The Spanish conquistador helmet wasn’t worn by Cortez or Pizarro

Tuesday, May 15th, 2018

Someone mentioned “Spanish conquistador helmets” on Twitter, and I helpfully added that the iconic helmet is known as a morion. What I didn’t realize is that the Spanish conquistador helmet wasn’t worn by the Spanish conquistadors we’ve all heard of:

The iconic morion, though popularly identified with early Spanish explorers and conquistadors, was not in use as early as the conquest of Mexico by Hernan Cortez or Francisco Pizarro’s conquest of the Incas in South America. Thirty to forty years later, it was widely used by the Spanish, but also common among foot soldiers of many European nationalities, including the English; the first English morions were issued during the reign of Edward VI. Low production costs aided its popularity and dissemination although officers and elite guards would have theirs elaborately engraved to display their wealth and status.

The crest or comb on the top of the helmet was designed to strengthen it. Later versions also had cheek guards and even removable faceplates to protect the soldier from sword cuts.

Spanish Conquistador Morion

The morion’s shape is derived from that of an older helmet, the Chapel de Fer, or “Kettle Hat.” Other sources suggest it was based on Moorish armor and its name is derived from Moro, the Spanish word for Moor. The New Oxford American Dictionary, however, derives it from Spanish morrión, from morro ’round object’. The Dictionary of the Spanish Language published by the Royal Spanish Academy indicates that the Spanish term for the helmet, morrión, derives from the noun morra, which means “the upper part of the head”.

In England this helmet (also known as the pikeman’s pot) is associated with the New Model Army, one of the first professional militaries. It was worn by pikemen, together with a breastplate and buff coat as they stood in phalanx-like pike and shot formations, protecting the flanks of the unarmored musketeers.

Having a short barrel doesn’t mean the pattern will be huge

Monday, May 7th, 2018

Since we were just discussing the maximum effective range of buckshot, Greg Ellifritz’s latest post, on buckshot patterning in a short-barreled shotgun, caught my attention:

I recently got my Federal paperwork back from the creation of a short-barreled shotgun. I have an old HK Benelli M-1 that I equipped with a 14″ barrel and SureFire forend. I took it out to shoot it last weekend for the first time.

With such a really short barrel, you would expect a huge pattern, right? Wrong.

Pattern is more a function of the type of choke the shotgun has than its barrel length. In fact, using buckshot loads that are not buffered or encased in a shot cup, patterns will get LARGER as the barrel length increases. The longer the barrel, the more likely that the pellets hit the inside of the barrel or each other while traveling down the barrel of the gun. Those strikes deform the each of the pellets and cause them to fly erratically, leading to a larger overall spread. Having a short barrel doesn’t mean the pattern will be huge.

Another factor of patterning size is the manufacturer of the ammunition. Not all 00 buckshot is equal. Rounds with a specialized shot cup (Federal Flight Control, Hornady TAP/Critical Defense) will shoot the tightest pattern. “Buffered” buckshot will shoot larger patterns. Unbuffered buckshot will create the largest pattern. In general, the cheaper the round, the larger and more inconsistent the pattern.

For an idea about this variability, take a look at the target below. I shot four different types of 00 Buck through the 14″ Benelli at a distance of 30 feet. There was a tremendous variation.

Buckshot Patterns from 14-Inch Cylinder Bore at 30 Feet

  • The Remington 00 Buck shot a pattern about 10″ in diameter
  • The Speer Low Recoil 00 Buck shot a pattern about 6″ in diameter
  • The Federal 00 Buck shot a pattern about 7″ in diameter
  • The Hornady TAP Magnum 00 Buck shot a pattern less than 3″ in diameter.

There is also a myth that 00 Buckshot spreads approximately one inch per yard of travel. This may be close to true with very cheap buckshot fired out of a cylinder bore. Shotguns that have a choke or rounds that use a specialty shot cup shoot groups much tighter than this standard formula suggests.

Maximum Effective Range of Buckshot

Saturday, April 28th, 2018

Watching an old police-training film, Shotgun or Sidearm?, raised some questions about shotgun patterns, and commenter ASM826, who co-blogs with Borepatch, emphasized the importance of modern pattern-controlled shells.

Brass Fetcher Ballistics tested 12 gauge shotshells — using #4, #1 and 00 buckshot (both plated and unplated) — to determine the maximum effective range of each type of shotshell when shot through a practical 12 gauge shotgun with cylinder choke.

Maximum effective range is defined here as:

  1. Having a hit probability greater than chance (greater than 50% of pellets make scoreable hits on target).
  2. Buckshot traveling fast enough to make incapacitating hit at this range (12.0” or deeper penetration in nominal 10% ballistic gelatin).

They immediately found that unplated #4 buckshot won’t reliably penetrate 12 inches of ballistic gelatin, so it is not acceptable for self-defense at any range. Plated #4 buckshot only penetrates 12 inches of ballistic gelatin out to 11 yards, so it’s not much better.

Bucketshot Velocity vs. Distance
Buckshot Velocity and Penetration
Unplated #1 buckshot penetrates 12 inches of ballistic gelatin out to 29 yards, while plated #1 is effective out to 51 yards.

At this distance, keeping most of the pellets on the target becomes an issue, as they found in their testing:

Distances between muzzle and target for the #4 buckshot and unplated #1 buckshot correspond to the maximum distance at which a single shot pellet is expected to be traveling fast enough to score an incapacitating hit. The remaining shotshells were shot at 40 yards distance.

Buckshot Hit Percentage
Buckshot Maximum Effective Range

It will be noted from above that the physical distance between the muzzle of the test shotgun and the paper targets was 40 yards for the #1 buckshot (plated, pattern-controlled), 00 buckshot (unplated, buffered) and 00 buckshot (plated, pattern-controlled.) This was to ensure that all shot pellets struck the paper and could be accounted for in the further range calculation. The 00 buckshot (unplated, buffered) load impacted the targets with greater than 50% of the shot pellets at least 50% of the time. The #1 buckshot (plated, pattern-controlled) load had a higher hit probability than the unplated 00 buckshot (maintaining a hit probability of 50+% out to 57 yards) but the individual pellets lacked the mass and initial velocity to retain terminal effectiveness beyond 51 yards. As such, the maximum effective range of this load was determined to be 51 yards. The 00 buckshot (plated, pattern-controlled) load maintains a hit probability of 50+% out to 52 yards, which is the limiting factor in maximum effective range because the individual pellets are sufficiently massive and have a high enough velocity to retain terminal effectiveness to a distance of 104 yards.

Determination of hit probability (past the 40 yard distance that was physically tested at) was based upon the average mean radius of the tested 10 shotshell/10 target test groups. Mean radius is defined as the average of the straight line distances between the Center-of-Shot-Group and each shot (USARIEM TECHNICAL NOTE TN-01/2 STATISTICAL MEASURES OF MARKSMANSHIP Richard F. Johnson Military Performance Division February 2001 U.S. Army Research Institute of Environmental Medicine) and was determined by utilizing OnTarget TDS software (OnTarget TDS).

Summary:

If your duties or circumstances lead you to carry a shotgun for self-defense when outdoors, we encourage you to make use of shotshells utilizing a pattern-controlled shotcup and copper-plated shot pellets. As tested, pattern-controlled #1 buckshot presents an interesting alternative to the more traditional 00 buckshot (also pattern-controlled) in that the maximum effective range is the same but the felt recoil is reduced by 23% over the 00 buckshot load. Since there is no difference in the long range performance of the two shells, we recommend the Federal LE132 1B load to maximize range and minimize recoil for the defensive shotgun. For self-defense indoors or in environments that physically cannot exceed 10 yards distance, we recommend #4 plated buckshot at 1250 ft/sec or higher muzzle velocity. You can maximize your shotguns effectiveness by selecting buckshot that is effective out to your maximum planned engagement distance and no further.

Shotgun or sidearm?

Saturday, April 21st, 2018

Shotgun or sidearm? This 1976 Sid Davis police training film for the Pasadena Police Department should help you decide:

Watch the first couple minutes, with the shootout and its immediate aftermath. How far away did the robber appear to be? And what kind of spread should you expect from buckshot at that range? I’m going to go out on a limb and suggest that pellets should not be hitting six feet off line at a couple dozen yards.

I was pretty surprised when they set up the scenario at the target range at “the same distance, about 50 yards.” OK, at that distance you should expect a fair amount of spread, but more like a four-foot diameter — which is still plenty dangerous on a crowded sidewalk.

The attitude toward revolvers is, well, it’s quite optimistic: “Most cops get a fair amount of practice with their sidearms, but they don’t fire a shotgun very often.” I especially liked this comment: “With his thirty-eight, Don would have hit only the suspect. One shot.” Yeah, a cop shooting a double-action revolver at 50 yards, while getting shot at, is going to hit the suspect with one shot?

Enjoy the whole thing.

It’s hardly the megawatt monster military scientists dreamed of

Wednesday, April 18th, 2018

The U.S. Navy’s most advanced laser weapon looks like a pricey amateur telescope, and, at just 30 kilowatts, it’s hardly the megawatt monster military scientists dreamed of decades ago to shoot down ICBMs, but it is a major milestone, built on a new technology:

The mission shift has been going on for years, from global defense against nuclear-armed “rogue states” to local defense against insurgents. The technology shift has been more abrupt, toward the hot new solid-state technology of optical-fiber lasers. These are the basis of a fast-growing US $2 billion industry that has reengineered the raw materials of global telecommunications to cut and weld metals, and it is now being scaled to even higher power with devastating effect.

Naval Laser by MCKIBILLO

Industrial fiber lasers can be made very powerful. IPG recently sold a 100-fiber laser to the NADEX Laser R&D Center in Japan that can weld metal parts up to 30 centimeters thick. But that high of a power output comes at the sacrifice of the ability to focus the beam over a distance. Cutting and welding tools need to operate only centimeters from their targets, after all. The highest power from single fiber lasers with beams good enough to focus onto objects hundreds of meters or more away is much less — 10 kW. Still, that’s adequate for stationary targets like unexploded ordnance left on a battlefield, because you can keep the laser trained on the explosive long enough to detonate it.

Of course, 10 kW won’t stop a speeding boat before it can deliver a bomb. The Navy laser demonstration on the USS Ponce was actually half a dozen IPG industrial fiber lasers, each rated at 5.5 kW, shot through the same telescope to form a 30-kW beam. But simply feeding the light from even more industrial fiber lasers into a bigger telescope would not produce a 100-kW beam that would retain the tight focus needed to destroy or disable fast-moving, far-off targets. The Pentagon needed a single 100-kW-class system for that. The laser would track the target’s motion, dwelling on a vulnerable spot, such as its engine or explosive payload, until the beam destroyed it.

Alas, that’s not going to happen with the existing approach. “If I could build a 100-kW laser with a single fiber, it would be great, but I can’t,” says Lockheed’s Afzal. “The scaling of a single-fiber laser to high power falls apart.” Delivering that much firepower requires new technology, he adds. The leading candidate is a way to combine the beams from many separate fiber lasers in a more controlled way than by simply firing them all through the same telescope.

There’s much, much more.

We used to own the night

Thursday, April 12th, 2018

We used to own the night, but so many night-vision devices have fallen into enemy hands that we no longer do:

Taliban fighters, many now outfitted with night vision goggles and infrared lasers, have more than doubled nighttime attacks on Afghan and U.S. troops between 2014 and 2017, according to a new report from The New York Times.

This has presented U.S. military officials with quite the conundrum: Do we give more night vision to our Afghan allies to protect themselves, even if that gear has a good chance of ending up in Taliban hands?

[...]

The Pentagon sent 210 night vision devices to the Afghan National Army 215th Corps in Helmand Province, for example, but only 161 of them were returned. While the 215th Corps attributed the discrepancy to “battle losses,” according to the Times, it’s also quite common for Afghan troops themselves to dump their own gear on the black market to make a quick buck.

“Free reminder: almost every item issued to Afghan soldiers ends up in Taliban hands,” C.J. Chivers, a Times journalist and Marine vet, wrote on Twitter. “If U.S. opts for wide issue of night-vision equipment, within months the Taliban will have even more.”

This was entirely predictable.

Let’s talk about bombs for a minute

Tuesday, March 13th, 2018

Let’s talk about bombs for a minute, Greg Ellifritz suggests:

This week, a Utah high school student was arrested after he attempted to detonate a large backpack bomb in his school. Luckily, the bomb malfunctioned and the school was evacuated before anyone was hurt.

Those of you who have taken my “Response to a Terrorist Bombing” class might remember how I discussed that in worldwide terrorist events, the trend is moving more and more towards combining bombs and guns in the attack.

If you find yourself in the middle of a mass shooting, you must be prepared for the coming bomb blasts. If you survive a bomb blast, you must be looking out for people with guns shooting up the evacuation site. That’s simply the reality of modern terrorist attacks worldwide.

This particular incident had only a bombing component (likely because it was committed by a lone high school student without any true support of a terrorist network). I predict we will see more and more of these as well.

After the Las Vegas concert shooting and the Florida school shooting, people are becoming more conscious of the potential carnage that can be inflicted by a deranged gunman armed with a semi-automatic rifle and a lot of ammunition. There are currently multiple social and political pressures being applied to limit the purchase and/or possession of these rifles. While I don’t personally think that tactic will be effective at reducing mass casualties in a terrorist attack, I believe it will become harder and harder to legally acquire semi-automatic rifles in the future.

What will the terrorist resort to if he can’t get a rifle and lots of ammo? You guessed it…bombs. Look at terrorist attacks worldwide. In countries with very strict gun control, we see terrorists use bombs more often. Bombs are easy to make and can cause massive casualties if placed in the right location at the right time. Bombs also bring a disproportionate amount of media attention, which is exactly what the killers and terrorists crave.

If you predict that semi-automatic rifles will become harder to legally acquire in the future, then you have to be prepared for more terrorist bombing incidents.

Be careful what you wish for.

Two sweeping moral visions of guns

Monday, February 19th, 2018

Ross Douthat notes that mass shootings aren’t leading to legislative action, because we have a chasm between two sweeping moral visions of guns that is too wide to be bridged by incrementalism:

The anti-gun moral vision regards America’s relationship to gun ownership as a kind of collective moral madness, a love affair with violence, a sickness unto death. Liberals increasingly write about gun ownership the way social conservatives write about abortion and euthanasia — it’s a culture of death, a Moloch devouring our children, a blood sacrifice to selfish individualism.

The pro-gun moral vision, meanwhile, links arms and the citizen, treating self-defense as an essential civic good, a means of maintaining Americans as free people rather than wards (or prisoners) of the state.

The pro-gun vision is linked, of course, to practical concerns — support for gun ownership is higher in rural areas where the police are far away. But it’s essentially a moral-political picture in which the fullness of citizenship includes the capacity to protect and defend, to step in when the state fails and resist when it imposes illegitimately.

If you asked me to defend only one of these moral pictures I would defend the pro-gun vision. I am not a gun owner but I can imagine many situations and political dispensations in which a morally responsible citizen should own a weapon; I have encountered many communities where “gun culture” seems healthy and responsible rather than a bloodthirsty cult. And the claim, often urged on anti-abortion writers like myself, that guns and abortion should both be opposed on “life” grounds seems like a category error, since every abortion kills but guns sit harmless in millions of households and many deter violence or turn back evil men.

Naturally the New York Times includes a photo of “high-capacity clips” to adorn the article. (They are regular-capacity AR magazines.)

Douthat is not a gun guy, but he takes a stab at gun regulations that would not apply to every gun owner, but instead would be imposed on the young and removed with age:

Let 18-year-olds own hunting rifles. Make revolvers available at 21. Semiautomatic pistols, at 25. And semi-automatic rifles like the AR-15 could be sold to 30-year-olds but no one younger.

Again, he’s not a gun guy, and he doesn’t seem aware that standard practice already works a bit like this, with long guns (rifles and shotguns) available at 18 and handguns at 21. The legal right to carry a handgun (concealed) generally requires a more thorough background check and a modicum of “training” — you have to sit through a class and not scare the instructor too badly when you go to shoot your gun at the range. Simply requiring paperwork seems to weed out most irresponsible people.

Of course, a system designed to keep guns away from criminals and ordinary hotheads might do very little to keep guns away from quiet loners with a nihilistic obsession.

It also sows doubt

Saturday, February 10th, 2018

Something changed in the Middle East last December, when Israel declared its first squadron of F-35s operational:

Numerically, the change seemed minor. The Israeli Air Force’s (IAF) 140 (“Golden Eagle”) Squadron has just nine F-35I Adir aircraft, scheduled to grow to fifty over the next three years. That’s a small number compared to the roughly 300 F-15s, F-15Es and F-16s currently operated by the IAF.

But the significance of Israel’s F-35s is more than numbers. First, there is the simple qualitative advantage. [...] The F-35 is superior to Iran’s collection of F-14, MiG-29s, and F-4 Phantoms, Syria’s MiG-29s and Egypt’s F-16s.

[...]

Then there is the stealth factor. It has been almost thirty-six years since Israel last conducted a major air campaign against an opponent possessing a respectable air force. Now the IAF spends its time conducting pinprick raids with a few aircraft against a Hezbollah arms convoy here, a Hamas weapons dump there. Even a handful of stealth jets will enable Israel to conduct sneak raids over Syria—or even Iran.

[...]

Israel’s F-35s add uncertainty to the mix. That Israeli aircraft could reach Iran, and routinely strike Hezbollah and Syria, is no secret. But Iran now has to wonder whether Israeli F-35s can stealthily penetrate Iranian defenses (and note that the Israeli specially modified F-35I has extra fuel capacity).

Whether or not the aircraft can successfully accomplish this doesn’t matter in this context. It’s only whether Iran believes it can, and whether this will affect Tehran’s actions.

An Israeli F-35 doesn’t just carry bombs. It also sows doubt.

Private gun ownership in Kenya

Thursday, February 1st, 2018

Alan Kasujja of the BBC World Service visited a gun range near Nairobi, Kenya to interview Anthony Wahome, chair of the [Kenyan] National Gun Owners Association and a former police officer, about private gun ownership.

Two things stood out. First, there are roughly 10,000 legally owned firearms in Kenya, versus 700,000 not-so-legally owned firearms. He points out that most of those are in the semi-arid regions, where cattle rustling is a problem. Second, he was at a shooting competition when news started coming in that the Westgate mall was under attack. They stopped the competition and decided to go to the mall to help. I was wondering why armed citizens were at the mall in shooting vests covered in IDPA patches. (The Kenyan police and military are not held in high esteem, by the way.)

Doc, how do I know where I should shoot?

Tuesday, December 26th, 2017

James Williams, M.D. was teaching a class with Mas Ayoob, when one of the students, a probation and parole officer, asked, “Doc, how do I know where I should shoot?

“It’s easy,” I replied glibly. “Go to med school, do a residency in critical care, practice in ICUs and ERs for about 20 years, and you’ll know exactly where to shoot the bad guy.”

Williams went on to design his “tactical anatomy” courses to answer that question less glibly:

Any hunter knows that to harvest a deer for your family’s winter meat you have to kill it cleanly. We train new hunters about deer anatomy, and teach them to place their bullets in the vital organs. Because if you shoot the deer any old place, it is likely to run off, wounded. It may well die, but if it is able to run a mile into the woods, its death will be a tragic waste. So we learn as hunters to stop the animal where we shoot it, by shooting it in the vital organs.

Now, lion hunters face a different problem than deer hunters. A wounded lion won’t just crawl off into the brush and die; it will turn on you and attack. In this case, the hunter’s need to stop the animal in its tracks isn’t just because he fears losing the meat; he fears losing his own life to the slashing fangs and ripping claws of a 400-pound killing machine!

The defensive shooter is more like a lion hunter than a deer hunter, because the consequences of failing to stop a violent felon are akin to those of failing to stop a charging lion. We don’t want the attacking lion or felon to stop hurting us eventually; we want him to stop hurting us now.

So if you are faced with a violent, attacking, predatory felon, how do you make sure you stop him before he can cause you grave bodily harm, or even death?

The simple answer is that you have to shoot him where it counts. And the common ideas of where it counts are often wrong.

B27 Police Qualification Target Overlaid with Anatomical Structures

To incapacitate a human being — to make him incapable of violent action — by gunshot wound (GSW) your bullets have to do serious damage to his vital organs. In my very extensive experience (and this is backed up by the medical literature, by the way) there are only two reliable ways to incapacitate a man by gunshot: either shut down the Central Nervous System (CNS, brain and high spinal cord), or shut off the supply of oxygen to the CNS.

[...]

The only two reliable target zones, then, are: first, the CNS itself, and second, the pumping system that supplies oxygen to the CNS, the heart and the plexus of Great Vessels above the heart.

Funnily enough, these are the same anatomic targets the hunter uses, whether deer or lion.

The signal was designed to exploit the difference

Sunday, December 17th, 2017

How does a Taser work?

When you pull the trigger of a Taser gun, a blast of compressed nitrogen launches its two barbed darts at 55 meters per second, less than a fifth the speed of a bullet from a typical pistol. Each projectile, which weighs 1.6 grams, has a 9-millimeter-long tip to penetrate clothing and the insulating outer layer of skin. Two whisper-thin wires trail behind for up to 9 meters, forming an electrical connection to the gun.

Because the barbs get stuck in clothing and fail to reach the skin about 30 percent of the time, the gun is designed to generate a brief arcing pulse, which ionizes the intervening air to establish a conductive path for the electricity. The arcing phase has an open-circuit peak voltage of 50,000 volts; that is, the voltage is 50 kilovolts only until the arc appears or until the barbs make contact with conductive flesh, which in the worst conditions offers around 400 ohms of resistance.

The target’s body is never exposed to the 50 kV. The X26 — the model commonly used by police departments — delivers a peak voltage of 1200 V to the body. Once the barbs establish a circuit, the gun generates a series of 100-microsecond pulses at a rate of 19 per second. Each pulse carries 100 microcoulombs of charge, so the average current is 1.9 milliamperes. To force the muscles to contract without risking electrocution, the signal was designed to exploit the difference between heart muscle and skeletal muscle.

Skeletal muscle constitutes 40 percent of a typical person’s mass and is responsible for making your biceps flex, your fingers type, and your eyelids wink. It’s organized into bundles of single-cell fibers that stretch from tendons attached to your skeleton. When your brain orders a muscle to flex, an electrical impulse shoots down a motor nerve to its termination at the midpoint of a muscle fiber. There the electrical signal changes into a chemical one, and the nerve ending sprays a molecular transmitter, acetylcholine, onto the muscle. In the milliseconds before enzymes have a chance to chew it up, some of the acetylcholine binds with receptors, called gated-ion channels, on the surface of the muscle cell. When acetylcholine sticks to them, they open, allowing the sodium ions in the surrounding salty fluid to rush in.

The movement of those ions raises the cell’s internal voltage, opening nearby ion channels that are triggered by voltage instead of by acetylcholine. As a result, a wave of voltage rolls outward along the fiber toward both ends of the muscle, moving as fast as 5 meters per second. As the voltage pulse spreads, it kick-starts the molecular machinery that contracts the muscle fiber.

By directly jolting the motor nerves with electricity, a Taser can stimulate the muscle and get the same effect.

The force with which a skeletal muscle contracts depends on the frequency at which its nerve fires. The amount of contraction elicited is proportional to the stimulation rate, up to about 70 pulses per second. At that point, called tetanus, contractions can be dangerously strong. (The same thing happens in the disease tetanus, whose primary symptom, caused by the presence of a neurotoxin, is prolonged contraction of skeletal fibers.) The Taser, with its 19 pulses per second, operates far enough from the tetanus region so that the muscles contract continuously but without causing any major damage.

Heart muscle has a somewhat different physical and electrical structure. Instead of one long cell forming a fiber that stretches from tendon to tendon, heart muscle is composed of interconnected fibers made up of many cells. The cell-to-cell connections have a low resistance, so if an electrical impulse causes one heart cell to contract, its neighbors will quickly follow suit. With the help of some specialized conduction tissue, this arrangement makes the four chambers of the heart beat in harmony and pump blood efficiently. A big jolt of current at the right frequency can turn the coordinated pump into a quivering mass of muscle. That’s just what electrocution does: the burst of electricity causes the heart’s electrical activity to become chaotic, and it stops pumping adequately — a situation known as ventricular fibrillation.

The Taser takes advantage of two natural protections against electrocution that arise from the difference between skeletal and cardiac muscle. The first — anatomy — is so obvious that it is typically overlooked. The skeletal muscles are on the outer shell of the body; the heart is nestled farther inside. In your upper body, the skeletal muscles are arranged in bands surrounding your rib cage. Because of skeletal muscle fibers’ natural inclination to conduct low-frequency electricity along their length, a larger current injected into such a muscle tends to follow the grain around the chest rather than the smaller current that penetrates toward the heart.

The second protection results from the different timing requirements of the nerves that trigger muscle contractions and the heart’s intrinsic electronics. To lock up skeletal muscle without causing ventricular fibrillation, an electronic waveform has to have a specific configuration of pulse length and current.

The key metric that electrophysiologists use to describe the relationship between the effect of pulse length and current is chronaxie, a concept similar to what we engineers call the system time constant. Electrophysiologists figure out a nerve’s chronaxie by first finding the minimal amount of current that triggers a nerve cell using a long pulse. In successive tests, the pulse is shortened. A briefer pulse of the same current is less likely to trigger the nerve, so to get the attached muscle to contract, you have to up the amperage. The chronaxie is defined as the minimum stimulus length to trigger a cell at twice the current determined from that first very long pulse. Shorten the pulse below the chronaxie and it will take more current to have any effect. So the Taser should be designed to deliver pulses of a length just short of the chronaxie of skeletal muscle nerves but far shorter than the chronaxie of heart muscle nerves.

And that’s the case. To see just how different skeletal and heart muscles are, let’s look at what it takes to seriously upset a heart’s rhythm. Basically, there are two ways: by using a relatively high average current, or by zapping it with a small number of extremely high-current pulses.

In terms of average current, the 1.9 mA mentioned earlier is about 1 percent of what’s needed to cause the heart of the typical male to fibrillate. So the Taser’s average current is far from the danger zone for healthy human hearts.

As far as single-pulse current goes, the Taser is again in the clear. The heart’s chronaxie is about 3 milliseconds — that’s 30 times as long as the chronaxie of skeletal muscle nerves and the pulse lengths of a Taser. The single-pulse current required to electrocute someone by directly pulsing the most sensitive part of the heartbeat using 3-ms pulses is about 3 A. Because a Taser’s 100-ms pulses are such a small fraction of the heart’s chronaxie, it would take significantly higher current — on the order of 90 A — to electrocute someone using a Taser.

When you factor in that the Taser barbs are likely to land in current-shunting skeletal muscle not near the heart, you wind up with a pretty large margin of safety.

The civilian version is apparently quite small — “close to a Glock 42,” according to one review.

The Stormtroopers’ normal human precision only seems inferior by comparison

Saturday, December 16th, 2017

Jonathan Jeckell busts the Stormtrooper marksmanship myth:

Clone Troopers used long rifles in their role as a mass land army during the Clone Wars, fighting engagements with the Droid Army in a variety of terrain that often called for heavy firepower and accurate long-range shots. But most Stormtroopers were issued pistols that fit their new role in short-range engagements, like fighting insurgents in cities or in the corridors onboard ships. Short weapons are handier than rifles for shock troops leading boarding parties fighting in confined spaces and also as lightweight sidearms for constabulary forces dealing with a few unruly civilians (or keeping the governor and other regional elites in line).

E-11 Blaster Rifle

The transition from rifles to pistols has a profound effect on the range and accuracy of engagements. A rifle provides a long foundation to support the weapon to control where it is pointed with many opportunities to brace it to keep it steady. A standing shooter has control of the weapon in at least three points across its length. The non-firing arm holds the end of the barrel, the butt of the weapon is planted firmly in the shooter’s armpit, and the firing hand holds the rifle in the middle. The shooter may also brace against a solid object, which substantially increases stability and the ability to accurately hold the weapon on target long enough to fire.

Pistols in contrast are held by one point (or two in the case of the long pistols used by Stormtroopers). The shooter’s body has many joints between the pistol and the ground, all of which continuously jostle despite efforts to hold them steady. The short barrel means that even the smallest movement results in larger deviations from the target as the shooter struggles with a single bracing point, trying to hold many levers (all the joints in your body) steady without jitter.

To illustrate the difference, the maximum effective range of the U.S. Army’s Beretta M9 9mm pistol is 50 meters, which means that the average person will hit 50% of the time at 50 meters. Meanwhile, the maximum effective range for the M4 Carbine is 500 meters—10 times further.

This becomes even more difficult when the shooter must react quickly and under extreme stress. Many shooters who excel on the range fail to hit what they are shooting at in combat unless they also train in realistic stressful quick-reaction scenarios. Police and the FBI maintain more useful statistics for pistol engagements because they are all studied in-depth afterwards. The FBI has found that pistol accuracy suffers when shooting in a real engagement. FBI data from 1989-1994 shows that the majority of engagements occurred within 6-10 feet (yes, feet). Less than 40% of the engagements were over 21 feet (7 meters). 60% of the engagements were within 0-21 feet, 30% from 21-45 feet, and 10% from 45-75 feet. None occurred beyond 75 feet. The average defender fires three rounds against a single assailant. The bad guys shooting at police hit their target just 14% of the time, and 95% of the police who achieve a 1st shot hit survive. This drops to 48% on the second shot. Law enforcement officers average 75-80% missed shots.

This means that Luke, Leia, and Han make some really unbelievable shots with pistols (and the scope doesn’t help). Chewbacca’s bow is held like a rifle, so his shots don’t stand out as much on the battlefield as being extraordinary. This makes the Stormtroopers’ normal human precision seem inferior in contrast. We know Luke is a Jedi, which can explain his extreme long-range accuracy with a blaster. We also know Leia has latent Force powers, which explains hers as well. Han may not be a Jedi, but he may have latent force-sensitivity despite his skepticism about the Jedi and the Force. Despite laughing off the Jedi, his piloting skill surpassed normal human capabilities like one, even though he always laughed off the Jedi.

I estimate the distance from Luke to these Stormtroopers to be at LEAST 150 meters, yet he shot two in quick succession here, then shot a foot-square door control before egressing from the fight. Leia and Han regularly made many such shots throughout the series.

The standard weapon of the Stormtroopers is the E-11 blaster rifle, which, despite its name, is rarely depicted with a stock. It was based on the British Sterling Mk IV submachine gun.

What’s odd, I pointed out to Jeckell, is that the professional soldiers aren’t decent with their primary arms, but the rebels are skilled with the Stormtroopers’ weapons. It’s clear Luke is an avid shooter (and pilot), as a country boy, but I wouldn’t expect him to be much of a pistol shot. I have no trouble imagining Han and Chewie as avid shooters, with their own weapons. I like the idea of Leia being plucky enough to get her hands dirty, but pistol-shooting is only intuitive out to five yards or so. It takes tremendous practice to master.

Supercavitating ammunition won’t skip

Friday, October 20th, 2017

DSG Technology has a new line of supercavitating ammunition, Cav-X, which won’t skip off the surface when shot into water — and which will penetrate another 60 meters, in the case of its .50-caliber round:

There is little that’s quiet about a firearm with a silencer

Wednesday, October 11th, 2017

The Washington Post is willing to print a fact-checker column noting that there is little that’s quiet about a firearm with a silencer, unless one also thinks a jackhammer is quiet:

The Environmental Protection Agency developed the noise-reduction rating (NRR), which explains how much a product might reduce noise in decibels. The decibel scale is logarithmic, rather than linear, so a difference of a few decibels is important.

Of course, different ear protection has different ratings. We found that the range for ear plugs ranged from 22 to 33 NRR, over-the-ear muffs between 22 and 31 NRR and suppressors were also in 30 NRR range, although some may go higher.

(In all likelihood, the level of noise reduction is overestimated, especially for ear plugs because tests are done in a laboratory setting and people using them often do not achieve the proper fit. 3M advises cutting the NRR by more than half to reflect this problem, so 29 NRR would translate to 11 NRR.)

Katie Peters, a spokeswoman for ARS, supplied an article that stated: “The average suppression level, according to independent tests done on a variety of commercially available suppressors, is around 30 dB, which is around the same reduction level of typical ear protection gear often used when firing guns.”

If that’s the case, we’re not sure why the group would say that ear plugs protect hearing “better” than suppressors.” It seems the answer is that they are about the same, give or take two or three decibels. And if that’s the case, ARS is especially wrong to claim that legislation to make it easier to buy such devices “does nothing to protect hearing.”

Peters acknowledged that gun enthusiasts recommend that even with suppressors, other hearing protection is necessary. Hearing damage begins to occur at about 85 decibels, about the sound of a hairdryer.

This gets us to the other issue — whether a suppressor makes it “quiet,” as Gillibrand tweeted, and harder for law enforcement officials to detect, as she and ARS suggested.

A 30-decibel reduction in theory means an AR-15 rifle would have a noise equivalent of 132 decibels. That is considered equivalent to a gunshot or a jackhammer. A .22-caliber pistol would be 116 decibels, which is louder than a 100-watt car stereo. In all likelihood, the noise level is actually higher.

Maybe we should call them mufflers?