Category Archives: Weapons Technology

Bubba Got a Boring Bar

bubbas boring bar AR

This is weight savings the hard way, considering that most of what’s cut away is 7075 or 6061 aluminum. You just can’t save that much weight that way.

CubanFALThere are FALs kicking around Latin America and Africa with a big borehole like that in the magazine well — that’s because they were supplied clandestinely by Cuba, and los Pollos Cubanos used the boring bar (or maybe a fly cutter, we defer to the machinists in the audience) to remove the Batistiano Cuban crest in hopes of concealing the guns’ origin. (Lotsa luck. Western intel agencies had the manifests of the deliveries, by serial number).

We found the Swiss-Cheese-AR image here, linked from here, hat tip Nathan S at TFB.

Aero Precision has gotten into the game with some gimmicky skeletonized lowers. This is not a production item, but was an experiment:

Aero Precision SkeletorThat’s also thanks to TFB. Structurally, it might hold up or it might not (really, most of the material in the sides of the lower is there to provide dust seal, and, to a limited extent, a shear web, so there’s no reason skeletonizing shouldn’t work, structurally). But the total weight savings is nominal: 0.169 lb or about 2.7 ounces. (About 0.08 Kg for those of you who roll that way). They could probably have saved almost as much by milling off the A2 reinforcements to the pivot pin lugs and buffer tower areas.

That gives you an idea of what Bubba’s Boring Bar Blaster actually saved: less than 2.7 oz, to be sure. That’s winning the game the hard way.

Aero Precision is not alone. Daytona Defense & Tactical sells a skeletonized “Reaper” lower for $85 bare and $90 anodized black. It looks like they took many of the same cuts Aero Precision did (we’re not going to guess who was first).

Daytona Defense Reaper

So what’s the game? As you might guess from all the discussion of weight, The Lightest AR Going. There’s a Tumblr where a guy aimed for 60 ounces (he overshot but not by much), and there are several other competitors around. So a new guy’s aiming below 60 ounces. Of course, his definition of a “fully-functional AR” may not gibe with yours — one of the first parts he sacrificed was the bolt catch, shortly followed by the magazine catch (he’s making a fixed-mag 10-round firearm). And we’ve got our doubts about the long-term viability of his aluminum bolt carrier (yes, really). But even he has said, he’s not drilling the thing full of holes.

It might be that X Products got the whole Gun of Skeletor thing started by, after a skeletonized drum magazine caught the public’s eye at SHOT, making a run of the things. (Not a short run, either. For 2015 they made 1200 Skeletonized mags for SR-25 pattern .308s, and sold ‘em out). The silhouette of the skeletonized AR-15 drum has been used as a sort of trademark by the company ever since.

Hey, you want a light AR? Going to shoot it with irons? Get an old Colt SP1carbine. Yes, it will have some compromises: iron sights only, of the less precise (and slightly harder to adjust) A1 flavor. No rails or freefloated goodies. But it’s only 6 pounds and change. If you want to get to 4 pounds and below, you can only do it by accepting unpleasant recoil, shorter life, and compromised performance.

If that’s a good deal to you, or if you just want to experiment, have at it.

 

3D Printed Fire Control Group

We’ve seen several of the WarFairy designed 3D-printed AR lowers being put through their paces, but here’s something we weren’t expecting to achieve test-fire status so soon — the Deimos 3D-printed fire control group.

The printer used was a Rostock Max V2, a deltabot style printer. An E3D hotend was used. The material was ABS filament and was treated with acetone vapor after printing. The same printer printed the lower receiver (which had mods to accept this FCG) and the FCG itself.

The FCG design is based on general best practices, adapted for 3D printing and for ABS plastic as a material. Before it is manufactured, it is rendered, both bare:

Deimos FCG rendering no receiver

And in a rendering of the lower receiver:

Deimos FCG rendering

By “general best practices,” we mean a trigger with hook or hooks, hammer (with places for the hooks to engage) and disconnector (also with hook) of the type designed by Browning over 100 years ago for such semi-auto firearms as the Auto 5 shotgun and the Remington Model 8 rifle. This general Browning design was adapted by Garand, Kalashnikov, Stoner and many other subsequent designers. (If you examine an AK and AR closely, you’ll see their kinship in this area. Both inherited the Browning fire control, the AR via Garand and the AK via Remington Model 8). This FCG has three parts in semi-auto form: a trigger, a hammer, and a disconnector.

Deimos FCG parts w springs

By”‘adapted for 3D printing and ABS plastic” we refer to changes required by this material and means of manufacture. Each of the parts is printed on the Rostock Max before getting its acetone vapor bath. And each part has some base and support material that must be removed.

Deimos FCG disconnector as printed

ABS is a strong plastic, but a brittle one. Nylon may be better; an FCG printed in white nylon (presumably Taulman 618) is shown here. It’s unknown why this version has not been given the test-fire treatment, yet; perhaps there are yet undisclosed problems with it. But the nylon works better “on paper.”

Deimos FCG nylon

Here’s the FCG in the lower, cocked:

Deimos FCG in place

And here it is, decocked:

Deimos FCG in place hammer down

The “wet look” of the plastic is a result of the acetone-vapor bath.

Home manufacturing is just getting started, and right now, it’s still for tinkerers and fiddlers, not for end users. It’s a bit like computers were in the early years — it’s in the hands of a shadowy priesthood, guardians of abstruse knowledge. But it turns out the priests are very friendly and helpful once you show a sincere interest.

It’s still harder than (and easier to go wrong with), say, starting up a new Mac or assembling an Ikea table. But so were earlier versions of the same products.

Some people will try to stop this. Lotsa luck. You can’t stop the signal.

This isn’t just about one single design for an AR fire control group. It’s about putting the tools of design, testing, and iteration — the whole RDT&E cycle, really — into the hands of anyone who’s got the nerve to pick them up.

John Browning had to file metal into shape, largely by hand, to transfer his ideas into real prototype firearms. But that was a century ago. Today, we don’t have to any more.

Latest Printed AR Lower Test Fire

This is a more recent AR lower design, called the Alimanu Phobos. Here’s an image of it:

alimanu_phobos_printed_lower

And here’s the source of that image, a video showing the lower and showing it being test-fired.

Here’s what the video post says:

A test-fire video of the Aliamanu-Phobos AR-15 Lower Receiver designed and printed by ArmaDelite. Printed with ABS plastic on a XYZPrinting da Vinci 1.0 printer, this design is derived from previous designs like the FOSSCAD Phobos, Vanguard and vanguard JT lower receivers. MOAR test fire videos coming soon!

We suspect that the feeding problems may be due to the reduced rigidity of the lower compared to a standard 7075 machined forging. If the positioning of the magazine with reference to the bolt carrier is not consistent, you might get results like this.

The files can be found here:

https://www.sendspace.com/file/lkw9nm

Don’t click any of the big Download buttons. This is what the actual link will look like.

Screenshot 2015-02-22 01.12.36

Annoy a totalitarian. Share gun design files.

 

Additive Manufacturing in Defense and Aerospace

Today, we have two links for you that will expand your knowledge of what the DOD and Aerospace world is doing with additive manufacturing.

Additive Manufacturing for Armaments

Screenshot 2015-02-19 22.56.11The first is slightly dated, because it comes from the NDIA’s 2013 Armament conference. (Yes, 2013 was a long time ago in this rapidly developing field). It is the presentation slides of Stratasys’s John Dobstetter. Stratasys (SSYS) is one of the two large publicly traded firms in the field (the other is 3D Systems, whose ticker symbol fits: DDD).

Personally, we wouldn’t cross the street to whiz on Stratasys if they were on fire, because the company is firmly antigun and pro-gun-control, but Dobstetter’s presentation is an excellent one that starts out assuming that (1) his audience knows nothing about additive, but (2) it’s a bunch of smart people who know manufacturing and catch on quickly.

Screenshot 2015-02-19 22.56.28There’s fascinating stuff about when to use additive (see the Sweet Spot slide above) and how it can be applied to every phase or stage of manufacture (see the Lifecycle Applications slide to the right). Switched-on manufacturers, like Czech airplane manufacture Evektor, are using additive parts both as tooling and as end use parts.

There are some extremely clever uses of additive, either alone or hybridized with other tools, for composite layup tooling, producing some very interesting carbon, glass and aramid (Kevlar) parts. Likewise, end uses can be hybridized, with additive-manufactured complex ends added to shafts or beams made by winding filament or tow around a simple metal mandrel.

A .pdf of Dobstetter’s presentation is found here in the archives of the 2013 Armament conference.

Additive Manufacturing for Aerospace

MIT Technology Review has an interesting article (aren’t they all? Well, in MIT Tech Review, maybe) called Additive Manufacturing Is Reshaping Aviation. In this case, they’re not talking about little piston-plane builders like Evektor or Cirrus, but the big gorillas of jet-engine production, Pratt & Whitney and GE.

prattwhitneyx299Pratt & Whitney already uses two additive manufacturing techniques to make some engine components. Instead of casting metal in a mold, the methods involve forming solid objects by partially melting a metal powder with either a laser or an electron beam.

Additive manufacturing processes can reduce waste, speed up production, and enable designs that might not be feasible with conventional production processes.

Ding ding ding… we have frequently mentioned this benefit, the ability to design things free of the shackles of traditional subtractive manufacturing.

The novel shapes and unusual material properties the technology makes possible—such as propeller blades optimized for strength at one end and flexibility at the other—could change the way airplanes are designed.

Of course, propeller blades are already optimized that way, by having taper in three dimensions. And a company named Carter Aviation Technologies has developed revolutionary propellers that use a flexible composite skin around two spars that flex like the bones in your forearm to change the delta of pitch in the propeller, whereas conventional propellers can only change the pitch itself, not its rate of change. (Hey, you could use the additive tooling that Dobstetter showed in the first cite to make all the iterations of a Carter-patent propeller that you could possibly use).

Meanwhile, engineers hold out hope for today’s amazing technology to be supplanted by better machinery — finer resolution, faster printing, better-understood statics & mechanics. Even as great as the state of the art is, the engineers must push it:

…additive manufacturing techniques need to improve to allow for higher precision. Once researchers understand the fine, molecular-scale physics of how lasers and electron beams interact with powders, [P&W engineer Frank Prelli] says, “that will lead to the ability to put in finer and finer features, and faster and faster deposition rates.”

Whatever happens with the jet engine makers and the airframers that are their major customers, we can expect more and better from additive manufacturing. While the whole thrust of the article is aerospace, it has clear applications to defense and firearms manufacturing.

And A Bonus from MIT Tech Review: Nanosteel

What happens to steel when you apply nanotechnology to it?

MIT Tech Review’s Kevin Bullis (same guy that wrote the additive article linked above) is saying things that scarcely seem possible:

An inexpensive new process can increase the strength of metals such as steel by as much as 10 times…

Can you think of a firearms application for that? Or about 100 of them? We sure can. (Saving 90% of the weight of a Browning MG in .338 LM?)

But wait! It turns out it doesn’t just strengthen the steel… it also makes it much more corrosion-resistant. It works by electroplating nanometer-thing material onto a part in nano-engineered layers. It has the effect of changing the apparent properties of the now-hybridized part.

And it’s not significantly more expensive than current plating and coating processes.

Developments in Steel Armor

Some time ago we covered the types of Armor available to vehicle designers through World War II and explained why penetration of Rolled Homogeneous Armor, then state-of-the-art, is still routinely used as a standard measuring stick for armor penetration. But while RHA was the tank skin of choice in 1945 (with cast armor used for specific purposes, and face- (aka flame-) hardened armor on the way out), armor developments didn’t stand still then.

By the 1970s, British research had produced composite armors that were more effective, especially against Monroe effect shaped charges, than RHA. The British armor and its American derivatives (British government researchers shared their discoveries freely with US Army engineers and contractors on the M1 Tank and M2 Bradley contracts) were developed under conditions of great secrecy and remain, in detail, classified. You can find generalities about how they work online and in specialty books.

But the development even of steel armor did not stop with RHA. Since the end of World War II, steel makers and AFV engineers have pursued harder armors, called in English High Hardness Armor (HHA) and Dual Hardness Armor. These armors are challenging to produce, because increasing armor hardness risks embrittlement of the metal. Recently, a Swedish steelmaker has gone further in developing Ultra High Hardness Armor (UHH).

HHA is described by the military standard MIL-DTL-46100E, and offers a hardness range of 477–534 Brinell hardness number (BHN).

DHA is described by the military standard MIL-A-46099C. DHA is produced by roll bonding a 601–712 BHN front plate to a 461–534 BHN back plate; this gives the armor an extremely hard layer bonded to a hard-but-tougher layer. (That is, of course, reminiscent of WWI and early WWII face-hardened armor, where a more ductile, less hard, metal panel would be hardened to 500-700 BHN, but just a few millimeters deep). By fusing two different hardnesses of steel into a single plate, they produce a heterogeneous armor plate with both the ability to resist penetration by a hit (which comes from hardness) but also, without cracking (which comes from ductility).

UHH describes monolithic (probably. homogeneous) armor plate of greater than 600 BHN. The Swedish firm, SSAB Oxelosund AB, has developed two commercial grades of UHH, one, Armox 600T, offering Brinell 600 hardness, and an even harder plate called Armox 600 Advance offering an extrapolated BHN of over 650. (For those of you comfortable with the Rockwell hardness scale, Armox 600 Advance equates to RC 58-63. The armor production process for Armox seems, to the limited extent the Swedes have released it, conventional.

ssab_hha_armor_production

Despite their conventional-appearing production process, these armors are remarkable. To achieve penetration half the time, of 8mm (!) of Armox 600 Advance set at a 30º angle, a .30 caliber AP projectile must be traveling ~860 m/s — which is faster than the muzzle velocity of most .30 firearms (a 7.62 x 54 mm PKM is about 820-825 m/s). It protects against a .50, half the time, to about fps; to protect against .50 AP to 820 fps you need to step up to 12mm (.465″) plate. These are WWI tank and WWII light-tank thicknesses of armor, with much better defensive performance than the RHA and FHA of that period.

7mm Armox 600T stopped 4 of 7 .30 rounds.

7mm Armox 600T stopped 4 of 7 .30 rounds from any penetration, and the other three’s penrtration was nugatory.

 

Another way of taking a broad view of the performance of UHH is that across the board, there is an advantage of about 120 m/s or 400 fps difference in the velocity of impact that this armor will shrug off, vs. the MIL-STD for HHA.

Cal. .50 AP had its way with 8mm 600T -- half the time.

Cal. .50 AP had its way with 8mm 600T — half the time.

There is an excellent report from 2008 on DTIC (clicking downloads .pdf) on the evaluation of Armox 600T and Armox Advance, Ballistic Testing of SSAB Ultra-High-Hardness Steel for Armor Applications. The purpose of this evaluation was to help set up a MIL-STD for Ultra High Hardness Armor; one outcome of that is the detail standard, MIL-DTL-32332 (MR) 24 July 2009. Detail Specification: Armor Plate, Steel, Wrought, Ultra-High-Hardness (link to everyspec.com).

Note spalling on Armox Advance. It was also somewhat prone to cracking, if the edges of the plate weren't properly dressed.

Note spalling on Armox Advance, which would create secondary fragmentation in an armored vehicle. Advance was also somewhat prone to cracking, if the edges of the plate weren’t properly dressed.

Customizing your Carbine: Pro and Con

1959 ChevyIn 1959, a General Motors executive boasted that there were so many options available to buyers of the 1959 Chevrolet, that it was theoretically possible for no two of the hundreds of thousands of Chevies delivered that year to be alike. (In fact, many popular configurations were made in vast quantity, and many theoretical combinations of options made no practical sense and were never built). It’s quite a difference from today, when you have red, white, black, silver, and Option Package A or Option Package B. The new way of doing things substitutes soulless modern efficiency for funky 20th-Century soul.

Sometimes it seems like there are more ways to customize an AR type carbine than there were for that ’59 Chevy buyer. Oddly enough, the AR and the ’59 Chev are near-contemporaries, too; but initially, there was nothing but factory standard parts for the rifle. The military was offered an evolutionary/revolutionary  CAR-15 “system” with submachine-gun, rifle, carbine, and LMG versions, and apart from 10,000 SMGs for special purpose units, they didn’t buy.  Civilians could buy a Colt SP1 Sporter until the 1980s, when they got the option of a CAR-15 inspired SP1 Carbine, and they could customize either only with surplus parts or knockoffs of them.

CAR-15 Family

 

The first real mods that tried to extend the gun came in the 1970s, with things like the Rhino gas piston conversion, and the 6x45mm round. Both are forgotten now, but led the way for many subsequent attempts to pistonize the AR and to fit it with alternative components. That was 40 years ago. The AR is now recognized not as a single rifle or even as a CAR-15-style “family” but as a highly modular shelf full of

ar15newsdotcomNow, there are so many new AR parts all the time there’s even a website devoted to the announcements, AR15News.com. A quick look at the parts being promoted there suggests that even today, add-on parts fall into two categories:

  1. Personalizations that modify the gun in a way that pleases its owner; and
  2. Modifications that are meant to change the basic function of the gun.

Here’s an example of the former: the DS Arms “bufferloc” kit. (And here’s it’s press release on the aforementioned AR15News). It claims a number of benefits, but the one we see as real is that a nose-heavy upper doesn’t swing sharply open when the rear pin is pushed out. This is a minor aggravation, but a real one. Some of the other claims seem to use to either be (1) theoretical, not data-based’ and (2) beneficial only if the gun is not made right in the first place. (For example, they claim to prevent carrier tilt, something that’s not a problem in ordinary direct impingement ARs, if they’re built to spec).

We don’t mean to bag on DSA. They’ve been around for a while, and build some high-quality products. We can vouch for their RPDs and FALs, for instance. But their latest accessory got us thinking about accessories, period.

Accessories: everybody loves ‘em. AR gadgets are to guys (and some gals) like high heels are to many other gals’ closets (and some guys’, probably; it’s a free country, but we really don’t want to know). Gun folk no more explain to shoe folk the difference between our AR uppers than they can explain the difference between this year’s and last year’s Manolos.

If you want an accessory, by all means get it, and try it out. If it’s your gun, you only use it by yourself, and it makes you happy, that’s the only criterion you need to meet. But if you work with a team, or if you’re buying for a department, unit or agency, there are a number of reasons to go slow on buying cool AR stuff.

  1. Uniformity of weapons has its benefits. If one of you is out of the fight, perhaps because he’s wounded, performing a specialty task (medic, breacher) or communicating with higher, interoperability of weapons with the shooters actually shooting means the non-fighting guy’s guns and ammo become a potential New York reload for the fighting guy. (One combat duty of NCOs in the US forces is accountability and cross-leveling of weapons and ammo). There is no feeling so stupid as holding a strange gun and looking at a strange optic, unsure which button turns the illuminated reticle on (and worse, what turns it on on the NVG setting as opposed to the one that lights up your face for the enemy).
  2. Personalization limits resale appeal. While you can sell a generic M4 knockoff to anyone looking for a generic AR, your potential buyer pool shrinks with each add-on, proportional to the distance of that add-on from the norm. Fewer buyers = less demand = less support for a premium price. Paradoxically, spending thousands to accessorize a gun may decrease the prospects, and economics, of selling it.
  3. Accessories never add their own value to a gun. It’s strange the way that works, but a $2,000 AR with $2,000 in premium accessories changes hands for $2,100 all the time. A $1,500 gun with a $100 ambi selector and a $300 drop-in match trigger is a $1,500 gun. You’re never going to get the price of that Larue mount for your ACOG back. So do you buy the Larue or stick with the factory two-knob job? Depends. If your mission means optics are on-again, off-again, you’re going to love the Larue. If you set-it-and-forget-it (for instance, if you use other NODS tandem with the ACOG, and don’t have to swap on and off), then the Larue is of small benefit to you.
  4. Odd calibers make great stories, but we’ve learned some things from the 2012-13 ammo shortage. In a panic, common calibers disappear first as hoarders grab them. But much larger quantities of common calibers are kept on hand. At the peak of the empty-shelves period, the oddball rounds that were available varied widely from one shop to another. In one geographical area, you could still find .300 Blackout and 6.8 SPC; in another, you could find no “near-military” calibers like that, but only hunting ammo for such rounds as .243 Winchester. An odd caliber is, unless you’re standardizing it across an agency, a  permanent supply and interoperability problem.

So can we boil it down to one pithy phrase? As it happens, we can. For “hobby” ARs, suit yourself. For combat-oriented ARs, figure out where the center of the unit/team/market is, and deviate from that point only after careful consideration.

If you are that guy who wants to run an EOTech when everyone else is running an Aimpoint, that’s OK, but it’s on you to make sure the other guys are comfortable with your holographic sight — and that you have spare batteries at hand. An illuminated optic that isn’t subject to frequent preventive-maintenance inspections is nothing but a device for storing dead batteries.

3D Printing in Metal, What’s New?

Last year we saw several developments that hinted that 3-D printing was coming in metals. Of course metal 3-D printing is fairly common now, using various modes of laser sintering, but the promise of 2014 was that consumer level (or at least prosumer) 3D printing in structural metals was a possibility.

And that’s where it was as 2015 dawned: “possibility”. Three big shakers of 2014 were:

  •  A team at the Sustainability Lab at Michigan Technical University, using a Rostock based deltabot to deposit material from a welder;
  • A company called Weld3D which meant to commercialize technology similar to MTU’s; and,
  • a student project at the Technical University at Delft, Netherlands, which combined a RepRap Prusa mechanism and software with a MIG welder;
The MTU inverted Rostock deltabot system. Fixes the heavy weld gun in place, moves the work platform. Click to enlarge.

The MTU inverted Rostock deltabot system. Fixes the heavy weld gun in place, moves the work platform. Click to enlarge.

The TU-Delft project is on hold, pending a new intake of undergrads to play with it and perhaps take it in a new direction. It never proceeded beyond printing a few homely and ragged walls, but it was a proof of concept.

The Weld3D project shows no signs of change at its website. We’ve messaged them for information, and we’ll share what we can.

And that leaves the MTU project, which has a new paper in the December 3D Printing and Additive Manufacturing (which they just emailed us about this week). In this paper, they’re dealing with the issue of “substrate” — the plate that they print upon, in their design, a metal plate.

As everyone who’s done 3D printing with basic plastic Fused Deposition Modeling (FDM) processes knows, the base you print upon is vital. Some materials stick to some bases, and your print gets destroyed when you try to removed it. Others don’t stick, and the corners curl up, leading to the same ultimate result — a scrap print.

As you might imagine, inert-gas metal-arc additive manufacturing is just as sensitive to substrate as common ABS and PLA printing is. A major problem is burning through the substrate; another is, as you might expect from a welding-based solution, adhering to it. (You want the layers of your metal part welded to each other, not to your 3D printer, right?)

In this experiment, Amberlee Haselhun and six collaborators from the Michigan Technical University Materials Science and EE/CE Engineering departments examined how to make weld-manufactured aluminum parts not stick to their substrate, and found a best-possible and most-economical possible solution. Additionally, these solutions are fully in keeping with the Sustainability Lab’s devotion to manufacturing technologies that can be employed with minimal demands on infrastructure and minimal environmental disruption.

Gold in the Introduction

Before we get to the experiment and its conclusions, we should mention the brilliant, concise introduction, which breaks down “3D Metal Printing” by commercialized technology (numbering of list ours, and citations deleted):

3D metal printing is commercially available in several forms:

  1. laser-based additive manufacturing,
  2. weld-based additive manufacturing, and
  3. shape deposition modeling.

Laser-based additive manufacturing methods include powder bed fusion (direct metal laser sintering), selective laser sintering, selective laser melting, and directed energy deposition (laser cladding).These methods offer excellent dimensional control but have large production costs due to the use of lasers or metal powders.

And then introduces a taxonomy of weld-based (and potentially lower-cost) additive manufacturing.

Weld-based additive manufacturing methods include gas metal arc welding (GMAW), gas tungsten arc welding, directed energy deposition and powder bed fusion (electron beam melting), electron beam freeform fabrication, and microwelding in a single-layer multipass welding regime. Parts produced by weld-based additive manufacturing are inexpensive and nonporous with good interlayer adhesion, but have a limited print resolution and poor surface finish. Microwelding is the exception, exhibiting excellent dimensional control and finer surface finish resulting from the small-diameter electrode and wire employed.

(Hmmm. We’ll have to look into this microwelding juju). Note that what they call GMAW, welders call MIG welding, and what they call “gas tungesten arc” is commonly called TIG welding. If everybody could speak the lingo, it wouldn’t be grad school, eh.

The introduction then notes that, “Shape deposition manufacturing processes feature both additive and subtractive manufacturing.” We’d note that Weld3D’s rocket nozzle proof-of concept seems to be this sort of part, having been rough-formed by weld-based additive manufacturing, and then turned to final size, shape and finish (at least, on the outside). While the inside of the part they have shown was not (yet?) turned or finished, one can clearly see that this is a potential method for making a de Laval type rocket nozzle with considerably less waste than milling from billet would produce.

The Experiment

The MTU printer’s current iteration is  based on an inverted Rostock Deltabot, with a more solid frame moving the work platform under a gas metal arc welding (GMAW) weld gun fixed in 3-dimensional space. (In a normal Rostock, the print head moves and the work platform stands still. This one is inverted because of the weight and inertia of the print head — the heavy Spoolmate 100 weld gun).

In the experiment they used 0.030″ 1100 aluminum welding wire and laid down a simple block of aluminum on two different materials with three different coatings each. The materials were 1100 aluminum and A36 steel. 1100 is almost pure aluminum — 99% pure, minimum, and it is the strongest commercially pure alloy: it’s highly conductive, extremely corrosion resistant, and easily worked. It won’t take heat-treatment and is not much used in structural applications. Conversely, A36 is a common structural steel, often used in I-beams and building frames and that sort of thing.

Each substrate material was tested bare, with an 18.8 µm aluminum oxide coating, and a spray-on boron nitride coating.

Conclusions? The graphic shows the essence of it. The steel substrate was better than the aluminum across the board; the boron nitride was the best coating, but bare steel works OK.

Sub-release

Solving the substrate-adhesion problem — not just for 1100, but for all materials we want to print — is just one of many small steps that must be taken before you can plug something into your USB port and print a hammer (or a Yoda head) in metal.  (That printed R2D2s and Yodas are essential sample prints on everybody’s websites says something about the lonely lives of engineers and scientists, eh?)

What Else is in the December 3DP?

The current issue also has several other interesting articles, including a history of National Science Foundation support for the development of this technology, and some preliminary plans for how one might 3D print objects made of more than one material (analogous to using inserts in cast or injection-molded parts). Unfortunately these articles are only available to subscribers (very expensive) or by paying the rather stiff rates ($474!) for access. Editor Hod Lipson has done an excellent job of finding and publishing worthwhile technical articles, but the economics of academic publishing (low volume, high costs) means that most of the people who would benefit from this knowledge struggle to get at it.

Still, there’s nothing like progress, which for us means less silly slogans shouted by silly politicians, and more, the strides made by scientists and engineers.

Soviet ATGMs and October, 1973 (Long)

So far in this series, we’ve looked at the development of US and Western European anti-tank guided missiles, from their origins in a German WWII design program to their introduction to combat — just in time to encounter Russian missiles designed along similar lines — in the Vietnam War. (The Russian missiles got the first kill, by a couple of weeks). Today we’ll extend the story of early ATGMs by discussing how the Russians developed their missiles, and how Russian missiles figured in Arab planning for in the Yom Kippur War (the Ramadan War, to the Arabs, and the October War to the strictly neutral) of 1973. Unlike the Vietnam offensive of 1972, where they were only locally decisive, the robotic tank-killers decided battles and nearly won the war. We’ll have more about the war in a future installment (this one is already over 2500 words — oversized for a web post).

AT-3 Sagger (this one an improved Chinese copy).

AT-3 Sagger (this one an improved Chinese copy with a much larger, stabilized sight and SACLOS guidance).

Russian Missile Development

Compared to Germany, which was  working on them in 1945, and France and the USA, which were in development from the earliest 1950s, the Soviets were a little late to wire-guided ATGM development, beginning only in the late 1950s. It’s unknown whether they had as a basis any foreign technology. Certainly they could have used captured German technology, French or American technology acquired by espionage, or they simply could have applied robust Russian engineering to problem solutions that they knew their Western rivals had already accomplished. It’s probable that all three were part of missile R&D, with the heavy lifting being done by Russian engineers. The Russian product, by 1973, was a missile that was combat-ready and had several advantages over its Western counterparts.

AT-1 Snapper live fire, somewhere in Europe. This is the BRDM-mounted version.

AT-1 Snapper live fire, somewhere in Europe. This is the BRDM-mounted version.

As with SAMs, Russian engineers passed through numerous experimental iterations of ATGMs (Anti Tank Guided Missiles), and they delivered to their Arab friends the first and third version that they operationalized. The first missile was a bit of a turkey; fired from a converted GAZ-69 jeep, the 3M6 Shmel (NATO coded, AT-1 Snapper) flew fairly slowly, had an enormous launch signature, and was vulnerable to the obvious countermeasure of blowing away the jeep and its crew, including the missile aimer who could not fire from a remote or dismounted position, but sat in a seat facing backwards looking at the target through a periscopic sight. The gunner had to continue to aim at the tank and steer the missile throughout its flight, which could be 15-20 seconds — a lifetime, literally, in armored combat.

It is very hazardous being on a tank battlefield wearing less than a tank. A cotton Army shirt, or a sheet-metal jeep, provide no protection and if that’s what you have, cover and concealment are vital. The Snapper couldn’t be fired from cover (except in its BRDM version, which put a bare 15mm of armor between the operators and the great outdoors), and it negated its own concealment by launching from the control station.

The third missile, though, the 9M14 Malyutka, better known by its NATO reporting code AT-3 Sagger was a hit, no pun intended. The Sagger, while having a great resemblance to the French missiles the Israelis had played with and a family resemblance to the Snapper, was small. It came packed in a plastic “suitcase” half of which served as the base for its simple rail launcher, and the other half as a base for its reusable sight. One man could carry one all day on his back, and two, suitcase-style, in his hands for short spurts. In true Russian tradition, the missile was sturdy and reliable, and made no superhuman demands on its operator. True, it was a MCLOS (Manual Command to Line of Sight) missile, at least in these early versions, and operator training was vital, but along with the missiles, the Soviets had developed operator and maintenance training, including mobile missile simulators that could travel with divisional logistics elements and keep operators sharp. These they furnished freely to the Egyptian and Syrian armed forces (among others). It was the Egyptians who would make the best use of these missiles.

The Sagger and the Tank Sack

Soviet doctrine had long taught the anti-tank ambush under various terms (the image-rich “tank sack” is one that springs to mind), and they’d used it deftly against the Germans, whose armored warfare worked splendidly against Russian tanks, and not so well against concealed AT guns attacking the Panzers’ vulnerable flanks.

Chinese improved Sagger live fire.

Chinese improved Sagger live fire.

The modern variation of the use of AT guns was to follow leading tanks closely with infantry antitank teams. Soviet tanks would have their flanks guarded by infantry, something comforting for any tanker, but these infantry would be well-equipped with AT weapons, principally long-range Saggers and short-range RPGs. A Sagger crewman needed intensive initial and recurrent training, and the Russians developed an innovative series of portable simulators to keep their missileers sharp without expending vast quantities of costly missiles. The well-trained Sagger crews dug in and/or located on reverse slopes, with their missiles displaced to the limit of their cords (about 15m) and only their periscopes showing. This protected them better than their unlucky mates in the Snapper jeeps.

The Soviet-designed weapons had a minimum effective range, but more to the point their maximum effective range was 3,000 meters, on the ragged edge of the effective range of the West’s 105mm tank gun. Moreover, a tank gun’s accuracy against a moving target depends on accurately ranging and leading the target, and so, a tank gun’s accuracy declines with range, and declines precipitously with range on fast-moving targets. This period US chart NOTE 2 brags up the improvement in a pH from Sherman to Pershing to M60A1 days:

post_wwii_tank_cannon_improvement

But a missile under human guidance, like the Sagger, can track a moving target even if the target changes direction or speed. The general rule of thumb is that the first hit decides a tank fight; Sagger had a near 90% probability of hit at all ranges from 1,000 to 3,000 meters.

sagger_first_round_ph_small

 

A hit gave the Sagger a very high pK as well: the warhead was among the most effective in the world at the time, penetrating the equivalent of 17″ of rolled homogeneous armor at 0º obliquity (engineering speak for “square on”). US testing of captured Saggers and computer probability analyses assigned the Sagger a .67 pK at a mean engagement range of 2,500 meters.

Combined with the T-62’s 5000+ fps tank guns for the midrange and RPGs for the knife fight, the Sagger meant a Soviet-style (including Egyptian or Syrian) antitank ambush was potentially lethal from 3,000 meters to zero.

soviet_weapons_ph_all_weapons

American soldiers and engineers were very impressed with that graph.

Soviet technology made the combined arms army of 1970 very different from the victorious horde of 1945, Unlike the Western Allies, who had advanced under an umbrella of air power, the Soviets chose not to depend on their powerful Air Forces and Frontal Aviation, but to give their tank and motorized rifle units an umbrella of surface-to-air missiles overhead and a screen of anti-tank missiles to the front. They equipped every tank with night vision, choosing to spend now on active infrared rather than wait for the costs of image intensification to come down (the West, mostly, made the other choice, to delay purchases now and skip a generation of night equipment). This would also shock Israel, when her enemies (especially the Syrians, who had trained with the night sights and lights very extensively) could see at night, and their army could not. The IDF was heir to a tradition of night-fighting from 1948, and its leaders firmly believed that Arabs were too frightened and superstitious to fight at night, just as they believed that Arabs couldn’t operate and maintain sophisticated missiles.

The Sagger Countermeasures of 1973

Before the war, the Israelis didn’t take the Sagger seriously. They knew about it from desultory US reports and from occasional firings during Suez skirmishes — inconsequential firings that encouraged them to disrespect the missile. It was just one more anti-tank weapon, and when their own forces wanted anti-tank weapons, the Deputy Chief of Staff told them, “You already have the best one: a tank!” The qualitative change in the battlefield produced by a long-range, accurate, tank-killing weapon was completely unexpected.

[Military Intelligence] printed booklets about the Sagger’s characteristics based on information received from the United States, which had encountered the missile in Vietnam in 1971. The armored corps command had even developed tactics for dealing with the missile. But neither the booklets nor the suggested tactics had yet filtered down and few tank men were even aware of the Sagger’s existence.NOTE 3

How to answer the Sagger attack would become a major question for the Israelis (and by extension, for anyone who might have to fight Soviet-style forces). The US also studied this, before and after the war. While defenders worked out some countermeasures, they were imperfect; but a decade later, American tankers were still using “Sagger drills” developed by surviving Israeli tankers after their counterattack of 7 October 73 was savaged by infantry anti-tank teams using Saggers and RPGs.

Reshef’s operations officer, Lt. Pinhas Bar, who had accompanied Bardash’s force, assembled the tank commanders and explained the techniques developed in the past few hours for coping with the Sagger. Such impromptu lessons would be going on all along the front as new units took the field alongside tankers who had survived the day.

The Saggers, the “veterans” explained, were a formidable danger but not an ultimate weapon. They could be seen in flight and were slow enough to dodge. It took at least ten seconds for a missile to complete its flight—at extreme range it could be twice that—during which time the Sagger operator had to keep the target in his sights as he guided the missile by the bright red light on its tail. From the side it was easy for the tankers to see the light. As soon as anyone shouted “Missile,” the tanks were to begin moving back and forth in order not to present a stationary target. Movement would also throw up dust that would cloud the Sagger operator’s view. Simultaneously, the tank should fire in his presumed direction, which itself could be sufficient to throw him off his aim.

It was clear to the tank crews that something revolutionary was happening—as revolutionary, it seemed, as the introduction of the machine gun or the demise of the horse cavalry. Tanks, which had stalked the world’s battlefields for half a century like antedeluvian beasts, were now being felled with ease by ordinary foot soldiers. It would take time, in some cases days, before the implications of this extraordinary development would be grasped by higher command. Meanwhile, the tankers would have to figure out for themselves how to survive. NOTE 4

Most of the countermeasures relied on spotting the backblast of the launch and directing fire in that area. The US noted with alarm that the M60A1 tank needed to close to 1000-1500 meters to get its pH up to 50%, and by that point it was well within the range fan of the Sagger. 

The Sagger remains in use, here in former Yugoslavia. Note the "suitcase" halves for scale.

The Sagger remains in use, here in former Yugoslavia. Note the “suitcase” halves for scale.

Other Sagger countermeasures included laying suppressive fire on likely lurking spots, something the US Army had forgotten since World War II and Korea; exploiting terrain, or as the Army put it, “every fold of ground”; keeping formations loose and non-geometric in order to complicate a Sagger gunner’s second-choice if he lost his first target; keeping moving, or firing from hull defilade; and using infantry for close-in protection of tanks. The US had a few advantages, too: its similar suite of missiles, guns and unguided rocket AT weapons had fewer minimum-range problems and generally superior accuracy and reduced training demands.

Even after the war, the Israelis struggled to find countermeasures. Uzi Eliam remembers:

Egyptian infantry infantry forces with Saturn missiles constituted a serious threat to our tanks. Maj. Gen. Albert Mendler, commander of the Southern division (the 252nd) in the Sinai Peninsula, was hit by a Egyptian antitank missile and died of his injuries…. NOTE 5

[Deputy CGS Israel] Tal was extremely concerned about the threat of the Sagger missiles which he himself had not completely understood before the war. During the years of the War of Attrition along the Canal, our observation posts had observed closed train cars arriving at the front lines. Each time such a train car reached the position of an Egyptian military unit, a long line of soldiers would form near the door, and the soldiers would enter the car one at a time. At first, we made jokes about the train cars, referring to them as mobile sexual service units similar to the kind operated by the Syrian army before the Six-Day War. However, we quickly realized that the train cars contained training simulators for Sagger missile operators.

At R&D, we thought about different ways of addressing the threat with the American developed Mk19 40 mm grenade machine gun. This machine gun was vehicle mounted, and had a firing rate of 350 grenades a minute and a range of 1500 m. … The proposal to add the system to our armored vehicles was decisively rejected by Operations Branch Chief Tal. According to his dogma, what he called “foreign elements” could not be introduced into tank battles.

Although we started searching for a technological solution to the SAG or missile about 10 days after the outbreak of the war the moment the first missiles fell into our hands, we were unable to find a shortcut or a quick solution…. Tal now invoked his authority as Deputy CGS… [with others]… he put all his energy into finding a solution to the problem. The solution he selected involved positioning net fences and coiled barbed wire around tank encampments in order to cause early detonation of fired Sagger missiles before they hit the tanks themselves. NOTE 6.

Despite our best efforts it took more time to develop responses to the Sagger missile. Many ideas were tried… including the possibility of disrupting the missile command system in midflight, misdirecting the missile navigator, and physically obstructing the missile with a steel net in close proximity of the target. The simple Russian missile was not susceptible to our disruption efforts, and we only found a proper solution to the threat posed by the Sagger missile years later. NOTE 7.

But of course, the Russians were not sleeping, and they had better weapons on the drawing board, already. But that’s another story, perhaps for some other day.

Meanwhile their 1973-vintage missiles were a key to the Arab nations’ hopes to recover territory, and pride, lost in the calamitous defeat of 1967. That’s the next, and we think last, installment of this story, the story of early ATGMs.

Notes

  1. Eilam disagrees with this, noting that US policy was only to provide new technology to Israel once the Israelis had shown themselves capable of producing their own, in order to discourage “escalation” and an “arms race.” These are diplomatic (i.e., State Department) terms; while the US DOD then strongly slanted towards Israel, State was then (as now) a hotbed of antisemitism and anti-Israeli feeling.
  2. All these charts come from US Army, TRADOC Bulletin 1u, and were originally prepared as briefing view-graphs (powerpoint before there was powerpoint).
  3. Rabinovich, Kindle Locations 653-655
  4. Rabinovich, Kindle Locations 2092-2108.
  5. Eilam, p. 108.
  6. Eilam, pp. 138-139.
  7. Eilam, p. 148.

Sources

Kelly, Orr. King of the Killing Zone: The Story of the M1, America’s Super Tank. New York: WW Norton & Co., 1989.

Eliam, Uzi. Eliam’s Arc: How Israel Became a Military Technology Powerhouse. Sussex University Press, 2011.

Rabinovich, Abraham. The Yom Kippur War: The Epic Encounter That Transformed the Middle East. Knopf Doubleday Publishing Group. Kindle Edition.

US Army, Training and Doctrine Command. TRADOC Bulletin 1u: Range and Lethality of US and Soviet Anti-Armor Weapons. Ft. Monroe, VA: TRADOC, 30 September 1975. Retrieved from: http://www.dtic.mil/dtic/tr/fulltext/u2/a392784.pdf

What’s Up in the 3D Printed Gun World?

Time for an update, eh?

WarFairy Lower Banner

We’ve been seeing really creative AR lowers for a while now. A lot of the greatest ingenuity, like the FN-inspired creations above, come from the innovator who calls himself Shanrilivan and his creative entity WarFairy Arms. Watching his Twitter feed, or @FOSSCAD’s, is a good way to keep up with what’s coming from the community. (Coming soon: AR and AK fire control groups, for example):

AR fire control group

If you think there’s no innovation happening in firearms, you’re not tapped into the maker community inside the gun community — or is it, the gun community inside the maker community?

Some Words about Development

These lowers are not being “engineered” in any real sense of the word. Instead they’re being designed, and are then being tested, in a very tight closed-loop development cycle. From lowers that busted in a couple of shots, we’ve got lowers that have endured thousands of rounds. And that look stylish. This pastel AR has a printed lower and printed magazine.

printed lower and mag

It’s ready for its close-up, Mr De Mille:

printed lower and mag closeup

To see about 15 more pictures of printed-gun developments, including magazines, a 7.62mm lower, a revolver, and more, click the “More” button.

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Anti-Tank Missiles — America’s Early Years

We’ve discussed the original German developments on wire-guided missiles, and the way the US Army didn’t pick uo on them until it was imagining its ultimate tank-killer in the late 1950s. That missile program was rolled into one of Robert S. Macnamara’s grandiose schemes, the international MBT-70 tank, that was going to be the best tank in the world by such a margin that all NATO would adopt it. (Instead, it wound up being a bitter, painful and costly learning experience for the US and Germany).

A Note About Interational and Combination Programs

International programs always have great appeal to deskbound defense intellectuals like Macnamara. It’s an instantation of a set they can’t resist, making one general thing replace two or more specialized ones. Therefore it’s always easy to sell DOD suits on something like the M14 replacing the M1 rifle, M1 carbine, M3A1 SMG, M1918A2 automatic rifle, and M1919A6 squad machine gun, all in one fell swoop.  The problem is, of course, that the M14 was okay to replace the rifle and maybe the carbine, but couldn’t quite do what the grease gun and the BAR did, and was not even in the same game, capability-wise, as the light machine gun. This is not a criticism of the M14, it’s a criticism of the boneheaded idea that a general-purpose rifle can replace something developed for another general-purpose entirely. From the beginning the M14 was intended to replace the M3A1 as well as the M1 rifle, but it wound up being longer and bulkier than the M1, something many people don’t understand because of the M14’s clean, attractive, carbine-like lines.

While the graveyards of defense procurement are rich in “not just a toaster, but also a blender!” false starts, the problems of neither-fish-nor-fowl procurement are compounded by international programs. Now you have to deal with different requirements that are rooted in different doctrines and even concepts of war. The MBT-70 was the compromise hellchild of incompatible American and German concepts of what a tank was for. The Americans envisioned a tank so good it could fight and win despite being grossly outnumbered, and that fired missiles. The Germans, having tramped that road to its logical conclusion in WWII, wanted a tank they could afford to build in such quantity that they wouldn’t have to fight grossly outnumbered, and they saw the tank-gun-missile-launcher as the boondoggle it was. NATO politics forced both nations, whose armies had a tradition of mobile, offensive-oriented tank fighting, onto a war plan comprising static defense in place. So the best tank minds of two of the world’s top five tank-fighting nations poured themselves for years into a project whose demise was written in its congenital deformation.

As a rule of thumb, odds of failure of a given military procurement project increase by the exponent of the number of armed services involved.

Meanwhile, Back in La Belle France…

While the Americans and Germans tied themselves into knots trying to make a Ronco does-everything tank (and the Americans, to build a missile it could launch), something interesting happened in France. French engineers picked up where Dr Kramer left off with his wire-guided AT missile. Within a few years, they had a design for one that would work, and they showed it off to their allies, hoping for some help. So, about 1951, French officials showed American officers the experimental SS-10 missile. It was a small, barely man-portable or jeep-launched missile that could deliver a whopping hollow charge onto a tank with precision, given a well-trained operator.

SS-10 in US service in 1961. With its ends popped off and propped up with a built-in monopod, the box became a launcher.

SS-10 in US service in 1961. With its ends popped off and propped up with a built-in monopod, the box became a launcher.

Nord Aviation (the French manufacturer) missile ad, 1959.

Nord Aviation (the French manufacturer) missile ad, 1959. Click to embiggen.

The SS-10 incorporated Manual Command to Line of Sight or MCLOS guidance. A sodium flare in the missile’s tail let the missileer steer the weapon, which he flew onto target with a joystick. (This was generally how Kramer’s system had worked). The weapon came to American attention in 1951, according to a once-classified US history:

The French SS-10 missile evolved from the German RuhrstahZ, or X-4, a single-wing, wire-guided, roll-stabilized missile originally developed as an air-to-air missile late in World War 11. The Germans were ready to begin mass production of the Y-4 early in 1945, but their plans were interrupted by costly delays in acquir- ing suitable solid-fuel rocket engines and by the relentless bombing of research and manufacturing centers by Allied planes. Recognizing the potentialities of the X-4 as a surface-to-surface antitank weapon, the French continued-its development after the war ended.lO The resultant product was the SS-10, a ground- launched, cruciform-wing missile about 34 inches long with a 30-inch wing span. It had a gross weight of 34 pounds and carried an 8.9-pound shaped-charged warhead for an operational range of about 1,500 yards. Like the X-4, the SS-10 was an optically-guided, wire-controlled missile — features later incorporated i n the DART guided missile system.

The Ordnance Corps became interested in the SS-10 a s a potential antitank weapon late in 1951 and subsequently supported the development program with primary emphasis on procurement, test, and evaluation of the system. Early in 1952, 500 SS-10 missiles and 3 sets of ground equipment were procured from the French Government for use in evaluation tests by the Ordnance Corps at Aberdeen Proving Ground, the AFF Board No. 3 at Fort Benning, Georgia, and the U. S. Marine Corps at Quantico, Virginia. The evaluation program began in December 1952 and continued until October 1953, when it was discontinued because of unfavorable test results. Members of the AFF Board No. 3 recommended that the SS-10 missile, in its current state of development, be considered unsuitable for use by the U. S. Army, and that future French development of the missile be carefully observed with a view to reconsideration of the weapon if an improved model should be produced before a comparable American weapon became available.

Click “more” to continue with the Comparable American Weapon — a dead-end — and America’s return to French missiles for the 1960s, and developments to the early 70s.

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