Category Archives: Rifles and Carbines

3D-Printed 9MM Semiauto (video rich); 3D Guns Update

As we have expected to happen for some time, and as the initial Cody Wilson “Liberator” first demonstrated, 3D-printed firearms made of common addititive-manufacturing plastics like ABS or PLA inevitably had to diverge from common steel firearms practice to take advantage of those plastics’ strength — and overcome their weaknesses.

That means that, while early prints were nothing but, for example, a plastic version of an AR lower dimensionally identical to its aluminum forbear, but destined for a short life (especially in PLA), more and more designs are innovating in different directions.

This series of videos shows the Shuty, a 9mm pistol based on kitbashing the designs of British homemade gun pioneer P.A. Luty and the AR-15 together. It uses several metal parts, including the barrel (which comes from a Glock 17), the fire-control group (AR), and the bolt (home-made). On the other hand, the magazine, upper and lower receivers, and bolt carrier, are all printed from a polymer generally thought unsuitable for firearms parts. Turns out, you can design around materials deficiencies (as the Japanese did when they used chrome bores for strength, to offset the suboptimal alloys they had for rifle barrels, decades before other nations adopted them for durability, and when their aeronautical engineers designed assemblies built-up of  7075-equivalent alloy sheet where every other skyfaring nation would use a 7075 forging).

Here is Derwood’s working Shuty, redesigned from the original, as of 1 May 15:

He says:

After several failed attempts with the Shuty, I decided to beef it up to handle the stress. The combination plastic/steel bolt works very good. After several test fires, the frame and lower is holding up well and no damage has occurred.

The plastic parts were all printed on the SeeMeCNC Orion printer, an entry-level machine, in PLA (polylactic acid), the entry-level printing material that is biodegradable and derived from renewable resources. The bolt assembly looks complex, but:

Its just three steel dowels stacked and welded together parallel with each other. the bottom smaller dowel is drilled for the firing pin. the center dowel is a spacer. the top dowel is the buffer.

Fosscad (an informal, leaderless, cellular homemade-3D-gun resistance) picked up the video and Fosscad user ma deuce posted it on 22 May 15. (Link only because it’s basically the same video, why embed it?)

Here’s Derwood’s next video, 20 May 15, showing a longer test fire. What appears to be a jam at the end isn’t, actually; what it is, is the bolt gnawing on the magazine spring because this work in progress doesn’t have a magazine follower yet — just a spring pushing the cartridges up! Oy.

Well, if you’re going to crib something, cribbing Glock’s feed ramp by using their barrel is a short cut to a working firearm. Glock reliability is not accidental, it’s a product of careful design and iterative improvement.

So that brings us to 27 May 15. It’s fully working, with firing and a mag change, two eight-round mags complete:

Derwood says it’s still evolving, and not finished yet; when he thinks it’s “finished,” he’ll release the .stl files. Until then, he tinkers on at a high rate of speed.

As a practical 9mm pistol the Shuty has its limitations. It gives you all the firepower of a Kel-Tec belly gun in a platform the size of what it is, a mongrel of AR-15 and MAC M10 ancestry. It has no sights, no stocks, and is only slightly more concealable than a basketball. Made of PLA, the stuff used in the dishes microwave dinners come in, it’s destined for a short life, by gun standards (we’ve got guns one and two centuries old here). So, as a practical pistol? A turkey. But as a proof of concept, it is enough to get would-be totalitarians “all wee-wee’d up” (in the locution of one such).

Ah, but bolts? Barrels? Too early to write about, but people are working those issues.

Some Other 3D Developments

Of course, the Shuty is far from the only 3DP pistol in development. Here one is with the Imura revolver (left) and the Songbird pistol (center):

Imura Songbird Shuty Redesign

Joel Leathers of Texas even posted the .stl files for the Glock 17 on Thingiverse. (That link 404s; the files were deleted, due to MakerBot’s political anti-gun position, but there is a story on PrintedFirearm.com. At least they didn’t unperson Joel on Thingiverse. Yet).

Glock-3_preview_featured

Of course, a printed Glock part will not be usable in a firearm as is. But we can see practical uses for the files. (How about a printed, brightly colored, safety barrel for use in mechanical training? Pennyslvania State Police?)

How has this technology progressed so fast? Some of these guys print a lot. This printer has racked up nearly two months of run time, and used over six miles of filament!

Some of these guys print a lot

This is a 10-22 with receiver and trigger housing printed. We’ve discussed this project before. (Indeed, that story from last month has a photo in it which is a crop of the one below).

10-22 with major parts printed

We’ve shown the receivers before, but here are some printed trigger housings.

10-22 trigger housing printed

AR receivers continue to be developed. This heavily-reinforced AR-10 lower design, the Nephilim (an obscure Biblical reference to a purported race of human/angel crossbred giants) by Warfairy, shows

AR10 Nephilim by Warfairy

Here at Hog Manor, we’re still on the waitlist for our printer.

If You Build It, Nanny Wants to Ban It

Banning this sort of thing is very tempting to anti-gun lawmakers, political appointees, and those executives in the ATF who see the agency’s mission as “to destoy gun ownership.” Indeed, some of the European nations with fewer checks and balances hindering their legislative range of motion have already banned this kind of experimentation.

The problem with that, is that it is but a short step from the Shuty to a select-fire submachine gun. If you drive this design activity entirely underground, the designers are as well hung for a sheep as a lamb, no?

The largely-libertarian tinkerers making these things are doing no harm to a society, and may do some good. They have no sympathy with criminals who would use this technology to harm or threaten people. But let that be the line the law draws in the sand: not the malum prohibitum “if you make this we will hammer you,” but the malum in se “if you do harm with this we will hammer you, and the maker community will help us find you.”

VPO-208: Russian Gunsmiths Respond to Russian Law

We’re familiar, here in the USA, with weapons that are shaped by US gun laws. We have a variety of weird and wonderful arms that exist only because of the Gun Control Act of 1968, the National Firearms Act of 1934, and the patchwork of implementing regulations and executive orders that have shaped the US market. In addition, state assault-weapon band have resulted in oddities like California’s “Bullet Buttons.” A wide range of legislatively-midwifed Frankenguns, from the Walther PPK/S, to short barreled rifles, to pistols with SIG braces, reflect the degree to which designers are constrained by the gun-designing impulses of American politicians and bureaucrats.

It should come as no surprise that the same thing happens in other countries with large gun markets. This case in point comes to us from Russia, where gun laws are generally stricter than in the United States. There, no one can own a pistol. Most citizens can own a shotgun; but to own a rifle you have to have owned the shotgun without incident for five years.

So here comes the VPO-208: an SKS shotgun.

SKS in .366Produced by Techcrim, an Izhevsk manufacturer, the .366 by Russian measure, across the lands (.375 by ours, across the grooves), is a smoothbore or near-smoothbore gun that gets the would-be gun owner into a semi-automatic, service rifle platform, while staying within the letters of Russian law.

The ammunition appears to be made from fireformed 7.62 x 39mm casings, and is available in a range of sporting projectiles, plus a shotshell variant.

It is reminiscent of such American wildcats (some of them since turned production) as the small-head .300 Whisper, .300 AAC Blackout, .338 Spectre, and the Mauser-head-sized .375 Reaper, all of which run in the AR-15 platform. It just goes to show that this kind of innovation is hardly an American monopoly.

The first table in the advert below has three columns: “Type of projectile”; “Speed, meters per second;” and “Energy, Joules”. Here’s our conversion of this table.

Projectile Type Velocity, m/s Energy, J Velocity, fps Energy, ft-lb
LSWC poly coat 13.5 grams 640 2765 2099 2039
FMJ 11 grams 700 2618 2296 1931
FMJ 15 grams 620 2883 2034 2126
JSP 15 grams 620 2883 2034 2126

Techkrim

 

As the shot of the fired JSP shows, and these velocity and energy tables suggest, it would actually be a good short-range hunting round.

The second table, with the bullet-drop diagram, is, “Velocity and Energy of Projectile, .366 TKM with 15-gram FMJ bullet”. Here’s our translation and unit conversion.

Metric (SI) Values Muzzle 50 meters 100 meters
Bullet Drop mm 0 35 125
Velocity m/s 625 570 520
Energy J 2837 2437 2028
English Values Muzzle 50m 100m
Bullet Drop in. 0 1.38 4.92
Velocity f/s 2050 1870 1706
Energy ft/lb. 2092 1797 1495

The problem with the gun is its accuracy, as it’s basically a smoothbore. Hyperprapor suggests that it might be minute-of-E-silhouette at 100m.

But hey, it will let some Russian guys own the rifle their nation’s color guards parade with, and even let them shoot it, all with the reduced paperwork and hassle of a shotgun; perhaps a big win for them.

There are no ballistics for the shotshell, which exists, we suspect, primarily to navigate the channels of Russian weapons law. (This law does seem somewhat liberalized since Soviet days). Techcrim’s website shows that they are very active in small-caliber (.410) shotguns and shells, which seem to have more of a following in Russia than they do here. We wonder if that’s an artifact of Russian law, too.

We saw this on r/guns, posted by our old friend hyperprapor, who notes that under Russian law “paradox rifling”  is legal if it’s under 150mm long (About 5.9″).  Paradox rifling is rifling that was just engraved in the last few inches of the bore of what was otherwise a shotgun, to give it some capability with a single ball or bullet. It was named by English bespoke gunmaker Holland and Holland, who adopted the patent from GV Fosbery of Webley-Fosbery fame. Westley Richards called it “Explora” but other makers seem to have stuck with the paradox name.

And this is definitely one for the “how weird does it get” file — a smoothbore SKS that is one short hop removed from the Webley-Fosbery Automatic Revolver!

G36: A Debacle, in a Fiasco, Wrapped in a Clusterbleep

The G36 saga keeps spreading its Sturm und Drang around the fraught world of German politics.

Our good friend Nathaniel at the Firearm Blog flagged us to a Deutsche Welle report that reminded us that there have been a lot more developments in this Neverending Story. BLUF: none of those developments suggest a rapid fix for the real problem with the rifle, no more do they suggest a way to restore lost soldier confidence in the rifle, and instead they show a military-technical problem becoming a political football. And the game is world, not North American, football, which ensures it will get kicked around a lot before it gets in the goal — if it ever gets in the goal.

Here’s video from the fight that started the whole controversy:

There are several different firefights represented in that video. But near the end of the video, the narrator mentions that the men of “Golf” platoon have been in a running firefight for 9 hours. And then, as they are withdrawing under pressure, a vehicle is struck by an IED. And “several rifles fail due to overheating.”

For all that, we don’t have audio of a lot of rifles firing on full-auto. Instead, we hear single shots and occasional short, controlled, bursts, and the longer, extremely fast bursts of the high-cyclic-rate MG3 (improved MG42). We hear enough to know that these men from the 313th Parachute Infantry Battalion are stone pros. But that’s where the problems began, back in 2010: the troops began to notice that their rifles were underperforming.

Tests, which leaders probably expected to put the modern Landsers’ complaints to rest, began to bear the troop complaints out. If the barrel was heated cherry-red, accuracy declined. Two magazines on rapid semiauto fire? Accuracy declined. If the outside air temperature was more than 23ºC at sea level (about 77ºF), not very high at all, accuracy declined. HK responds: “Hey, that wasn’t the standard we had to meet with the gun, that wasn’t the original test.” True enough, as far as it goes, but that doesn’t make the rifle combat-worthy. How much does accuracy decline? Here’s a handy graphic from Reuters via DW. At 600m, at 30º, instead of hitting an enemy in the window of a building, you might hit the building:

G36 temperature-related failure

Even at 200m, your dispersion is looking like a meter in diameter. (30ºC is about 90ºF, quite a high temperature for Europe).

The German magazine Der Spiegel (“Mirror”) has been all over this. This link should search Spiegel for “G36″ (results in German, selbstverständlich).  Here are some of the results:

At First, it Was About the Gun…

18 April 15: H&K Defends the Breakdown Rifle (which only partially gets the degree to which the neologism Pannengewehr is a putdown of the company and the firearm). HK’s majority owner Andreas Heeschen told a newspaper “Anything we make is 100% combat-ready.” On the same day (different story), Spiegel reported that H&K itself conducts the official proof tests and applies the official marks itself (which is probably not the departure from the norm that the magazine’s writers think). The responsible agency, the Bundesamt für Wehrtechnik und Beschaffung (BWB), had delegated this authority to H&K based on past performance. Again, on the same date, the MOD reiterated that the rifle was only provisionally suited for use (another Spiegel story, same date), and that it “endangered the lives of German soldiers.”

Apart from HK’s bluster and threats of lawsuits, the only positive G36 story appearing in Spiegel came the next day, suggesting that the Kurds liked it, at least. And Lithuania and Latvia appear to be satisfied with their G36 purchases.

“With us there has been no trace of technical problems with the G36. On the contrary: the weapon is super”, Pesh Merga Minister Mustafa Sajid Kadir said. “It works without problems. We’d gladly have more of them.” Last year the Bundeswehr gave the Kurds, along with other weapons, 8000 G36 rifles for their fight against the “Islamic State” terrorist militia.

According to the Latvian Defense Ministry, the model used their is “significantly” different from the German variant. A spokeswoman said that there had been no problems in quite a long time..

Also, in neighboring Lithuania the affair in Germany is not in the news. The military command are “aware that there other nations have been confronted with problems with the accuracy and the robustness of certain parts of the G3, said Major General Jonas Vytautas Zukas, commander of the Lithuanian Army. But there is no thought of backing off from the rifle for that reason. Much more there are plans to order additional G36s. “These weapons meet the requirements of the Lithuanian Army.”

The Defense Minister moved decisively on 22 April when she said that the G36, as currently configured, had “no future in the Bundeswehr.

But Soon, it was About the Cover-Up

As it became clearer that the initial heads-up about G36 problems came from a series of firefights by German paras based in the Provincial Reconstruction Team in Mazar-e Sharif in north central Afghanistan in 2010, and the technical verdict on the problem was largely in during 2012, the political fallout began to raise a noise level that drowned out the voices calling for a technical fix.

Spiegel found that in 2010 and 2011, the German Special Forces Command KommandoSpezialKräfte (KSK) were already looking for a G36 replacement that would be accurate to 300m and capable of selective fire. They didn’t call it a G36 replacement, instead terming it a “close range sharpshooter rifle,” but the weapons tested tell the story: HK 416, SIG 516, Schmeisser Solid and one unnamed competitor. It was a small contract: 5,000 rifles. Spiegel writes, “Insiders suspect that the competition concealed a Ministry of Defense search for a G36 replacement.” But Spiegel can’t have it both ways: was the MOD clueless, or was it scheming? It’s illogical to suggest it was both, which the magazine at least has the decency to avoid by putting the two speculations in different stories.

Various politicians in Germany were calling for the head of Thomas de la Maizière, the Defense Minister on whose watch the problem should have surfaced, but seemed to be covered up. Others pointed to the incumbent, de la Maizière’s party colleague and replacement at MOD Ursula von der Leyen, as the necessary sacrifice. Indeed, by 20 April, days before her pronouncement that the G36 had “no future,” Spiegel was contrasting her high hopes at her swearing-in to the way the chaos of the G36 affair threatened her political career, perhaps not by getting her fired now, but by blocking any further advancement for the ambitious politician.

Competing leaks have pinned responsibility for the cover-up on de la Maizière and on von der Leyen. They describe the accuracy problem various ways: “twice as bad, three times as bad” or, chillingly, noting that with the issue firearm and ammunition combination, “a hit at combat range is not possible.”  One German politician spoke up as the voice of fiscal sobriety:

In almost every armaments scandal we see the same picture: bad material was bought expensively, no one is responsible in the end, and the taxpayers have to pay.

The finance hawk? Jan van Aken of Die Linke, the rump vestige of East Germany’s communist Quislings. Van Aken is a member of the legislature’s Defense Committee.

The most recent, and damaging, release is that a former MOD official sicced a military intelligence agency on the leakers and the reporters they leak to. The Militärabschirmdienst (MAD), or Military Protective Service, is a counterintelligence agency of the Bundeswehr. The MAD appears to have drafted a plan to defend the G36, the Ministry, and HK by going on clandestine propaganda offensive against press critics. The plan was never approved, and the head of MAD transferred laterally to another job, but the scent of the problem has drawn more opposition sharks.

None of this inside-Berlin political drama has any prospect of restoring either German soldiers’ confidence in their individual weapon, or equipping them with an individual weapon in which they can have confidence. But von der Leyen will have to take measures in that direction soon. Or she will have a successor who will.

At least the Germans have alternatives. India recently gave up on the equally problematical (in different ways) home-grown INSAS rifle, and really had nothing to offer its frontline troops but old AK-47s.

Lee Williams: Down With Poly AK Mags!

Lee Williams has had it with polymer AK mags, and this is his reason:

The mag blew up while sitting unattended in Lee’s safe, and the resulting chaos was waiting for him when he opened it up.

I’m done with polymer AK mags
Posted on April 30, 2015 by Lee Williams

I had a surprise last night when I opened my safe.

The top of a loaded polymer AK mag had broken off for reasons unknown, spraying 28 loaded rounds and bits of plastic all over my safe.

The spring was sticking halfway out of the top of the mag. I found the follower behind an SKS.

via I’m done with polymer AK mags – The Gun Writer.

We agree that this is an unhappy thing. We don’t agree that all polymer mags are created equal. (Ask any Glock owner who’s tried both Glock mags and the temptingly cheap Korean knock-offs). Even all polymer AK mags.

The Russians were the first to issue a synthetic magazine widely, and in the 1970s began producing polymer magazines with reinforcements in critical areas for the AKM and AK-74 rifles. These are the characteristic orange mags. They’re a good bit heavier than modern polymer mags, a lot heavier than US or Western-style aluminum or even steel mags, but are a lot heavier than thick-sheet Russian AK mags. Ivan’s polymer/steel composite-construction mags are about as durable as the steel mags they replaced (and significantly lighter). Collectors call these “Bakelite” mags, but the material does not appear to be Bakelite at all — it’s some other form of thermosetting; a Finnish article reprinted on a US site, minus most of its original photos unfortunately, says that it’s “fiber-reinforced phenol.” (We wonder if that’s a mistranslation that should have been phenolic instead).

To our disappointment, an unclas tech intel bulletin on the mags that we know was out there, was not available on DTIC. There is an interesting page on the net that lays out various mags for 5.45mm-class weapons, and some of that transfers to the 7.62mm versions. Anyway, we haven’t brought one of these mags to our injection-molding expert friend, but the original kind of feels like urea plastic to us. The Circle-10s are something lighter, maybe even ABS (ordinary polystyrene, like in hard-plastic toys).

The mag that disassembled itself on Lee was indeed a Bulgarian “Circle-10″ mag, a marking associated with Arsenal, and as you can see, it is by design not reinforced, neither with steel lips nor fiber reinforcement.

What makes a mag fail like this? Lee seems to think that the guilty party is leaving the mag loaded for a length of time. We have our doubts about that and would be more inclined to suspect the cumulative effects of age and ultraviolet-ray exposure (plain ordinary sunlight, which it certainly couldn’t have gotten in his safe). But the durability of different AK mags, even different Bulgarian mags, is widely variable.

We also don’t think loading only 28 rounds buys you anything. The difference in pressure is nominal. This goes back at least as far as Vietnam and was a ritual practiced by troops (although, there it was putting 18 rounds in a 20-round magazine) who were neither trained on the rifle nor given a supply of replacement magazines. It was something they did to appease the M16 Gods

The plain ugly fact is that magazines are, by design, expendable items and you need to start thinking of them that way — they’re the toilet-paper of small arms, necessary but not especially durable or reusable. And just like toilet paper, some brands are better than others. Lee, for example, probably should dump all of his circle-10s that are the same age as the one that failed, because their clock is ticking, too. Sorry to be The Bear of Bad News.

In the real world, private owners and armies alike are reluctant to purge their bad magazines because the mags represent a considerable cost — both the sunk cost that was spent on them and is lost for good, and (more germanely) the replacement cost for new mags. It is possible (although not necessarily economical or practical) to repair or overhaul metal, especially steel, magazines, but synthetic materials are harder to repair and rebuild.

Twist Rate Affects Ballistic Coefficient

Bryan Litz with, once again, some science that makes our hair hurt, and that’s even in his cut-down version with minimal traumatic math. In a post excerpted from his latest book, Modern Advancements in Long Range Shooting, Litz discusses the results of tests with a rifle and a series of barrels manufactured by the same barrelsmith to differ only in twist rate, and be identical in all other aspects — a controlled experiment.

The Litz Lab -- a precision rifle with a set of barrels differing by only a single variable.

The Litz Lab — a precision rifle with a set of barrels differing by only a single variable.

Through our testing, we’ve learned that adequate spin-stabilization is important to achieving the best BC (and lowest drag). In other words, if you don’t spin your bullets fast enough (with sufficient twist rate), the BC of your bullets may be less than optimal. That means, in practical terms, that your bullets drop more quickly and deflect more in the wind (other factors being equal). Spin your bullets faster, and you can optimize your BC for best performance.

Any test that’s designed to study BC effects has to be carefully controlled in the sense that the variables are isolated. To this end, barrels were ordered from a single barrel smith, chambered and headspaced to the same rifle, with the only difference being the twist rate of the barrels. In this test, 3 pairs of barrels were used. In .224 caliber, 1:9” and 1:7” twist. In .243 caliber it was 1:10” and 1:8”, and in .30 caliber it was 1:12” and 1:10”. Other than the twist rates, each pair of barrels was identical in length, contour, and had similar round counts.

There’s quite a lot to get your skull around here, and even when you Read The Whole Thing™ (which you’re totally gonna do, right?) there’s stuff that’s hard to understand.

It led to quite a lot of barrels to keep organized!

It led to quite a lot of barrels to keep organized!

We wonder what the mechanism is that, in effect, raises the drag (and BC) of an underspun bullet, and what we think it is is a form of precession. Instead of spinning perfectly around its longitudinal axis, the bullet wobbles a little bit off axis. Instead of going along a perfect line, and therefore staying in a single point, as viewed in 2D from dead ahead, the point of the bullet is describing, when reduced to two dimensions, a small circle… in three dimensions, the point is spiraling towards the target even as the bullet’s center of mass is proceeding directly targetwards. There are several ways that this could raise the drag of a typically supersonic bullet. One is simply that the off-axis bullet may present a larger frontal area (or larger average frontal area, if the precessing bullet has a changing frontal area) to the slipstream. Another is that flow might separate irregularly from the tail of the bullet. Turbulent, separated flow induces buckets of drag. There are probably others that we don’t get because, unlike Bryan Litz, we’re not aerodynamicists by training.

Linearity of the results is striking.

Linearity of the results is striking. A 0.87 correlation quotient is an extremely solid result. 

One thing that Litz points out is that you may be getting very satisfactory groups, and still not optimum BC. Why does that matter? If your groups are OK and your BC is suboptimum, who cares? Well, BC (as Litz shows, practically a function of gyroscopic stability) also influences accurate range, for example.

It’s a common assumption that if a shooter is seeing great groups and round holes, that he’s seeing the full potential BC of the bullets. These tests did not support that assumption. It’s quite common to shoot very tight groups and have round bullet holes while your BC is compromised by as much as 10% or more. This is probably the most practical and important take-away from this test.

Like all of Litz’s research, this is some fascinating stuff. The same series of tests also showed that twist rate affects muzzle velocity, but very little. It’s intuitive that a higher twist rate would, by imparting more friction to the projectile, decrease muzzle velocity. The results, though, showed that while twist rate affects MV a statistically significant amount, that amount is extremely low. As Litz puts it, himself, in a couple of  the comments to the post:

The scatter in the data and the R squared value indicate that only about 1/2 the variation in MV is due to twist rate (Correlation Coefficient is 0.55) which means that random noise has as much effect as twist rate. This is discussed further in the book, as well as similar results presented for a different bullet in which the relationship was even weaker, and the correlation was lower.

Remember that the correlation quotient between twist rate and BC was 0.87. Random chance probability is 0.50, so unlike the twist-to-BC correlation, the twist-to-MV correlation is weak as water… but it’s still there. It’s a measure of Bryan Litz’s painstaking care in collecting this data that the 0.55 correlation even shows up in the data table, but it does, as a low double-digit variation in MV with each change in twist rate!

Linear, but barely perceptible, results. Amazing.

Linear, but barely perceptible, results. Amazing. As Litz notes, the experimental variation is smaller than the SD of the individual data points — if the relationship weren’t completely linear it would probably be invisible. It only shows up on the chart because of the suppressed zero value on the scale. 

The point in presenting these results is to show that the effect of twist rate on MV is VERY minor, and can almost be said to be statistically “in the noise”. ….

The long and short of it is that regardless of caliber and bullet weight, twist rate has very little effect on MV. You’ll see more fps difference per inch of twist on a .220 Swift just because you’re dealing with higher velocities. In other words, the percentage of MV change due to twist is pretty consistent.

That’s an example of how the comments are as good as a second, followup post in terms of their educational value. If you had asked us, we’d have said that, so long as the bullet was stabilized at some minimum level, twist rate would have had a minimal effect on accuracy, but a larger one on MV. And yet Bryan Litz’s results are exactly the opposite of what we’d have said on instinct. Obviously we didn’t understand this as well as we thought!

So read the post and comments — and keep reading till you understand it all, which may take those of us who are reformed infantrymen more than one reading. And if you want a deeper dive in the physics of accuracy, Modern Advancements in Long Range Shooting, and Litz’s other books are available from Applied Ballistics directly or from Amazom.com (at a glance, it looks like you save money by going to Applied Ballistics).

What’s After Tracking Point?

We’ve been pretty high on precision guided weapons technology since the first time we saw a TOW do its thing. (And Javelin and other current weapons have answered most of the complaints about TOW since then). But in recent years, the promise of PGWs has migrated down into the small arms world, thanks to the same combination of Moore’s Law, free-flying science and nitty-gritty engineering that gives us everything from rapid genome sequencing to haptics and 3D printing.

We’ve been pretty impressed with the precision-guided rifles and Tag / Track / XACT technology of Tracking Point. So what comes after that? DARPA says: precision-guided, steerable bullets. They call the program, in a felicitous acronym, EXACTO, Extreme Accuracy Tasked Ordnance. Like the Javelin and the Tracking Point PGW, it seems to tag a target and then pursue it relentlessly.

DARPA recently released the above video, along with this blurb:

DARPA’s Extreme Accuracy Tasked Ordnance (EXACTO) program, which developed a self-steering bullet to increase hit rates for difficult, long-distance shots, completed in February its most successful round of live-fire tests to date. An experienced shooter using the technology demonstration system repeatedly hit moving and evading targets. Additionally, a novice shooter using the system for the first time hit a moving target.

This is not too different from what TrackingPoint does now, in terms of results. What is different is how the EXACTO round functions.

This video shows EXACTO rounds maneuvering in flight to hit targets that are moving and accelerating. EXACTO’s specially designed ammunition and real-time optical guidance system help track and direct projectiles to their targets by compensating for weather, wind, target movement and other factors that can impede successful hits.

You can see from the video that they’re getting hits on their e-type silhouette, but they don’t appear to be getting center of mass hits. Still, it’s an admirable case of the dog walking on his hind legs, and this suggests that the science is licked, and what remains from here on out is simply engineering. (Not trivial, engineering, but once the science has shown that something is possible, it’s up to the engineers to find elegant and practical ways of doing it).

One significant difference between this and Tracking Point’s technology (so far) is that TP uses a bespoke or customized weapon; according to DARPA, EXACTO works with an ordinary rifle, only the optoelectronics and ammunition are changed.

It’s not rifle-caliber, as usually designated, yet; this demo is with a .50 caliber smart projectile.

“True to DARPA’s mission, EXACTO has demonstrated what was once thought impossible: the continuous guidance of a small-caliber bullet to target,” said Jerome Dunn, DARPA program manager. “This live-fire demonstration from a standard rifle showed that EXACTO is able to hit moving and evading targets with extreme accuracy at sniper ranges unachievable with traditional rounds. Fitting EXACTO’s guidance capabilities into a small .50-caliber size is a major breakthrough and opens the door to what could be possible in future guided projectiles across all calibers.”

The EXACTO program developed new approaches and advanced capabilities to improve the range and accuracy of sniper systems beyond the current state of the art. The program sought to improve sniper effectiveness and enhance troop safety by allowing greater shooter standoff range and reduction in target engagement timelines. For more information, please visit the program page.

via 2015/04/27 EXACTO Guided Bullet Demonstrates Repeatable Performance against Moving Targets.

OK, so let’s visit the program page, shall we?

Turns out, there’s not all that much there. We do get an uninformative 3D rendering of an EXACTO projectile, but that’s about it. There is a suggestion that the steering of the bullet is aerodynamic in principle.

exacto projectile_fullThere is this brief update on where the project stands:

The EXACTO 50- caliber round and optical sighting technology was developed to greatly extend the day and nighttime range over current state-of-the-art sniper systems. The system combined a maneuverable bullet and a real-time guidance system to track and deliver the projectile to the target, allowing the bullet to change path during flight to compensate for any unexpected factors that may drive it off course.

Technology development in Phase II included the design, integration and demonstration of aero-actuation controls, power sources, optical guidance systems, and sensors. The program concluded with a system-level live-fire test.

In 2009, the project was described as follows [.pdf]:

Extreme Accuracy Tasked Ordnance (EXACTO)* *Formerly Laser Guided Bullet.

(U) The Extreme Accuracy Tasked Ordnance (EXACTO) program is developing a system that provides sniper teams with the ability to identify and engage targets with heretofore unobtainable range and accuracy against stationary and moving targets under difficult environmental conditions, either day or night. The system uses a combination of a maneuverable bullet and a real-time guidance system to track the target and deliver the projectile to target. Technology development includes the design and integration of aero-actuation controls, power sources, and sensors. The components must fit into the limited volume (2cm to the third power) of a 50-caliber projectile and be designed to withstand a high acceleration environment. When integrated and tested, this system will greatly increase the effectiveness of two-man sniper teams, regardless of the environmental conditions and the time of day. The EXACTO technology is planned for transition to the Army by FY 2012.

FY 2009 Plans:

– Design guidance system.
– Design maneuverable projectile.
– Construct all novel 1x scale components.
– Measure component and subsystem performance in appropriate environments.

An Air University paper said this of EXACTO, comparing it to aviation precision guided munitions programs:

Foot soldiers are often left out of consideration when money is spent on precision weapons. The DARPA Extreme Accuracy Tasked Ordnance (EXACTO) is a command-guided .50 Cal sniper round designed to put long range, pinpoint precision in the hands of a common soldier. The system works by tracking a target with an infrared spotter’s scope that doubles as a command- guidance tracker. The .50 Cal bullet is fired and responds to trajectory commands sent by the scope (which tracks the target and bullet). The system accounts for wind, moving targets, and provides accuracy at range that normally requires years of sniper training to achieve. The EXACTO program not only gives sniper capabilities to common foot soldiers, it ensures a kill on the first shot, and enables moving target capabilities that have until now only been available to tactical aircraft and UAVs. In this case, the range is far shorter than HTV-21 or T32, but the strategic implications of super-sniper-battalions may prove even more deterring to an enemy force. For years, the real practical advantage US soldiers held over adversary soldiers came in the form of the air power watching over. EXACTO aims to enable America’s soldiers to enjoy technological advantages its airmen have enjoyed for decades.3

Although EXACTO was indeed scheduled to conclude in 2012 [.pdf], and some DARPA pages refer to it in the past tense, but the live fire test video shown here was shot in 2015 and only released in April (in-house, 10 Apr 15, to the public, 27 Apr 15).

Notes

  1. HTV-2: Hypersonic Test Vehicle-2.
  2. T3: Triple Target Terminator-3, an experimental missile that combined a ramjet sustainer with a rocket booster in the form factor of a pre-existing missile.
  3. Nielsen, Michael B. (Maj., USAF). Addressing Future Technology Challenges through Innovation and Investment . March, 2012: Air University, Maxwell AFB, Alabama.

Part-Original Colt Armalite Model 601 on GunBroker

A very rare M16 variant, fully transferable, is up for auction on GunBroker. It’s the retro AR guy’s Holy Grail — an original Colt Model 601. It has a low serial number (605), meaning it was one of the first production ARs, making it a gun of notable historical significance. It’s being offered by a reputable seller (Frank Goepfert/Midwest Tactical).

That’s the good news. The bad news? It’s going to be very expensive. They’ve set a buy-it-now of $35K, and the no-reserve auction is already bid up to over $19,000 as we draft this (we suspect it will be higher yet; ordinary M16A1s bid up to this level all the time). And the ugly news? While the gun is described as original in the auction writeup, which we excerpt below, it’s not. Not even close. After the blurb, we’ll tell you what’s missing, and what’s “off” about this rifle.

Colt Armalite model 601. These were the gun that started it all. They are considered the first production M16. These primarily went to military buyers but a few were sold to LE, some of which made it into civilian hands. The 601 is the only M16 on the C and R list! The “01” would be one of my personal top picks for an NFA investment due to the limited number available, the Colt name and the fact that they are a C and R gun. The gun you are bidding on is in nice condition. We have it here on hand. The bore is good, all parts are original and the gun works perfect. The caliber for this firearm is .223. According to the ATF paperwork, Colt Ind. is the maker for this firearm. This will transfer direct to your c3 dealer tax free from our inventory on a Form 3 without delay after payment is made. This is the fastest type of transfer so approval and shipment to your ffl should not take long.

via M16 Colt Armalite Model 601 C and R : Machine Guns at GunBroker.com.

Note how the mag-well bosses in the lower receiver match the upper receiver exactly.  That is a 601 characteristic; by the 603 model (with the forward assist, the one that went to the Army for general issue in Vietnam) these did not align perfectly any more.

While this rifle clearly contains some rare and hard-to-find 601 parts, like the dimpled pins, straight ribbed magazine release and bolt release, and slightly-differently-cut 601 upper and lower receivers, it’s also got a lot of later-AR pollution on it.

The characteristic green-then-black- oversprayed brown mottled fiberglass 601 furniture appears to have been replaced with more durable, but dirt-common, M16A1 furniture.

The early-601 barrel has been replaced by a not-quite-as-rare and distinctly different 1967-vintage chrome-chamber-only M16A1 barrel, a so-called MP-C barrel, and the early barrel, FSB and flash suppressor are not included with this firearm.

This is the C that marks chrome chamber, quite rare in its own right but not correct for a 601:

The bolt carrier group has been replaced by a common M16 or AR BCG.

It’s also been refinished a later, darker shade of anodizing.

Whoever buys this will have to spend thousands (and probably take years, waiting for parts to come on the market, or for repros to be manufactured) to really own a 601 — and even then it will be a restored firearm, not an original. For example, the last set of 601 handguards we saw in really nice shape was five or six years ago, and the guy wanted $1,500 for them.

So how to appraise this semi-601? Its mixmaster status means that it’ll never have the appeal to auction with Rock Island, James D. Julia, or even Poulin unless that long and costly resto is done, and even then, some of the deepest-pocketed collectors will shy away from it (unless it’s described inaccurately or dishonestly… but now the Intertubes know that this firearm, SN 000605, was a mixmaster as of April 2015, and the Internet never forgets).

The bottom line? It is what it always is.

Caveat emptor.

SIG MPX QC Trouble? Or One Guy Got One Lemon?

We are big fans, in theory, of the SIG MPX. We’ve been following the saga of the gun itself, and of the company’s battle (a losing battle, so far) to get their innovative muzzle-brake-converts-to-suppressor-with-a-registered-tube version approved by ATF. We like the look of this modernized take on the MP5 form factor, and now people are starting to get them out in the field. And that, as Art Spiegelman wrote of his dad’s experiences, is where the troubles began.

Several versions of the MPX are shipping -- but this one looks dead for the forseeable future.

Several versions of the MPX are shipping — but this one looks dead for the foreseeable future.

Bearing Arms had a report on a problem with a production MPX. The problem was experienced by a guy named Darrell with a YouTube channel he calls “Tactical Existence” (really?); his tagline (gagline?) is: “Tactical is not just a word it’s mindset & a lifestyle.” (Punctuation his).

You don’t say.

Anyway, the guy’s website has the MPX video at the top. However, he does not show the MPX malfunctioning out of concern for his own liberty.Initially, he loved the MPX, firing it with the SIG Brace against his cheek and fastened to his arm. But then it began to double on him. His explanation:

We started with a fresh case of PMC 9mm brass ammo, and much to our surprise the gun almost immediately started to have serious malfunctions. At first we weren’t sure if the guns having some weird sort of bumpfire situation, or if it was something more serious like a double fire. After running a few quick test there was no doubt that the gun was in fact having a double fire malfunction. The weapon would fire with a pull of the trigger and then again on the reset of the trigger. this is a big problem because as most of you already know if you are in possession of a firearm that fires more then one round with a single pull of the trigger it’s your fault no matter if it is or not, well in the eyes of the ATF anyway.

That’s a reference to US v. Olofson, right there, although he might not know the name of the case he understands its legal import. And that’s why his video isn’t embedded here — since it doesn’t show the failures, it’s not really of interest to us, but we understand why he didn’t want to put incriminating evidence, at least as the ATF sees it, on the web.

The cause of the double-fire was a bit unusual:

After figuring out that we had an issue I took the lower receiver off the gun to inspect the trigger group. I found that the trigger group pins had walked out of the gun and was causing the hammer not to catch the disconnector. We then put the pin back in the gun and test fired to see if this fixed the problem, which it did for a second anyway. After about 20-25 rounds both trigger group pins were starting to walk out of the receiver again, at this point we stopped shooting the gun and called Sig for repair.

We’re not really sure how you fail to notice the pins walking out of the gun in the first place. The original AR-15 trigger module design used the springs themselves, riding in grooves in the pins, to retain the pins and was very effective at doing that. People who’ve had pins walk have usually had grooveless pins, the el cheapo kind.

Here is a video showing the trigger mechanism of another guy’s MPX at about 3:22 to about 3:50. At 3:36 you can see two pins, one of which has faint grooves and one, no grooves at all, in the upper left quadrant of the video. (We’ve cued it up to start at 3:02. You can wind it back if you want the whole thing).

This guy had the trigger mechanism out to replace the trigger spring with a lighter one, to reduce the trigger pull.

The MPX enters a crowded market for 9mm carbines and submachine guns. (The gun’s original design concept was a product-improved MP5). It’s not the market’s incumbent entry (that position is held in the LE market by the MP5, still marketed in a desultory way by HKUSA, and in the civilian market by 9mm AR clones), and it’s not the low cost entry (that would be the CZ Skorpion Evo, less than half of what scalpers are getting for MPXes right now, and with mags perhaps 1/4 of the SIG’s Lancer polymer mags). So it’s vital for SIG to get this right.

The modular rifle-caliber suppressor-host SIG MCX, which shares some components and concepts with the pistol-caliber MPX, has also had, in some examples, feeding problems. This suggests SIG still struggles with QC, but seems completely unrelated to the walking pins in this one example of the MPX.

The fanboys at SIGForum.com have been watching this for some time. This link picks up the MPX thread on p.24 in March and you can continue forward from there, including a discussion of the Tactical Existence report. Several forum members have fired more rounds that Darrell managed to do, and none have had walking pins. A more common problem cited by the forum members is a complete lack of spare mags, so far.

Notes

  1. Darrell is thinking, no doubt, of US v. Olofson, where a guy was convicted for a gun that ATF SSA Jody Keeku and the amateur gunsmiths of Firearms Technology Branch spent four months massaging; they bubba’d it until it doubled 50% of the time. David Olofson spent several years behind bars (he’s been out for years now, but he’s a felon forever). Showing the MPX doubling would be giving the ATF all the evidence they need to throw Darrell in prison on the Olofson precedent, not that they really pay any attention to precedents.

 

 

Form 4: REJECTED.

Got that letter from the examiner. (Actually, our FFL got it some days before we did). BORK. So what’s the problem?

This is a file (factory) photo of the gun in question.

This is a file (factory) photo of the gun in question. Ours is used and was a good buy… although we’re coming up on a year without putting our mitts on it, yet.

Turns out a paperwork glitch on our end. The CLEO signature was fine, but no one put the CLEO title in the title block.

So back it goes to ATF.

The purchase (an M1 Thompson SBR by Kahr) was done in July, 2014, but we didn’t get our form to the ATF until November (that’s not ATF’s fault, but ours). So it took, from the time they’ve had the form, a hair over five months for this technical rejection. We’ll put the Chief’s title on it (they did send details on what was wrong with the Form 4 and how to fix it) and send it back, and then it goes back to the same examiner rather than wait another five months in the queue. Which is nice.

We may have the Thompson at the range one year after buying it.

Well, largely our fault for missing such an obvious detail.

How long is it taking for ATF to process these forms?

We’re going to give you an answer you’ll hate: it depends. There may be some elements of go-slow in the Administration’s approach to ATF doing its duties — certainly many of the senior personnel in ATF are anti-gun and politically partisan — but it really seems to be explained well enough by ATF’s finite number of examiners getting slammed by an explosion in quantity of NFA submissions. Here are the last two years, thanks to NFA Tracker.com (it does embiggen):

NFA Stamp Wait TimesOne of the interesting results here is the general downward trend in wait time, both for trust submissions and for paper submissions. A few outlying trust e-File submissions have gotten same-day service, and Form 4 trust submission review times have suddenly trended up in 2015. (ATF does report they’ve had some problems with badly formed trusts that were set up without a specialized attorney).

The trendlines get even more interesting if you go back to the full dataset on NFA Tracker, which takes us back to 2006, before the advent of the World’s Greatest Gun Salesman.

longterm_wait_times

Again, it embiggens if you click it. As you can see here, prior to 2009 transfers seemed to be a 30-60-90-day thing, although the data is pretty thin at that point. In January 2011, approval times started to increase rapidly until by the fall of that year, and for the next 12 months, approval times clustered close together, centered on a median of about 180 days or six months.

Then, after the 2012 elections, the delays skyrocketed again. peaking at nearly a year in the summer of 2013, and then descending.

It’s also significant, we think, that all kinds of forms and filing methods seem to have been treated similarly until around September 2013, when some (principally, e-Filed forms) began to show much more rapid adjudication than paper forms of similar type.

This data pattern looks to us more like an agency struggling to serve more customers than it has ever had to handle before, than the fruits of any kind of conspiracy.

We could simplify life for the NFA Branch and its examiners by changing the law so that SBRs, SBSes, and suppressors are handled as Title I firearms. Handling these within the strictures of the NFA does not prevent or solve crimes, after all; these weapons are little used in criminal activity, and the ones that are so used, are almost always stolen. Therefore removing these low-crimefighting-value firearms registrations from the pool would reduce the workload on the examiners and let them focus on efforts more useful to actual crimefighting.

Some Thoughts on Police Trade-Ins

Favorite FFL emailed his list of customers to say that he had some police trade-ins:

Available starting tomorrow at 9AM are these police department trade in guns.

Bushmaster XM15E2S 5.56mm rifles.  16″ barrel, collapsible stocks, will come with one 30rd mag.  Used, cosmetic blemishes from being in cruiser racks however mechanically sound.  We also have a special going with our Cerakote vendor to get $25 off a refinish with Cerakote gun coating if you so desire.  $475

File photo of a Remington 870 tactical police shotgun

File photo of a Remington 870 tactical police shotgun

Remington 870 Police Magnum 12ga pump shotguns. These have 18.5″ standard barrels with sights.  Two have BlackHawk recoil reducing stocks and two have regular stocks with side saddle shell holders. These also will have some finish wear as well but are mechanically sound.  $325

They’re going to be gone by now, probably; he just had single-digits of each.

Meanwhile, SF Buddy on the phone described his new score:

An HK imported Benelli shotgun that the local detectoves used to use. They have changed (not upgraded) to Mossberg pumps.

Aside: asks your humble host: “Wha’s wrong with a Mossberg pump?”

Turns out, lots of things, but basically, the single aluminum alloy op-rod is prone to bending when used hard. When Army Mossbergs had this problem, the answer was, per Mossberg, a thicker aluminum op-rod… result? One thicker bent aluminum op-rod.

He’s very pleased with the new gun so far. It was a lot more expensive than the above-referenced 870s, but it was a good buy for an HK-era Benelli.

Pros and Cons of Police Trade-ins

Police trade in weapons when they buy new ones, in most states and cities. This lets them save a lot of money on this vital equipment, while keeping their equipment pool up to date (and sometimes, even, under warranty).

The strengths of these weapons usually are:

  1. The weapon design and manufacture was generally good. Police agencies seldom buy junk. When they trade them, it’s more likely to be because they are out of fashion than any real substantive difference between the new guns and the old.
  2. Police weapons are usually chambered for what is thought at the time to be an effective cartridge. All 20th and 21st-Century police firearms can be effective on homo sapiens, to the extent that a handgun can be, with well-selected or handloaded rounds.
  3. The weapons are usually little shot and in good mechanical shape. 90% or more of cops would sooner attend a Free Mumia rally that shoot a single round more than minimum to qualify, so few of these weapons are shot out.
  4. The weapon was subject to some kind of periodic maintenance and inspection.
  5. The police provenance may give you an entertaining story to go with the gun. Or not.

 

PSP Patch Beretta 2

The Pennsylvania State Police is one agency that disposes their used handguns — in this case, a Beretta 96.

 

Weaknesses of these weapons usually are:

  1. Because PDs so dependably follow trends, you’re probably picking up something from one trend ago.
  2. They generally only come in limited configurations. If you prefer, say, the 9mm to the .40 S&W, you don’t get to choose, the way you would with a new gun.
  3. The weapons are usually in fair to poor cosmetic shape, and may not have been cleaned in a long time — if ever.
  4. Cop trades, unless a very large agency suddenly gluts the market or the agency’s version of the gun had market-toxic lawyer “improvements” like a New York or DAO trigger, tend to be priced a little higher than similar used guns.
  5. Police guns are bought by collectors as well as users, especially if the firearm is marked with police identification.