Why are police issued machine guns?

It’s quite common for police departments in many nations to have multiple fully automatic* M-16, FAL, and MP5 firearms, which are apparently often carried in squad cars. I’ve even seen pictures of American SWAT teams with .50 and .30 caliber heavy machine guns mounted on their vehicles. What’s the reasoning behind using these in lieu of semi-automatic** weapons? Adding dozens or hundreds of additional rounds to those already flying about in an urban gunfight sounds like an excellent recipe for heavy collateral damage and innocent bystanders being shot.
*When the trigger is held down, the weapon fires until all rounds are expended
**One shot is fired for every trigger pull

Most police departments use force in graduated steps. I don’t know of any in the US that routinely patrol with more than sidearms and shotguns. You always want to have superior firepower, though, and in those cases where you have several heavily-armed suspects, or one armed with a piece of military hardware, you have to reach higher on the rack for something that gives you the edge. In extreme cases, paramilitary forces may attempt a major robbery or similar crime and you need police with advanced training and yet-heavier weapons.

I think that the presence of such forces, on ready call, are as much of a deterrent as an elevated response option. It’s like old-time bank robbers who would hit the towns with one elderly sheriff, and avoid those with well-equipped constabulatories. Planning a heavy bank robbery takes more cojones if you know you could come out into trained snipers and automatic weapons.

Cite on it being “quite common” for police officers to be issued fully automatic weapons? I doubt very much that’s true.

And the North Hollywood Shootout is commonly pointed to as the reason police agencies have escalated their weaponry.

I was on a BART train (SF Bay Area’s light rail system) once that got stopped a station for a quick run-through by cops who were looking for someone. One of the cops (not sure if it was BART police or local police) had a belt-fed machine gun with the belt lapped around his neck like a bandolier. Utterly baffling.

Though I generally agree with this statement, I have seen what looks like AR-15s to be allowed as routine patrol weapons instead of shotguns.

You are mistaken, at least for the US. Police agencies do have nasty looking black ‘assault rifles’, but they are semi-automatic, one trigger pull, one shot. Not much different than what the civilians can buy.

I’d be real interested to see these pictures of SWAT vehicles with mounted .50s on them as well.

Eh, I’d prefer they carry some form of rifle in lieu of a shotgun. On occasion they might face attackers at longer distances, and when using buckshot there’s the risk that the multiple spreading pellets will not all hit the target, leading to more stray rounds in an urban environment.

The DoD gives police agencies large quantities of surplus military weaponry. There’s currently a bit of a scandal concerning the number that have been lost or stolen.
http://www.journalgazette.net/article/20090906/LOCAL07/309069910
http://californiawatch.org/public-safety/free-military-surplus-gear-boon-local-calif-law-enforcement-15493
http://www.daytondailynews.com/news/news/local/local-police-boost-arsenals-with-free-military-wea/nPSGC/
http://www.sacbee.com/2012/06/19/4575339/feds-want-inventory-of-free-military.html

M16s can be loaned to them by the Federal Government, which saves the department the cost of buying them.

Depends on the police department. A friend of mine is a cop, we were at a wedding party where a couple of highly educated guests locked their newborn in the car. The police came to handle the emergency (I don’t know why, I could have taken care of it with a coat hanger). My friend was highly impressed with the Attleboro MA police cars and all the electronics they had. They had a video connection to headquarters, internet access, all the bells and whistles. They asked my friend what he had in his car. He said “Automatic weapons”. He works in meth country. Just depends on the needs.

Courtesy of South Carolina. Can’t tell the caliber from the image, but it’s obviously a belt-fed HMG.
http://cache.gizmodo.com/assets/images/12/2008/09/Put-Down-The-TV.jpg

Well there’s Sheriff Arpaio using Steven Segal in a tank to raid a chicken coop so as to free the chickens, or euthanize them as may be. You can’t make this shit up.

In the Uk i think they only coppers who openly machine guns are at airports…i guess they might need to kill a lot of people quickly.

“Capable” of automatic weapons fire does not mean they are automatic. Most civilian semi-auto weapons are ‘capable of’ being converted to full auto, with a few modifications.

Your cites show nothing to support your claims that civilian police departments have full auto guns. Indead they say the oposite.

Yes, police departments can buy used government guns. No they don’t just get the full auto versions. Full auto is very tightly regulated and the average police department does not qualify. Full auto could not even be licenced to a ‘department’ but must be registered to the individual.

There may be exceptions for agencies such as the BATF, FBI and Secret Service, as departments. But not for the individuals.

I am bowing out of this latest anti-gun screed. Your OP leads me to believe that you are yet another non-US person posting from ignorance.

The typical cop here in the US carries a pistol. They might have a backup pistol concealed in a pant leg. If they need it, they may have shotguns or semi-automatic rifles (e.g. an AR-15) in the trunk of their car, but I don’t often see them with them out.

Cops are supposed to use as much force as necessary. Cops don’t normally pull out their weapons when making a traffic stop - they are stopping you for a minor matter and they have no indication that you will attempt to fight back or otherwise resist. If they are coming for you and have good reason to believe that you might resist (e.g. you are wanted for a violent crime or one potentially carrying a long prison term), they may approach with weapons drawn.

Occasionally you will see cops on patrol or guard duty at important facilities or at major events holding rifles or shotguns at the ready, but I doubt they actually have their hands on the trigger because that would be too dangerous.

Hey there Tex, don’t go away mad. I’m sure that whatever that big gun on the tank was, it wasn’t automatic.

That’s a .50cal.

In case they run into a giant ant.

We should all be able to buy full auto weapons…what’s the big deal.

M16s are “capable” of full auto fire, in the sense that they are selectable to safe, semi-auto, or full auto (or 3 rd burst for newer models). I think his cites are just fine for his claims.

Better to have them and not need them, than need them and not have them.