a number of sources, as described in an earlier article.

This article summarizes some of the fighting moves we believe were used by Vikings when fighting with sword and shield. Not surprisingly, as we continue our research, my opinions on the nature of Viking-age combat have changed. Our interpretation of the moves is always in flux. So, please be aware that the techniques illustrated in these web articles may not always represent our most current interpretation. Notably, in the past, we have depended more heavily on the later combat treatises than we currently do. That bias remains in this and other articles on the Hurstwic site. We plan to edit the articles to reduce those biases as time permits and as our research unfolds.

Our most current interpretation is outlined in the article on the “shape” of Viking combat and illustrated by several videos on that page showing fighting moves from the sagas.

That article s found here and it is fascinating to watch the Hurstwic team grapple with these mysteries, to understand ancient armed combat, as they have only a few sources. Even these few have their limits: the sparse descriptions in the sagas, the known characteristics of Viking weapons, and their own powers of logic. Their own opinions have changed as their knowledge has grown, which is inevitable in a scientific approach to almost anything. They are keenly aware that their scientific approach rests on a foundation of assumptions, but what they’re doing is extremely interesting.

About Hognose

Former Special Forces 11B2S, later 18B, weapons man. (Also served in intelligence and operations jobs in SF).

WTF Autoglove?

So I was just informed about the “Autoglove”.

Picture taken from their website, click on the picture to visit their website.

It is a glove with some sort of electronic plunger to press a firearms trigger for you quickly.

First, stuff like this goes to show how stupid our gun laws are.

Secondly, you have to be impressed with how the free market will come up with a solution to any perceived problem.

Third, I am very curious if this will actually be approved by the ATF or not.  Previously they did not allow for the electric actuating of triggers.

I wouldn’t recommend this thing to anyone.  I believe you would quickly see shooters lose control of weapons with it.  What we really need is this unconstitutional NFA act abolished so silly law work arounds would be unnecessary.

Arms Unlimited Shipping

I work at a company that makes a great product at a good price.  We pack our product individually in padded envelops in a cardboard box.  That is one thing I think is rather hokey and could be done in a way that would look a great deal more professional.  One of our competitors sold their product in a box with custom cut foam.  I think that made their product look to be high end.  Now they replaced that with shrink wrapping their product to a piece of cardboard.  Now that cheap, crappy looking, and is just annoying for the customer.

I recently made a purchase from Arms Unlimited.  They have some good prices and they are now also offering a knock off of the Norgon ambidextrous magazine catch for the AR15.

I was very disappointed when I received the parts I ordered loose in a USPS shipping bag.  The bolt carrier groups, gas tube, and forward assist that I ordered were all scratched up from rubbing against each other.  Not very impressive.

But, I did get what I needed, and with any luck I’ll have a review of the Arms Unlimited Norgon knockoff for you guys soon.

Firearms Reverse Engineering : Best Of Weaponsman

Since the passing of our friend Kevin, AKA “Hognose”  we have been  running a “best of” spot of Kevin’s articles.   Best of being a bit of a misnomer as every thing he wrote qualifies.   We will continue posting Kevin’s writing as a tribute to him and an effort to make sure it always exists some where as  we are alive .


Firearms Reverse Engineering

One thing about the people of the gun: we’re conservative. By that, we don’t necessarily mean that we want 15 carrier groups back, eager to cut taxes and services, or sorry that mandatory chapel was gone by the time we went to college. There are actually card-carrying ACLU members and ivory tower socialists among us, but they’re conservative about their guns. For every reader who’s up to date on polymer wonder pistols, there’s about three who wish you could get a new Python. (The reason they can’t is that they don’t want it $3,500-4,000 bad, which is what an old-style hand-made perfect Python would cost to make today). Or a new Luger. For every one of you guys following the latest in M4 attachments (hey, let’s play “combat Legos!”), there’s a few who’d buy a new MP.44, if they could.

Every once in a while, gun manufacturers decide to satisfy these consumer yearnings with product. Sometimes, they succeed. Sometimes, the 10,000 guys who told them they were down for a semi-auto Chauchat turn into 10 guys who buy one and the businessmen get to undergo the intensive learning lab called Chapter 7 bankruptcy. The question becomes, if you are raising a zombie firearm from the dead: how? Even the original manufacturers tend not to have prints and process sheets for >50 year old products, and if they do, the documents are ill-adapted to the way we do things now. If your original product was made in Hiroshima or Dresden pre-1945, or Atlanta pre-1865, odds are the paperwork burned. If the company went tango uniform even ten years ago, rotsa ruck tracking down the design documents.

So, you’re sitting here with a firearm you know you could sell. You have the rights to reproduce it, because any patents and copyrights and trademarks are either in your possession or expired or defunct. Your problem is reverse engineering. It turns out that this is a very common problem in the firearms industry, and the path is well beaten before you.

Some Examples of Reverse-Engineered Drawings

People can do this with some calipers, a dial indicator, and some patience. Rio Benson has done that for the M1911A1.

Screenshot 2015-04-03 09.58.55

He explains why he thought a new set of documents were necessary in a preface to his document package:

Historically, when the drawings for John M. Browning’s Colt M1911 were first created, there was little in the way of ‘consensus’ standards to guide the designers and manufacturers of the day in either drawing format or in DOD documentation of materials and finishes. For the most part, these were added, hit or miss, in later drawing revisions. Furthermore, due to the original design’s flawless practicality and it’s amazing longevity, the government’s involvement, and the fact that in the ensuing 100-plus years of production the M1911 design has been officially fabricated by several different manufacturers, the drawings have gone through many, many revisions and redraws in order to accommodate all these various interests. These ‘mandated by committee’ redraws and revisions were not always made by the most competent of designers, and strict document control was virtually non-existent at the time. All of this has led to an exceedingly sad state of credibility, legibility, and even the availability of legitimate M1911 drawings today.

He modeled the firearm using SolidWorks 2009, with reference to DOD drawings available on the net, and his own decades of design and drafting-for-manufacture experience. The results are available here in a remarkable spirit of generosity; and if you want his solid models or his help producing this (or, perhaps, on another firearm), he’s available to help, for a fee.

findlay-stenIn a similar spirit, experienced industry engineer David S. Findlay whom we’ve mentioned from time to time, has published two books that amount to the set of documents reverse-engineered  from an M1A1 Thompson SMG and from a Sten Mk II. The limitations of these include that they come from reverse-engineering single examples of the firearm in question, and the tolerances are based, naturally, on Findlay’s experience and knowledge. So his reverse-engineering job may not gibe with the original drawings, but you could build a firearm from his drawings and we reckon the parts would interchange with the original, if his example was well representative of the class.

Nicolaus M1 Garand bookOn the other hand, Eric A. Nicolaus has published several books of cleaned-up original drawings of the M1 Garand, the M1D, the M1 and M1A1 carbines, various telescopes, etc.

Nicolaus’s books provide prints like the Findlay books do, but they’re not reverse engineering. They’re reprints of the initial engineering, cleaned up and republished. Not that there’s anything wrong with that.

Sometimes the Industry needs Reverse Engineering

A perfect example is when planning to reintroduce an obsolete product. Most manufacturers that have been around since the 19th Century never foresaw the rise of cowboy action shooting, but now that it’s here, they want to put their iconic 1880s products in the hands of eager buyers. Or perhaps, they need to move a foreign product to the US (or vice versa). In this case, reverse engineering the product may be less fraught with risk than converting paper drawings which use obsolete drawing standards, measures and tolerancing assumptions. You may recognize this reverse-engineered frame:


If you are exploring a reverse engineering job, there are several ways to do it. The first is in-house with your own engineers. (You may need to ride herd on them to keep their natural engineers’ tendency to improve every design endlessly in check). The next, is to outsource to an engineering consultancy that does this. The third is to use a metrology and engineering company, like Q Plus Labs, from whom we draw that pistol-frame example. They say:

[W]e offer numerous reverse engineering methods and services to define parts or product. Q-PLUS provides everything from raw measurement data to parametric engineering drawings that correspond to a 3D CAD solid model! We also offer reverse engineering design consulting to point you in the right direction.

  • Digitizing & Scanning
  • Measurement Services
  • 3D CAD Solid Modeling
  • Engineering Drawings

In other words, you can go there to have them do, essentially, what Rio Benson did with the 1911 with your product. They can digitize an item from 3D scanning, or they can take a drawing and dimension it from known-good examples. Given enough good examples, they can actually determine tolerances statistically and substantiate them to a level that will satisfy regulatory agencies such as the FAA. (This lack of a range of parts and statistical basis for the tolerances is, in our opinion, a rare weakness in Findlay’s single-example approach).

Reverse engineering has gone from something in the back alleys of engineering or attributed to overseas copycats, to something firmly in the mainstream of modern production engineering.


About Hognose

Former Special Forces 11B2S, later 18B, weapons man. (Also served in intelligence and operations jobs in SF).

How low will they go?

$360 dollar AR15 for sale here.

Prices on guns are at an amazingly low price.  I know that gunshops I have talked to are hurting for sales.  Now is really the best time to buy if there is something you want, and a terrible time to be selling.

To paraphrase a quote, “The problem with being in a golden age is that you don’t know it is a golden age when you are in it.”  Take advantage of this time while it lasts.

A Short History of Chrome Bores

Again this week we have a post from our friend Kevin O’Brien, owner and author of  Kevin AKA Hognose, passed away earlier this year and in a back up effort we will be running  “The Best of weaponsman”  which could be every technical article he  wrote. 


For some 500 years it’s been known that rifling would impart spin and therefore stabilization to a ball or bullet. Spiral grooves probably evolved from straight grooves only intended to trap powder fouling; by 1500 gunsmiths in Augsburg, Germany, were rifling their arquebuses. This gave rise to an early attempt at gun control, according to W.S. Curtis in Long Range Shooting, An Historical Perspective: 

In the early 16th Century there are references to banning grooved barrels because they were unfair. Students of the duel will recognize this problem arising three hundred years later.

Curtis, 2001. Curtis notes that why rifling was twisted is unknown, and that it may have been incompletely understood. He has quite a few interesting historical references, including one to a philosopher who explained that if you spun the ball fast enough, the demon (who dwelt in gunpowder, which was surely Satan’s own substance) couldn’t stay on and guide your ball astray. (Curtis’s work is worth beginning at the beginning, which is here).

By the mid-19th Century, the Newtonian physics of the rifled bore had been sorted out, the Minié and similar balls made rifled muskets as quick-loading as smoothbores, and the scientific method allowed engineers to test hypotheses systematically by experimentation. So smoothbores were gone for quite a while (they would return in the 20th Century in pursuit of extreme velocities, as in tank guns).

Rifling had several effects beyond greater accuracy. It did decrease muzzle velocity slightly, and it did increase waste heat in the barrel. The first of these was no big deal, and the latter was easily handled, at first, by improved metallurgy. But rifling also helps retain highly corrosive combustion by-products in the bore; and corrosion was extremely damaging to rifling. Pitted rifling itself might not have too much of an effect on accuracy (surprisingly), but the fouling that collected in the pits did. Corrosion also weakened the material of barrels, but most military barrels had such great reserves of strength that this was immaterial, also.

Fouling and pitting have been the bête noire of rifles from 1498 in Augsburg to, frankly, today. A badly pitted barrel can only be restored by relining the barrel, a job for a skilled gunsmith with, at least, first-class measuring tools and a precision lathe with a long bed. Relining has never been accepted, to the best of our knowledge, by any military worldwide.

Chrome Plating is Invented: 1911-1924

One approach has been to use corrosion-resistant materials for barrels, but that has been late in coming (late 20th Century) because it is, of course, metallurgy-dependent. Early in the 20th Century, though, American scientists and engineers developed a new technology — electroplating. George Sargent, of UNH and Cornell, worked with chromium as early as 1911, and Columbia scientists developed a commercially practical process of using electrodes to deposit chromium by 1924. Meanwhile a New Jersey professor worked with a German process.

The two groups of professors formed start-ups, the Chemical Treatment Company and the Chromium Products Corporation. At this point, chrome plating has not been applied to firearms. Electroplating had been used for guns for decades, of course, but that was nickel plating — eye-pleasing, but soft and prone to flaking, not suitable for bores, and not remotely as corrosion-resistant as chromium.

(This article is rather long, so it is continued after the #More link below. We next take up the application of this process to rifle bores).

Chrome comes to bores in the lab: 1925-32

One thing that had held chrome plating back was lack of a practical quality control method. George Dubpernell discovered a practical test almost by accident: chrome would adhere to copper, but copper would not adhere to chrome. This was later supplanted by NDT methods, but it was essential to the growth of chrome in industry.

Olin’s and Schuricht’s patent of 1932 (not 1935, a rare error in Emerson),  US Patent 1,886,218, applied chrome plating to small arms and sporting weapons’ bores. They applied for the patent in 1927, and note, as is now well known, that bores must be made slightly oversized to account for the dimensional changes from chrome deposition. They also, interestingly, saw chrome plating as a way to restore worn rifling and eroded barrels. We’re unaware of any such use being brought into practice in the intervening decades.

Meanwhile, in 1937, T.K. Vincent noted that:

Chromium plating of small arms barrels results in longer accuracy life. However, the cost of plating is excessive compared to the results obtained.

The longer accuracy life results from taming the bugbear of bore erosion. By 1942, in a thorough study of bore erosion of guns large and small (from 3″ naval guns to small arms),  Burlew noted a report by Russell that considered chrome plate a “bad” material from a bore-erosion standpoint, except “when made very adherent”; in that case it was an “excellent” material, roughly five to nine times better than ordinary plating. Chrome-plated steel barely edged out bare steel, and all beat exotic metals like Inconel and Monel; the least erosion was found in the chrome-plated barrels with the thinnest chrome plating (0.0005″), although all these tests were of a 12″ naval gun, and their applicability to small arms might not be direct or proportional.

The technology of chrome plating continued to advance, even as weapons designers struggled to bring the technology’s benefits to bear on practical small arms.

Adoption of chrome by the world’s militaries — early adopters

The Empire of Japan was the earliest nation to chrome the bores of its rifles. The Japanese had different reasons, perhaps, than other nations. In Japan, supply of high-quality steel was insufficient to wartime requirements. This is especially true after 1940, when the United States imposed sanctions on the island nation, which depended on imports for almost all resouces; and even more true as unrestricted submarine warfare, which was ordered implemented even as the Pearl Harbor strike force was recovering on their carriers, began to strangle the home islands.

Casting about for a way to work with the second-rate steels they had, the engineers at Sagami Arsenal, which was used for ammunition storage and for war production (Japan’s only 100-ton tank was built here; it was too heavy to move to the seaport for deployment) set upon a 1937 patent. They concluded that chrome-plated mild steel could substitute for some high-speed and high-carbon steels, and from 1940 that’s what Japanese engineers did. The history of a Japanese firm explains:

The Japan Science Council reported then Government to recommend the policy to apply hard chrome plating on the low grade steel as the alternative to high grade one, such as special steel or high-speed steel, under the difficult external trade conditions to get them, the invention, Patent No.131175 (1937), “the method to deposit hard and thick metal chrome plating” by Minoru Araki, the former president of Company, being as the technical foundation. It was followed by the request to establish a specialized company of hard chrome plating (industrial chrome plating) from National Headquarters of Aviation, Sagami Arsenal, and customers.

As a result, the next rifle adopted by Japan, the Type 99 Arisaka 7.7mm rifle, had a chrome-plated bore. As David Petzal writes for Field and Stream, they were “the first military barrels ever to have this feature.”

The industrial and materials-science reasoning behind Japanese chroming is missing from most US sources. Gordon Rottman (a fellow SF veteran) writes that , “the Japanese had the foresight to produce the type 99 with a chrome-plated board to prolong barrel life, ease cleaning, and protect it from tropical rust.”

In addition to the Type 99s, all of which were intended to be made with chrome-lined bores, all Type 100 submachine guns, some late Type 38 6.5mm Arisakas, and some late Type 14 “Nambu” pistols had chrome-lined bores. By late in the war, ever more serious materials shortages meant that chrome bores were one of the features deleted from late production guns (like such Type 99 features as a monopod).

The United States initially chromed only large-caliber artillery bores. From

In the 1930s, the USN started to chrome plate the bores of most guns to a depth of 0.0005 inches (0.013 mm). This was “hard chrome,” which is not the kind that you find on your father’s Oldsmobile. This plating increased barrel life by as much as 25%. The plating generally extended over the length of the rifling and shot seating. Chrome plating has also been found to reduce copper deposits.

All along, as a large body of scientific papers at DTIC reveals, US small arms developers continued to work on chrome for small arms. US engineers were aided in this by their very great extent to which chrome was being used in the automotive industry. Springfield Armory developers would have had access to many papers being produced at the same time by the SAE, and Springfield of course worked closely with the developers, themselves, of chrome industrial processes.

But chrome was not standardized for US small arms bores until after World War II — in fact, not until the mid-1950s, well after Japanese and Russian adoption of the technology. As we’ve recounted here before, the first US weapon to be manufactured new with a chrome bore was the M14 rifle. Around the same time, chrome bores were used in developing a 7.62 mm NATO conversion kit for the Browning light machine guns, and replacement barrels that were manufactured for Legacy weapons like the M1 rifle, started to be manufactured with chrome bores as well.

Because chrome bores lost some definition in the rifling, and therefore some accuracy, National Match rifles continue to be produced with standard bores. But the advantages of chrome in the field could not be overlooked.

The M16 rifle was initially produced without a chrome bore. There are two reasons for this: first, the M16 was a product of a private industry initiative, and not the usual Army development system. The disastrous fielding of the M-16, with the bare bore combined with very poor maintenance practices and some units, led to the Army adding a chrome chamber, and then finally a chrome bore to the weapon.

Another assembly of the M-16 was chromed, and this led to a lot of problems. The part in question was the entire bolt carrier group. Early on, a number of the bolts and bolt carriers failed. This turned out to be due to metallurgical problems, specifically with heat treating (that will sound familiar to anyone who has followed the M14 history), the deficiencies of which were masked by the plating, and also with hydrogen embrittlement of the steel carrier during the chroming process. The specification was changed to require the bolt to be Parkerized, except for its internal expansion chamber, and the inside of the bolt carrier key, which are still chromed (chroming only a single surface of a part does not risk hydrogen embrittlement).

Early chrome BCGs that were properly heat-treated and passed testing were allowed to remain in M16A1s by the Army, but they were not allowed to be deployed OCONUS. The reason given (in the M16 maintenance manual, TM9-1005-319-23&P) is simply to prevent glare off a chrome bolt carrier from exposing soldiers’ positions.

The USSR‘s reasons for introducing chrome plating (whether for corrosion control, ease of cleaning, or metallurgy) are unknown to us, but extensive collector interest makes it clear when the feature was added: 1950. No known 1949 SKS or AK rifles have chrome bores, some 1950 models do, and almost all 1951 and subsequent guns do. Chinese AK and SKS rifles were produced with chrome bores from their introduction in 1956. Some satellites’ bores were not chromed, notably Yugoslavia’s pre-1970s. (Yugoslavia was technically not a “satellite,” but it was a Eurasian communist country).

For practical purposes, this means that all Soviet and Chinese spec AKs will have chrome bores. In addition, gas pistons are also chromed. This greatly facilitates cleaning, and prevents corrosion in a highly corrosion-prone part of the system.

Russian small arms of larger caliber, including the 37mm tube of the RPG-7V, are also chromed.

Adoption of chrome by the world’s militaries – later adopters

Belgium, a small country that looms large in world firearms exports thanks to FN, was not an early adopter of chrome bores. The entire production of the FN-49, including all ABL, SAFN, and AFN rifles, left the FN factory with conventional steel bores. Much later, metric pattern FALs received, first, chrome chambers, and later chrome bores. What makes FN interesting enough to comment on here is their  use of chrome extended to the internal parts of their MGs and the insides of their receivers, making MAGs and Minimis very easy to clean.

US variants of these FN guns don’t have these parts chromed. The initial MAGs and Minimis purchased using using special funding vehicles by select US special operations units, had these features. In subsequent US production, the chroming was eliminated, and those parts of the M240 and M249 are Parkerized. We don’t know if this was done to save money, because the Army simply preferred the Parkerized coating, or because of the Army’s bad experience with chromed bolts on the M16A1.

Britain adopted chrome bores well after World War II, including some retrofits like the L4 Bren Gun from at least the L4A4 version to the final L4A9. As noted above, Britain’s inch-pattern FALs did not receive chrome bores.

Chrome chamber vs Chrome bore

Industrially speaking, each of these had its own pros and cons. Chroming the whole barrel was more expensive, increased demands for both manufacturing and inspection precision, required the rifling to be cut slightly oversize (to allow for the chromium deposition), and led to much greater waste. Chroming the chamber was a compromise that enhanced extraction — a sticky problem with many automatic arms — without the costs and problems associated with full-length bore chroming.

But the US experience showed that half a loaf (chroming the chamber only) didn’t get the job done. While the chamber became very resistant to corrosion, GI’s inspection of the bore often stopped with a glance in the chamber area, and if the chamber was gleaming, they’d assume the rifle was good to go — eveb as combustion byproducts and deposits ate away at the rifling.

Meanwhile, chrome bores let the manufacturers do things that were difficult or even impossible with conventional manufacturing processes. As noted above, the Japanese were able to use chromium plating to substitute for lack of chromoly steel. In the USA, Springfield Armory discovered that by slowly withdrawing the barrel, chamber first, from the chromium bath they could create a squeeze-bore effect due to the higher deposition of chrome on the parts of the barrel that were in the chrome bath longer. (Methods of altering the depth of chrome depositions produced at least two patents, 2,425,349 and 2,687,591; the second is Springfield’s process).

Chrome’s cost rises

In the 1970s, the chost of chromium suddenly went through the roof: the two greatest producers, Rhodesia and the USSR (ironically, two defunct nations, today) were locked out of the US market, the former by sanctions and the latter by international politics. (Note that around 1974 the styles of American cars began to use less chrome plate and more body-colored and black molding. This fashion was driven in part by costs).

Today, the biggest driver of rising plating costs is new environmental regulations. Chromium, like most metals, is something you really don’t want to breathe in.

Quality chrome plating is still expensive, and cheap plating produces a lot of waste. Some gun parts makers have chosen to, essentially, ignore the waste and ship products with poor (or zero!) nondestructive testing and inspection, sacrificial sample examination, or other valid QC.

Chrome plating today & tomorrow

Plating has to fight to maintain its place vis-a-vis other anticorrosion technologies, including noncorrosive metals (i.e. stainless steel) and superior steel coatings like Melonite, but it has a very strong position as an erosion fighter, particularly in barrels subject to high temperatures (think automatic fire).

Some scientists are working on electroplating as a means of additive manufacturing. Laugh if you like, but the plating industry of today was entirely based upon laboratory discoveries.

And gun engineers continue to apply new kinds of chromium treatment to bores. A recent patent application by Rheinmettal covers depositing a different thickness of chrome in the lands and the grooves of a rifled barrel.

One of the biggest changes is that a chrome-plated bore, if made with sufficient care, may be as accurate or more accurate than a bare bore. (For example, SAK manufacture M16 replacement barrels seem to outshoot many target barrels). But this may not be as big a change as you think. According to Emerson, in 1962 Springfield Armory made a small quantity of chromed National Match barrels. They discontinued the practice not because the barrels were bad, but because they were much more expensive to make than bare barrels, and they were not any better. But they were atdid fully comply with national match standards at the time.

Chrome-lined barrels are currently the standard in military small arms. This will change if and when something better comes down the pike – and not before.


Burlew, John S. The Erosion of Guns, Part One: Fundamentals of Ordnance Relating to Gun Erosion. Report No. A-90 Progress Report. Washington: National Defense Research Committee, 8 Sep 42. Retrieved from:

Burlew, John S. The Erosion of Guns, Part Two: The Characteristics of Gun Erosion. Report No. A-91 Progress Report. Washington: National Defense Research Committee, 31 Oct 42. Retrieved from:

Curtis, W.S. Long Range Shooting, An Historical Perspective. Research Press, 2001. Retrieved from:

Dubpernell, George. History of Chromium Plating. Products Finishing magazine, 13 Nov 12. Reprint of Plating & Surface Finishing from 1984. Retrieved from:

Emerson, Lee. M14 Rifle History and Development. Online Edition, 2007. Sagami Depot, Japan. n.d. Retrieved from:

Koka Chrome Industry Ltd., Company History. n.d. (2011 or later). Retrieved from:

Olin, John, and Schuricht, Alfons. Gun barrel and process of finishing the same. Washington, 1932: US Patent No. 1,886,218. Retrieved from:

Rottman, Gordon. Japanese Army in World War II: the South Pacific and New Guinea, 1942–43. 2005: Osprey Publishing. (p. 36).

US Army, Technical Manual: Unit and Direct Support Maintenance Manual (Including Repair Parts and Special Tools List): Rifle, 5.56mm M16A2; Carbine, 5.56mm M4; Carbine, 5.56mm M4A1. Washington, DC, 9 Apr 97

Vincent, T.K. Development of Chrome Plating of Guns. Abstract only (have been unable to find the full text). Aberdeen Proving Ground: Ballistics Research Labs, 1937. Retrieved from:

About Hognose

Former Special Forces 11B2S, later 18B, weapons man. (Also served in intelligence and operations jobs in SF).