A friend of mine asked me how guns work. We didn't have enough beer at the time for me to answer that properly.


Every subsequent tome I found was either bogged down in technical data, too specialized, too nitpicky, or too preachy (yeah, yeah, yeah, gun-grabbing hoplophobic hippies, whatever. Shut the fuck up. The woman's trying to learn here).


So, in an attempt to solve such issues, I set to the keyboard.   
 No, it's not comprehensive.
 Yes, I did leave out a lot.
 Yes, I know there's an exception to that.
 And to that.


Look, just strap in, shut up, and enjoy the ride.


  To look at guns, we start with gunpowder: one of the four basic ingredients to make what we now call a firearm. While scholars gonna argue, most agree that what we now call black powder was invented in China sometime around the 9th century. It's a mix of charcoal, sulfur, and potassium nitrate (saltpeter). Black powder is a low explosive, because it doesn't detonate with a shockwave, just burns really really fast (I guarantee you, if it happens in your face, you can't tell the difference). Don't get wrapped around the axle about it, it'll only get important in a couple centuries.


  As near as we can tell, the first of what we actually call guns started popping up in China around the 13th century, when we see references to fire-lances and fire-spears. We've also found cannon, rockets, and explosive shells from around the same time frame, there's just arguments as to when they started being used and how common they were.


  Nobody's really sure how gunpowder came to Europe. The two biggest theories are the silk road and the Mongol invasions. Whichever, the first known use of gunpowder weapons in Europe was in the 1260's, when the Spanish found themselves facing Arabs armed with what sounds like cannon and primitive grenades. By the battle of Crecy in 1346, the European nations were using cannon against each other.


  It was a matter of time before someone thought to scale down cannon into something small enough to be used by an individual, but it still held the same principle. Four main pieces: A barrel, a projectile, powder, and something to set the powder on fire. Add them together and the powder burned in the back of the barrel fast enough to transform into an expanding cloud of gas. As the gas expands, pressure builds, and the projectile is pushed out the end of the barrel towards its target. The same principle gets used today, everything else is details.
   The biggest detail is the almost universal way they're made. Human beings standing upright have their eyes higher than their hands. So almost all guns are made with sights along the top, the action (machine that makes it go bang) in the center, and the grips and trigger on the bottom. There's exceptions, but nearly all are built along these lines.


  The three details that really made handheld cannons (first handgonnes, then arquebuses and finally matchlock muskets) were the slow match, corned powder, and the serpentine. Corned powder was another way of mixing gunpowder while wet, then rolling it into corn-shaped little clumps. These dried easier than larger, round balls. The slow match was a better way of lighting the powder than using a hot wire or other method. Think a thin rope that burned about as fast as a modern stick of incense. A serpentine was the first real trigger. It's more or less just an S-hook. Secure in the middle, pull one end back, and the other goes forward. At the same time, handgonnes moved from a touch hole in the top of the barrel to one on the side, just above a pan. The pan is a small, shallow metal dish on the side. Load the gun by dumping powder down the barrel, then ramming the bullet down after it. Pour a little powder in the pan, then hook the lit end of the match to the end of the serpentine. Pulling the serpentine lowers the match, touching off the powder in the pan, which ignites the powder behind the bullet.   


  While the matchlock was cool, it had problems. Biggest issue was being worthless in any sort of rain or wet weather. You needed time to light the match before you were ready to do anything else. And sometimes the powder in the pan would ignite, but not in the chamber (ever heard of “a flash in the pan?” That's where it came from). This along with the usual risk of misfires and explosions. A couple more innovations happened, but we'll concentrate on the first two.


The wheel-lock (invented around 1500) is something I guarantee you're familiar with. If you've ever flicked a Bic, you see how a wheel-lock can work. Pulling the trigger spins a grinding wheel, which sends sparks into the pan. This solved the problems of a slow match, and somewhat alleviated the weather problems. It also made pistols something that could be practically made. But they were about as complex to make as a watch, which meant real problems if you were going to outfit an army.   


  It took a couple of false starts, but a century later (1600), Europe wound up with the flintlock. A small spring-loaded lever could be released by pulling the trigger, with a pair of jaws on the top end. A knapped flint was held between these jaws. On top of the pan was an l-shaped piece of metal called the frizzen. When the trigger was pulled, the flint scraped down the frizzen, simultaneously kicking up sparks and pushing the frizzen off the pan. Now we had the reliability of a wheel-lock, but much cheaper and easier to fix if anything went wrong.


  The flintlock's going to last us for another two centuries, so we're going to go off on a couple tangents before we get to the next evolution.


  We've mentioned pistols, but not rifles or shotguns yet. There's reasons for that.


  Shotguns were starting to evolve into what we consider their current form around this time. Navies (and pirates) were using small cannon loaded with grapeshot (a bag of small lead balls rather than one single cannonball) as an antipersonnel weapon. The blunderbuss, a small cousin of the rifle that could fire shot, was used for similar purposes. At the same time, hunters of small game thought of applying the same principle of an expanding cloud of smaller projectiles rather than a single larger one. Large smoothbore weapons designed to fire shot instead of individual bullets eventually became known as shotguns or “fowling pieces” (due to their handiness when hunting birds).


  Rifles, on the other hand, take their name for their distinctive feature, “rifling.” Rifling is a pattern of spiral grooves on the inside of the barrel. Near as most can guess, we started seeing rifling in the 15th century or so. The rifling grooves, along with a tight-fitting bullet, made for a more accurate and long-ranging shot by spinning the bullet like an American football. Rifles were great for hunters and snipers, but the tight fit of the bullet meant they took much longer to reload for a smoothbore musket. Rifles wouldn't become practical for mass production until the mid-1800's, for reasons we'll get to.


  Third mention is considering the Second Amendment to the United States Constitution (we're in the 1770's already). There's multiple points here and yes they're tangential, but they always seem to come up.


  Part one: the authors were well aware of the existence of more powerful weapons technology than already existed at the time. They were well aware of the advantages and disadvantages of rifles vs. muskets, among other technological differences. Repeating firearms, while rare, did exist: the Puckle Gun, a crank-operated flintlock ancestor of the machine gun was patented in 1717, though never saw much use. The Kalthoff repeater, invented in the 1600's, was a multi-shot rifle. A crude lever-action system dropped a new load of powder into the chamber, then a ball, then cocked itself. Much like the wheel-lock, the cost and mechanical complexity of the parts kept it from being widely used, though it was known about. Various kinds of early revolvers were made as far back as matchlock days.


  Part two: the phrase “well-regulated” in the mid-to-late 1700's was generally defined as “in good working order,” or “held to a common standard.” One of the massive headaches of the continental army was the fact that most of the army and all of the militia were armed with personally owned weapons: everything from run-of-the-mill muskets to Kentucky rifles to grandpa's fowling piece. Washington's quartermaster general at one point complained that there were entire companies in the army where the only ammunition that fit more than one weapon was the powder. Which made resupply a stone bitch. Add to that the concept of “militia” as “everyone able-bodied man between puberty and senility not already in the military.” Militia members could come and go as they pleased, and were only under discipline when they were actually with their unit.


Taking all of that into account, the phrase “well-regulated militia” today would mean “every adult civilian who can use a personal weapon.” Ideally, personal weapons that can use the same ammunition used by the military. Which today would be 9mm parabellum pistols, .223/5.56 rifles, and 12ga shotguns. By astonishing coincidence, those are some of the most popular calibers of their respective platforms.


  Back to history.


  The 1800's gave us a lot of changes. I'm going to go through them in roughly chronological order, so we'll get a sense at which came after what.      


  First up is the percussion cap. A Scottish preacher who liked hunting had a problem with the lock family of guns: the unique double blast caused by the pan and then the chamber igniting gave game birds a chance to escape before his shotgun fired (it sounds more like “ka-POW!” than the “crack!” you hear with modern firearms). What began as a scent-bottle full of explosives dripped into the chamber turned into a metal cap about the size of the eraser end of a pencil. This cap contained an explosive compound and fitted over a metal nipple that led directly to the chamber. Instead of a flint, a metal hammer came down with a pull of the trigger, causing the cap to shoot sparks through the nipple and into the chamber. As a bonus, some more (but not all) of the issues with wet weather cleared up. It was also relatively easy to convert flintlocks into percussion locks, which allowed entire arsenals to be converted.


  Next is what we think of as a modern revolver. While I've pointed out that versions existed for a while, the ratchet-and-pawl mechanism we see on revolvers today was patented and popularized by Samuel Colt in the late 1830's. These early revolvers used percussion cap mechanisms, with each chamber in the cylinder having it's own cap, powder measure, and bullet loaded separately (also called “cap-and-ball” revolvers).


  After that is the minie ball. Remember the musket vs rifle issues I mentioned before? The Minie ball had greased grooves on the sides and a hollowed-out bottom, like the bottom of a beer can or peanut butter jar. When fired, the force of the gas cloud caused the back of the ball to expand, causing it to hug the walls of the barrel and spin with the rifling. Now we had the accuracy of rifles with the loading time of muskets.


  Next is the integrated cartridge. This is what we think a modern bullet or “round” consists of today: casing, powder, primer, and bullet all in one piece, rather than applied individually to the weapon. They didn't become particularly popular until after the American Civil War. With the integrated cartridge, all the mess and weather problems went away, and now the mechanism of a gun (called the action) centered on a way to hit the primer of a cartridge with a firing pin, then get rid of the old casing (bullet having gone on to it's target while the powder and primer burned away) and put a fresh cartridge into the chamber. This meant we started to see bolt-action (working a bolt with a handle up and back and forth, like the latch on a gate) lever-action (moving a lever under the trigger back and forth) and pump-action (racking a slide on a tube back and forth under the barrel), among others.


  I'm going to make a side note about actions on pistols in case it gets confusing later:


  Early revolvers were all made in single-action, but weren't called that until other actions were invented around now. Single-action means pulling the trigger does a single thing: dropping the hammer on the loaded chamber. Cocking the pistol by pulling the hammer back is a separate action entirely. The invention of repeating rifles meant that, say, a lever-action rifle would eject the spent case, load the next cartridge, and cock the hammer back, leaving a trigger pull all that needs to be done.


This led to modifying revolvers into “double-action,” which meant that you could either cock the hammer manually and then pull the trigger, just like a single action. Or, you could simply pull the trigger (longer and harder), which would cock the hammer back and let it fall as well.  


Some revolvers are called “double action only,” where the hammer is hidden inside the receiver and can't be cocked manually (usually smaller, concealed revolvers, to prevent the hammer from snagging on clothing when drawn).   


  Now we're well and truly in the time of the wild west. But there's a few more inventions before we leave the 1800's.


  First is the machine gun. While there were efforts to make weapons capable of rapidly sending a lot of rounds downrange, they were still operated by hand-cranking. The first true machine gun, where the energy produced by the recoil of one round was used to eject the case, feed the next round, and cock the weapon, was put together by Hiram Maxim in the 1880's.


With the machine gun a reality, attempts to replicate the design on a smaller scale came almost immediately. While more difficult to make than fully automatic designs, semiautomatic (or autoloading) pistols and rifles started cropping up within a few years.


  The last invention of the 1800's to make a big impact was smokeless powder. Derived from nitrocellulose rather than the old black powder formula, smokeless powder had three big advantages: it burned cooler than black powder, it left a lot less residue (making cleaning much less of a priority), and it burned several times faster (allowing for much more power in much smaller packages).


Quick side note about caliber and gauge.


  Caliber in a firearms sense is ideally just describing the size of the cartridge. But with multiple manufacturers spread across the world with no universally applied standard, it gets to be a bit of a sketchy descriptive term. Take 9mm for example. There's over a dozen common calibers I know about that are technically 9mm in diameter across the base of the bullet. The most common is 9x19mm Luger (the name of the initial manufacturer) also called 9mm Parabellum (a marketing name, from the Latin “Sic vis pacem para bellum.” “If you would make peace, prepare for war.”). Across the pond, caliber is measured in decimals of an inch instead of the metric system. Then there's the gauge measurement of shotguns, which is determined by how many spheres the same diameter of the bore would equal a pound of lead. That's why a 10ga shotgun is bigger than a 12 ga, and so on down the line.


  There's a ton of little inconsistencies spread across two centuries of manufacturers. So long as you're using the right ammunition in the right weapon, it really isn't an issue.   


  Now we've entered the 20th century, with a lot of recognizable weaponry. But there's a good bit of innovation happening still.


The first one being World War One, where the need for a new personal weapon cropped up. A soldier's main weapon then, as now, is a rifle. Designed to reach out and touch someone at over a hundred meters, with normally a modified hunting round (if it can kill a deer, it can kill a horse, and it can definitely kill a rider). But in the trenches of Europe, rifles were hard to maneuver (especially with bayonets). Carbines (a shortened rifle originally designed for cavalry to use on horseback) were in short supply, as were pistols. The Germans had some experiments with hooking up carbine stocks and extended magazines to pistols.  

  The solution was the submachine gun: smaller than a carbine, the ammunition of a pistol, and the full-auto capability of a machine gun. Though designed for WWI, it never saw actual use there (some prototype Thompsons were being shipped to Europe when the war ended). The Thompson was however used a great deal in WWII, as well as both by cops and gangsters during Prohibition.   


  The next big change is the source of a lot of arguments, so keep that in mind. Specifically, the development of the assault rifle. (That's assault rifle, not assault weapon. “Assault weapon” is a made up bullshit term that effectively means “scary black guns.” Just so we're clear).


  By WWII, armies were still using what we'll call “battle rifles”: long bodies, big bullets, fed by shoving individual rounds into an internal magazine or using a stripper clip shoved into the action. Effective when you have a lot of space, but can get cramped in close quarters like cities, where submachine guns were devastatingly effective. Finding a happy medium between the two was key
 

The first design was actually German: the STG-44 “Sturmgewher,” which is where we get the term “assault rifle.” A lot of its features, like a detachable box magazine for ammo, a shorter overall length, select-fire (capable of full-auto or semiautomatic fire) and smaller but still powerful round, would pop up in future weapons.


  The next to be built was the Automatic Rifle, Kalashnikov, 1947, or AK-47. Mikhail Kalashnikov was a self-taught machinist who was wounded early in WWII. During his hospital stay, he overheard other soldiers griping about the Germans having better gear. He designed a submachine gun before leaving the hospital, which wasn't adopted, but did earn him a transfer from tanks to weapons development.


  Kalashnikov designed the rifle around what the Russian soldier had: recruitment (poor peasant cannon fodder), training (shitty), maintenance (nonexistent), and supply lines (diverted or stolen, assuming they existed in the first place). The receiver is a piece of sheet metal bent over twice with some holes drilled in it. The piston and action have loose tolerances and a lot of empty space inside. It fires a cut-down medium machine gun round.


The end result was a rifle that couldn't be arsed to hit the broad side of a barn beyond 300 meters. But that didn't matter, as the few Soviet conscripts that could would be taken off the lines and trained as snipers anyway. The loose tolerances and empty space meant that any manner of dirt and debris could get into the weapon without keeping it from firing. The selector switch goes (in order) from “safe' to “full auto” to “single shot,” ostensibly to prevent panicking conscripts from cranking the switch down and turning their weapons instantly to full auto when the first shot was fired, thence to spray and pray. It works, assuming the switch is ever used in the first place. In other words, it was designed for peasant conscripts who would have no training and never see so much as a cleaning brush or a spare part. It's been popular around the world with communist armies, insurgencies, drug lords, gangsters, and child soldiers ever since.


  Back in the U.S., the Army was trying to make a similar weapon, replacing the battle rifle, automatic rifle, and submachine gun. A gunsmith named Eugene Stoner came up with a rifle that used tight tolerances and a small round backed into a large casing. (A smaller bullet than the AK, but one that had twice the range and enough power to still stop a human target. It was also lighter, allowing a soldier to carry more ammo than his Russian counterpart. Oddly enough, both rifles standardized 30-round box magazines early on).   


  The result was the AR-15 platform, known to the military as the M16. That said, there were some growing pains with the platform. Early version were sent to Vietnam and used by SEALS, who praised the performance of the weapon. Then over a million were issued to the Army, where it grew a lousy reputation.


The reason for the discrepancy is simple: the tight tolerances mean the AR needs regular maintenance and cleaning. The S.E.A.L.'s, who treat weapons maintenance in a fashion that can only be called “cult-like,” had no problems. Then some idiot in supply read the specs, saw that a single part (the gas tube) was described as “self-cleaning.” The Army then sent 1 million of them to Southeast Asia. Without cleaning gear.


  The AR platform had a couple of tweaks to the design over the years. But the basic design has remained the same. To make a long story short: the AK was designed for amateurs, the AR was designed for professionals. Nowadays the appeal of the platform is more around it's modular nature. By releasing two pins, the weapon comes in half. Put a new upper on, and you're shooting a different caliber. The same weapon, with minimal changes, can be used to hunt, target shoot, or defend one's home. An adjustable stock lets 6'7” 300lb me comfortably shoot the same gun as my 4'10” fun size friend. Police, the military, and civilians have been finding it useful for over 60 years now. About the only people that haven't found it useful are criminals (it's rarely used in crime of any sort, but that's true of rifles as a whole, not just the AR platform).   


  Ending our time in the 20th century is the invention of the striker. While a handgun's hammer is spring-loaded, going back and forth in an arc to drop the firing pin on the primer, a striker is spring-loaded to go directly forward and back. They were first made popular by the Glock line of pistols in the 1980's, but other manufacturers have come up with their own over the years.


  The AR platform is over half a century old. The M1911, one of the most popular pistols in existence, is over a century old. The Browning M2 .50 machine gun (or the “Ma Deuce”) was invented before my Grandfather was born. He and I both went to war with it, 60 years apart. It's still in service today.   


  Currently, we're not seeing changes in design so much as we are in materials. Some duck hunters are using steel shot instead of lead for environmental reasons. Primers have shifted from using mercury fulminate to lead styphate in some cases. Polymer receivers are reducing weight but keeping strength. And 3D printing is ensuring that home gunsmithing will still be possible as it's ever been.   


  So that's a brief history of guns. Hope you enjoyed the ride, looking forward to the future.

Oversimplification makes you stupid. Or at least unaware.
That's why one of the things seriously holding a lot of social justice movements back is the inability (or unwillingness) to distinguish between individual acts in favor of lumping them all together and blaming large, easy targets.
Case in point, police shootings. There's about three broad types of them. Which only helps us so much because they can and do overlap on the edges. But lumping them all together hurts far more than it helps.
In order of likelihood, they are...

Legitimate shootings
These happen a few hundred times a year. You never hear about most of them, because most of them are not only legitimate, but fairly obviously legitimate. In the case of Rodrigo Guardiola, he ran from a DUI checkpoint, crashed into a patrol car, ran on foot, fought a state trooper hand-to-hand for over a minute, then attempted to drown the trooper in a creek. The trooper shot and killed him.
Contrary to popular belief, even police officers need more than a Jimbo on South Park "They're coming right for us!" excuse. While it varies slightly from state to state, in general terms, an officer needs to face three things in a suspect before using lethal force:
Ability: The ability to cause death or grievous bodily harm in another person.
This is usually described as a weapon, but any sort of serious physical disparity will do: size difference, male vs female, young vs elderly, able vs disabled, ect. If it's fairly obvious "who would win/cause some serious damage in a fight" there's the ability.
Opportunity: The opportunity to inflict death or great harm on another person.
The ability doesn't mean much if they're not there to exercise it. Someone standing on the next subway platform couldn't touch you without a firearm, ergo, they don't currently have the opportunity.
Jeopardy: Demonstrating an immediate ~intent~ to inflict death or grievous bodily harm in another person.
That's the last part of the trinity: the intent. Yeah, someone my size can put the hurt on most folks. But an officer (or civilian) isn't justified in shooting me if I'm just standing next to them, Facebooking on my phone.
ALL THREE ELEMENTS NEED TO BE THERE!
Of the three, Jeopardy is the most subjective and the most debated about. The key to remember is what a reasonable person would think AT THE TIME. Human beings aren't mind readers, and the courts recognize that. Someone who does use lethal force has to be able to articulate reasonably that all three were present as they saw it.
Of course, where Jeopardy really gets argued about is that everyone has an asshole/opinion about what constitutes it.
I'm 6'7", can palm a basketball, and have made a living off of my potential for violence in the past. If I'm within speaking distance of someone, I have ability and opportunity. Which means my behavior and the interpretation of it by people around me determine whether or not I put them in jeopardy.
This is why I'm soft-spoken and wear silly tshirts and have a stuffed animal tattoo, folks. It's not that I'm incapable of anger. I was just born looking like a second-tier villain and I'm trying not to get shot. I'm told it sucks.
Back to police shootings:
Ability to do so, close enough to do so now, looked like they were attempting to do so.
Those three steps are what determines whether an officer will or will not shoot.
On top of that is what's called a use of force pyramid. I'm simplifying this to keep from writing a novel, but long story short: the guideline is to use one step higher of force than what the suspect is using OR IS ABOUT TO USE in order to ensure compliance. What that means is, ideally a cop stays one step higher on the force pyramid than their suspect. However, it's more of a dial than a ladder. When a suspect suddenly flips the dial all the way over to "lethal," the officer not only needs to do so as well, but needs to get to that end of the dial first to keep themselves and innocent bystanders alive.
The problem with lumping legitimate shoots in with police brutality is that you wind up punishing officers (and those who came after them) who did nothing wrong.
Let me repeat that again.
PUNISHING PEOPLE WHO DID NOTHING WRONG!
It's really easy to armchair quarterback and say, "oh, he shot someone and now gets a paid vacation."
He gets a vacation because the department does in fact have to determine whether or not the shoot was legit. If it was (and the vast majority of the time it is), they need to send him back out into the streets again. If not, then he needs to be off the streets and stay off from the word go.
Do you know anyone who would go back out if they had to face a full-blown trial with the possibility of conviction every single time? I don't.
"But can't they {insert alternative here}?"
Maybe. Every shooting is different. and the Navy SEAL phrase "situation dictates" applies to every situation. Again, the unholy trinity and use of force pyramid applies.
But I'll remind you now, the trinity mentioned above describes the officer and/or innocent bystanders being in immediate danger of death or grievous bodily harm.
Respond too late to a threat like that and you wind up like Deputy Dinkheller.
In 1999, Dinkheller pulled over a mentally disturbed old man. The man ignored commands, screamed threats, danced around, and in general acted like an asshole. Until he drew a rifle from the back of his truck and shot Dinkheller repeatedly. Dinkheller managed to wound the old man, but not before being mortally wounded himself.
The entire incident was caught on camera. You can hear Dinkheller's dying screams very clearly.
What most don't know is that Dinkheller had recently been chewed out by a superior for being too quick to draw his weapon in an earlier incident. Thus his hesitation despite seeing all three pieces of the above mentioned trinity. He hesitated and he died in agony.
The line is decidedly fine. Waiting too long, as shown, gets you killed.
Reacting too fast, on the other hand, leads into our second category.

Tragic fuckups
This is the category you're most likely to see televised because, by its nature, the circumstances surrounding a shooting are subjective. It's not a case of justified or otherwise, it's on a continuum of who's at fault in particular.
The vast majority of this, again, revolves around Jeopardy. Did the suspect reach for a gun? Or did they reach for a wallet? Both are commonly carried behind the back. And how fast do you reach for a wallet when asked for ID?
In some cases, the question revolves around, "was the trinity established? Or did the officer get a 'man with a gun' call and open fire before they could tell whether or not the trinity was in place?" The answer to that question is the difference between a legitimate shoot and a tragic fuckup that's punishable or even criminally liable.
In some cases, the fuckup is neither in the officer nor in the suspect, but in the institution. If there's no shoot/don't shoot training available (and in too many departments, there isn't) and an officer shoots someone reaching for a wallet, do we apply the trinity? Prosecute the officer? Or censure the department?
(It will boggle the mind of most of America how little firearms training is mandated by most police forces. And a lot of it boils down to department budgets. Do you want more officers? Do you want them to have body armor and body cameras? Do you want them to have shoot/don't shoot training? Pick one. Two, in a good year.
This also brings up officer quality. If there's no budget in a rural area, then yes, a cheif can and will hire cousins to work for cheap. Losing a single officer means either waiting a year for a candidate to come through the academy, or hiring from another department, who may be glad to see the back of an officer who's now your problem.)
And in some cases it's a fuckup combo.
Take the Eric Gardner case. In NYC, cigarettes are heavily taxed. Hence the ancient custom of bootlegging. Buying cartons and cases in another state, going back to the city and selling them at a discount. Shop owners, who are paying these onerous taxes, see folks selling untaxed ones outside their shops and see the money flying out of their pocket. So they complain to the mayor, who complains to the chief. Who comes down on high and removes officer discretion. Word is: if they're selling loosies, they're being arrested.
There's Eric, selling as usual. Cops roll up, arrest him. He resists. One makes the clumsiest, most ineffective choke hold I'd ever seen before backup helps him cuff the man. He dies in the ambulance on the way to the hospital.
So let's count the fuckups: one department removing officer discretion, one officer who can't apply a proper hold, and one suspect who resists arrest knowing how aerobic an activity that is and what a laundry list of medical problems he's got. How do you cut the slices of the fuckup pie?
And some fuckups you can only see if you look into the human heart. When Johannes Mehserle shot and killed Oscar Grant, was it a tragic fuckup committed by an undertrained, hopped-up-on-adrenaline cop? Or was it our third category?

Outright murders
These I almost never see in the context of police shootings as we know them now. Premeditated murder by officers usually happens off the clock (as in the assassination of Derwin Brown).
Some are currently awaiting trial, and could be regarded as either an outright murder or a tragic fuckup. Cases like the Walter Scott shooting are particularly notable, as witness video has already caught the officer there in one lie. The trial is set for October. October is also when the trial of the officer who shot Samuel DuBose in Ohio is set to begin.

The problems with lumping them together
This has already gotten longer than i'd like, but you can already see where I'm going with the breadth of the problem.
When you refer to every publicized police shooting as a murder, your credibility dies.
Pointing something out as a tragic fuckup means nothing unless you look deeper and find out who fucked up and how badly.
This isn't helped by a 24/7 news cycle that only knows that seeing people bleed pisses people off, and pissed off people bring clicks.
All of this is on top of the really bad unintended consequences of those who claim they seek justice when what they really want is vengeance.
By the same token, we need to realize what a nuanced skill is really needed in order to shoot only when necessary, while ~still~ using the force needed to defend officers and innocents alike. Ways to implement and maintain that skill needs to happen. Above all, education needs to happen to show beyond the blood.