US Police vs. UK Police ???


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David
July 21, 2005, 10:11 PM
I have noticed, that in GENERAL, US Police on duty with long-guns tend to hold them with the gun's muzzle towards the ground, while the UK Police tend to hold their long-guns with the muzzle towards the sky (see photos below as examples).

Why?

What are the pros and cons of each type of carry, if any?

:confused: :scrutiny: :confused:

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Standing Wolf
July 21, 2005, 10:45 PM
That which goes up will come down somewhere—one generally has no idea where—at nearly the speed at which it began its ascent. That which goes down can be directed safely.

Oleg Volk
July 21, 2005, 10:52 PM
British use may be stemming from the more ceremonial nature of their interactions with guns.

feedthehogs
July 21, 2005, 10:56 PM
Some of the police pics I've seen recently out of the UK show a different style than what I remember.
Black dress, shaved heads and subs strapped on.

Jim K
July 22, 2005, 12:28 AM
Having been in the UK on several occasions when police used guns, I would be very afraid to walk around London today, and my fear would not be of terrorist bombings. In the cases I knew of, the British police, when issued firearms, just went berserk, tending to shoot at anything that moved. They seemed so unfamiliar with guns and so trigger happy that accidental shootings seemed to be part of any situation where armed police were employed. Of course, under the British system, the press reported only a few bare facts, then was told to go cover a royal scandal or something and forget the killings by police.

Jim

carebear
July 22, 2005, 01:03 AM
Well just in the pictures shown, it's apples and oranges and demonstrates mindset and training.

The US cop is at a low ready, the Brits are at parade ground port arms.

entropy
July 22, 2005, 01:19 PM
I'll bet the SAS carries them at low ready. The two bobbies there are for show, to make the Brits feels more comfortable, and to show that Her Majesty cares about her subjects .

Chipperman
July 22, 2005, 01:47 PM
If you look at the Brit pic, you can see that neither of them would be able to deploy the weapon with any degree of speed. The guy on the left isn't even holding the pistol grip. The guy on the right has the stock over his forearm. :rolleyes:

dasmi
July 22, 2005, 01:51 PM
The UK cops look like decoration, the US cop looks like he's ready to get down and dirty.

Eightball
July 22, 2005, 02:00 PM
If you look at the Brit pic, you can see that neither of them would be able to deploy the weapon with any degree of speed. The guy on the left isn't even holding the pistol grip. The guy on the right has the stock over his forearm.I was going to point that out, but it looks like you beat me to the punch. But it bears to be repeated again. Who knows, maybe the Brits are too fascinated by what they're holding (what IS this thing, and how is it useful to us, trained police officers? :rolleyes: ) to know how to keep them at the ready? :scrutiny:

dasmi
July 22, 2005, 02:04 PM
Heh, the guy on the left looks rather proud of himself :)

Iain
July 22, 2005, 02:19 PM
You don't think armed British police are highly trained?

entropy
July 22, 2005, 02:21 PM
Not those two. Or else they're not serious about the duty.

The guy on the left has that 'patience, my butt....I'm going to kill something' look. :what:

jdkelly
July 22, 2005, 02:38 PM
...—at nearly the speed at which it began its ascent.---Standing Wolf

Are you sure?



Respectfully,

jdkelly

CAS700850
July 22, 2005, 02:55 PM
Our SWAT guys train muzzle-down, and use muzzle down for both carry on a sling and low-ready. When I asked about it, I got two reasons. First was that they claim to have more controland speed from the ready position if it is muzzle down. I don't know if this is accurate or not. the second was that in the highly unlikely event of an AD during an entry or raid, compare the possible inuries. Muzzle up=injury to head or chest of team member. Muzzle down= injury to foot or leg.

One of the guys then confided that with the gear and slings they use, muzzle down was more comfortable and faster "on the draw" so to speak.

dasmi
July 22, 2005, 02:56 PM
Try holding a gun muzzle up, and bring it down on target without dropping too low first, and having to come back up.
Next, try holding a gun muzzle down, and try to bring it up on target.

firefighter4884
July 22, 2005, 03:57 PM
jdkelly

if you analyze velocies and stuff from physics, then yes it is true. The descending projectile will have the same velocity when it hits the ground as it did when it left the muzzle.

However, there is a parasitic drag on the round from the air as the bullet flies. The question is how much affect does the drag have on the round? It's actually an incredibly complex question...

--Jim

Yes, I'm an engineer. :)

armoredman
July 22, 2005, 05:05 PM
The guy on the left is holding the MP5 like an Enfield....

David
July 22, 2005, 05:14 PM
Another "odd" photo of UK Police holding their long-arms.

:what: :uhoh: :what:

P95Carry
July 22, 2005, 05:21 PM
Hey Jim - good to see you here. Does not tho the projectile only achieve terminal velocity on down trip? 120mph tops.... which is 176 fps. It only has acceleration due to gravity, 32 ft/sec^2. For a 9mm 115 grain this would give approx 8 ft lbs.

I am an engineer too - but an old and rusty one :D

Control Group
July 22, 2005, 05:25 PM
However, there is a parasitic drag on the round from the air as the bullet flies. The question is how much affect does the drag have on the round? It's actually an incredibly complex question...
But doesn't atmospheric drag act on the round both on the way up and on the way down? That is, won't it amount to two vectors of (pretty much) equal magnitude but opposite direction? I pose this as an actual question, not an argument. This is something I've wondered about for quite a while.

(As you may have surmised, I'm an armchair physicist at best; the math required to actually do physics is beyond me)

Control Group
July 22, 2005, 05:33 PM
P95Carry:

Again, I'm no expert...but that figure rings a bell as the terminal velocity of a skydiver with a closed parachute. I'm fairly sure (but not certain) that terminal velocity in general depends on the coefficient of drag, which is a function of cross section and mass, so I'd assume that a bullet's terminal velocity would be significantly higher than a skydiver's.

But I could be full of it, too.

petrel800
July 22, 2005, 05:33 PM
The bullet will acheive a terminal velocity, and if I recall properly, will have a higher coefficient of drag due to the fact the round will tend to fall bottom first.

The round will still have enough energy to injure or kill someone, as a lady at the Peach Bowl found out when a stray 9mm round pierced the roof and landed in her leg. This was of course the result of someone firing celebratory gun fire into the air on New Years Eve.

P95Carry
July 22, 2005, 05:35 PM
If simplified to a true vertical up trip - then the muzzle velocity will decay over time due to drag and the antagonistic acceleration due to gravity.

Once max altitude reached then only gravity acceleration remains to influence the projectile downward. That will impose itself but air drag will limit the speed (in theory) to the terminal velocity. Take away drag and speed would increase as inverse square law IIRC.

P95Carry
July 22, 2005, 05:40 PM
CG - remember I am rusty! Sure drag coefficient will matter - but of course remember too the old experiment - in a vacuum a feather falls at same speed as a ball bearing. That is when drag taken out of the system.

I know skydivers can I believe push speed from supposed terminal to well over by going into an ''airodynamic'' shape.

However per the original from firefighter - I can think of no way that ''g'' can accelerate a downward travelling projectile to achieve anything like original MV - which we might assume to be from a carbine 9mm - something like 1200 and more fps.

UberPhLuBB
July 22, 2005, 05:41 PM
"I say, does my machine-pistol say 'replica' on the side? I seem to be getting funny looks from the passersby, what what."

"It most certainly does, and I hope we are not required to do more than keep these off the ground. I don't suppose they told you how to hold one of these and look intimidating? I feel like a bloody fop."

http://home.earthlink.net/~uberphlubb/ukpolicerifle1a.jpg

Control Group
July 22, 2005, 06:06 PM
However per the original from firefighter - I can think of no way that ''g'' can accelerate a downward travelling projectile to achieve anything like original MV - which we might assume to be from a carbine 9mm - something like 1200 and more fps
Hrm

I hadn't thought about it that way, though of course I should have. You're right: once the bullet has reached its maximum altitude, the only things we have to worry about are wind resistance and g. So, using 1200 fps (both because I trust your estimate on speed, and because that's not much past Mach 1, and I know wind resistance dynamics change drastically at Mach 1), for the round to accelerate to that speed due to g, even ignoring drag, it would have to be falling for 37.5 seconds (unless my math is off, of course). This seems like a really long time, to me.

By the same token, if it started out at 1200 fps, it would take 37.5 seconds for gravity to bring it to a halt, too. It won't take that long in atmosphere, of course, because drag will add to gravity's 9.8N (with apologies for mixing SI and English units). On the way back down, then, it won't have to fall as far, which also means it doesn't have as long to accelerate, so you must be right - it can't possibly land with the same velocity it had going up.

And, in a Eureka moment, I just understood why. On the way up, you've got three forces: the initial acceleration (up), wind resistance (down), and gravity (down). On the way down, you've got two forces: wind resistance (up), and gravity (down). Given that gravity's a constant, and assuming that the drag curves roughly match each other, the "down" forces on the way up are higher than the "down" force on the way down.

Rusty, my Aunt Petunia's patootie...you just answered for me a question that's been mildly bothering me for years.

iapetus
July 22, 2005, 06:37 PM
These ones all have their guns pointing down, although they don't look particularly ready for action either...

http://www.timesonline.co.uk/article/0,,22989-1703933,00.html

RyanM
July 22, 2005, 06:55 PM
I forget how to do the actual math, but in the absence of air resistance, a bullet fired straight up will indeed hit the ground at muzzle velocity. So no firing guns upwards on the moon! :neener:

With air resistance, terminal velocity is pretty limited. Someone, I can't remember who right now, did an experiment decades ago with M2 ball (.30-06, not .50 BMG) fired straight up. Terminal velocity was 200-ish FPS, and one of the bullets hit a wooden dock on the way down, making a 1/8" deep dent. 200 FPS can still kill you, though. That's probably all the velocity some of those really tiny black powder derringers are capable of, and those've sent many a gambler to an early grave.

Mad Hatter
July 22, 2005, 10:50 PM
The numbers I've got for falling bullets are for a .308 150 gr. flat base: 300 fps, 30 ft-lb. It probably wouldn't do more damage than a bruise and a headache if the person was standing up. But I'm not going to volunteer to stand under one, either. That's gonna HURT.

Eightball
July 22, 2005, 11:36 PM
After reading all of this physics of "if it goes up, will it come down at the same speed?" stuff, my head's beginning to hurt..... :eek:

Gunwalker.44
July 23, 2005, 12:46 AM
In the good old days the only Bobbies armed were rare. (#10 Downing St
and places like that). When circumstances warranted they were armed
with whatever surrendered or otherwise available guns they had.
Used to be a great sight, Bobbies in uniform, one with a us military holster
complete with a 1911, next one with a full two gun Western rig and
so on. Yes, they didn't do the 'stop police' stuff, just Bang, gotcha.

entropy
July 23, 2005, 12:46 AM
They're all just slung on a single point, so they of course will be pointing down; these guys look a little more like a reaction force that the preceding pics. The guy in the pic with the gal looks like someone Wackenhut would reject, and they aren't the pickiest. ;)

c-bag
July 23, 2005, 05:50 PM
The UK cops look like decoration, the US cop looks like he's ready to get down and dirty.

True, but on the other hand they do have some downright snazzy hats. :neener:

Firethorn
July 24, 2005, 12:24 AM
Indeed, in a vacuum, a bullet's down path would be as fast as the up path. However, when you put air resistance into the bargain, it resists movement, period. Thus, the bullet doesn't go up as high, and when it comes down, it stops gaining velocity when it reaches 'terminal velocity', where air friction = gravity acceleration.

From my understanding, bullets can, and have, killed people from being shot into the sky. But it's more along the lines of a simple construction type hard hat would be protection, rather than a full-bore kevlar combat helmet. I'd imagine that larger, longer bullets, having a higher profile density, would have a higher terminal velocity, thus become more dangerous.

Radagast
July 24, 2005, 12:55 AM
Just the other day the Australian press posted a picture of our gun grabbing prime minister on hiatus in London. Out for a photo op jog, his british security detail were standing around in much the same manner. At least the one pointing his MP5 where the PM was about to step had his finger off the trigger. Otherwise there was no awareness of muzzle direction at all. I suppose there would have been some ironic justice if a man who is on record that only the police should have guns was shot by his police bodyguard, but I'm glad it didn't occur.

GunGoBoom
July 24, 2005, 03:26 PM
Firefighter, I must ask whether you are the 'engineer' of your fire dept, meaning that you drive the big red truck to the fire (like a train engineer)? Or maybe a chemical or electrical engineer, because your statement is quite incorrect. The terminal vel of the bullet dropping from the sky will nowhere approach its muzzle velocity - and it's in no way related to the MV - it's related only to terminal velocity if coming more or less straight down, which is determined by wind drag vs. gravity. P95 is exactly correct. It IS, however, still plenty enough to kill someone, if hit in the head or spinal cord, and therefore unwise to intentionally shoot in the air.

However, I must point out a couple of other incorrect or misleading statements by people in this thread. In the event of an ND, having a bullet fired into the concrete jungle of a city from a low ready position (into the ground at an angle) is no less hazardous to bystanders than shooting up into the air at an angle - in fact the danger of ricochet to nearby people is far greater than someone being hit from a falling bullet at a distance.

Second, with respect to the english officer who is holding the pistol grip with his forearm UNDER the buttstock of the rifle - this is not necessarily a deterrent to quick deployment - one can easily lift the end of the buttstock up and over the rear arm and then down into the crotch of the shoulder just as quickly as pulling it up under the arm - neither is as good as having the longarm already shouldered, with a good sling and a low ready, but failing that, what the english cop is doing is no worse than holding the pistol grip over the buttstock. However, the other guy, who is just holding the base of the buttstock - that is silly and would slow him down if something happened.

As for judging one's training by the *look on their faces*? WTH?

carebear
July 24, 2005, 03:39 PM
GGB,

Just guessing but I would think a round impacting concrete at a close to 45 or steeper angle about 3 ft. from the muzzle would be more likely to disintegrate against the concrete or bury itself in the asphalt than to ricochet.

Most ricochets I've seen on concrete were fairly shallow angle impacts.

I think the threat is greater for a round to come down on someone blocks away rather than skip back up from such a steep impact.

UberPhLuBB
July 24, 2005, 05:50 PM
^ Ditto. It might throw some asphalt chunks but it would almost certainly disintegrate.

Riktoven
July 25, 2005, 03:17 PM
I have a sneaking suspicion that most of the bullets that just "fell out of the sky and killed someone" weren't shot straight up. While terminal velocity may be 200 fps, that is only one vector of movement of any non vertical shot. If the shot was fired at 45 degrees, that bullet is going to be moving a lot faster than 200 fps when it comes down (200fps down, X fps in the horizontal vector of travel).


As long as we're discussing physics, anyone know what would REALLY happen if I dropped a penny from the observation deck of the CN tower? Physically to the concrete below I mean, not legally to myself.

Control Group
July 25, 2005, 03:44 PM
As long as we're discussing physics, anyone know what would REALLY happen if I dropped a penny from the observation deck of the CN tower? Physically to the concrete below I mean, not legally to myself.
Nothing notable.

Mythbusters covered this one a while back. They determined maximum velocity of a falling penny (by dropping it down a tube, and increasing airflow from the bottom up until the penny stayed suspended), then constructed a device to fire the penny down at somewhat more than that velocity. By the end, Adam was holding his hand under the gun. Even he admitted, though, that it really stung when the penny hit him in the same spot the second time.

They also rigged up an actual gun to drive the penny downwards at bullet speeds (~1000 fps?), and even that didn't materially damage the concrete. Basically, a penny just doesn't have enough mass to be a good kinetic energy carrier.

For a somewhat more scientific analysis (I love the Mythbusters, but scientists they're not), check out http://www.jimcarson.com/a/000148.shtml

Jim K
July 25, 2005, 03:44 PM
"I forget how to do the actual math, but in the absence of air resistance, a bullet fired straight up will indeed hit the ground at muzzle velocity."

Huh? Sorry, but not true.

When a bullet is fired straight up, it reaches a point in the air at which it stops before starting back down. (Try it with a baseball.) Since it has stopped, it will achieve the same terminal velocity as if it were simply dropped from that point. Since a bullet coming straight down (on Earth) will gain velocity at 32 fps/s in a vacuum, it will reach a terminal velocity based on its time of return. The muzzle velocity of the rifle that fired it is a factor only in that the more powerful the rifle the farther up the bullet will go, so its downward time of drop will increase, increasing its terminal velocity slightly. But it would never come anywhere near muzzle velocity.

Jim

odysseus
July 25, 2005, 03:52 PM
The numbers I've got for falling bullets are for a .308 150 gr. flat base: 300 fps, 30 ft-lb. It probably wouldn't do more damage than a bruise and a headache if the person was standing up. But I'm not going to volunteer to stand under one, either.

Thing is, it's parabolic. I think your example is about dropping a round from like the empire state building or something. So it depends on the angle and attitude when fired. It is going to retain a lot of energy normally, since it is not going to loose all of it's energy to friction and gravity. That's how some people can die from a ND into the air, which is mostly the situation if that round finds a person as a landing.

Control Group
July 25, 2005, 04:08 PM
When a bullet is fired straight up, it reaches a point in the air at which it stops before starting back down. (Try it with a baseball.) Since it has stopped, it will achieve the same terminal velocity as if it were simply dropped from that point. Since a bullet coming straight down (on Earth) will gain velocity at 32 fps/s in a vacuum, it will reach a terminal velocity based on its time of return. The muzzle velocity of the rifle that fired it is a factor only in that the more powerful the rifle the farther up the bullet will go, so its downward time of drop will increase, increasing its terminal velocity slightly. But it would never come anywhere near muzzle velocity.
Sorry, this is wrong. And it's easily demonstrated. Absent air resistance, it will reach the ground (actually, it will reach the altitude at which it left the muzzle) at exactly its muzzle velocity. Consider:

Assume the bullet leaves the muzzle at 3200 fps, straight up. Gravity accelerates it down at 32 feet per second per second. That means it will take 100 seconds to reach zero velocity (relative to the planet, that is). Since we're dealing with constant acceleration, it's easy to figure average velocity, it's the average of initial velocity and final velocity, so 1600 fps. 1600 fps over 100 seconds is 160,000 feet.

Now, if you're right, and the bullet never reaches 3200 fps again, it should take longer than 100 seconds for it to return (since, starting from zero, it has to reach 3200 fps to average 1600 fps, which will cover 160,000 feet in 100 seconds). So it will be accelerating due to gravity for at least 100 seconds.

Of course, 100 seconds of accelerating at 32fps/s will give it a final velocity of 3200 fps.

P95Carry
July 25, 2005, 04:15 PM
Riktoven - welcome :) anyone know what would REALLY happen if I dropped a penny from the observation deck of the CN tower? Yep - it'll be a head or a tail! :D :neener:

jaysouth
July 25, 2005, 05:04 PM
Can't speak to doctrine for police in U.K., but the British Army has been carrying muzzle down with the butt toughing the strong shoulder since their first auto loading (FAL/SLR) weapons were issued in the late 50s.

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