[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: More reasons for suppressors



> ----------
> From: 	Reese[SMTP:[email protected]]
> Reply To: 	Reese
> Sent: 	Friday, January 07, 2000 4:28 AM
> To: 	Bill Stewart; [email protected]
> Subject: 	Re: More reasons for suppressors
> 
> At 10:54 PM 1/6/00 -0800, Bill Stewart wrote:
> >>More reason to talk to Louigi about that silencer...
> >>
> >>L.A. Sheriff Shows Off High-Tech Hardware - (LOS
> 
> >>The illegal practice of firing into the air has resulted in 
> >>numerous injuries and deaths over the years. 
> >
> >I lost a high school classmate to random gunshots;
> >some kid was cleaning his gun in his garage and shot at a bird or
> something.
> 
> Sounds like a "falling bullet" fallacy to me.  Was the "kid" next door?
> 
> Falling bullets fall, at not more than ~300 fps - that's red rider bb gun
> @
> 20 ft velocities, or nearly super whammo sling shot velocities, for a .30
> cal 150 gr. bullet @ ~5 ft.
> 
> Was this person hit by an errant bullet, that "fell" through a window?
> 
> Sounds like a good reason to divest from glass, and invest in Lexan
> (kevlar, spectra, etc.)
> 
> Reese
> 
> 
> 
> 
I decided to see if I could find an informed answer on
this issue. This is harder than it used to be, since
Deja News has ceased it's original archival function,
and now pretends to be a 'product ratings' site.

Anyway - the answer seems to be that a spent falling
bullet isn't a big risk, but not something you'd shrug
off either.

> <begin copied material>
> From: [email protected] (Norman F. Johnson)Newsgroups: rec.guns
> Subject: falling bulletsDate: 19 Apr 1995 22:02:44 -0400Sean,
> # I don't know what terminal velocity for a bullet is,  but I do know that
> # it's still moving fast enough to cause injury.  Every year around the
> # Fourth of July,  the newspapers in the Bay Area where I used to live
> # would always have one or two stories of someone who got hit with a
> # falling bullet.  The injuries were occasionally severe.  The speed is
> # much less than muzzle velocity,  for sure,  but it's still dangerous.
> Regarding the above from, Hatcher's Notebook:
> "Among the many experiments carried out at Miami and Daytona, was
> this same one of vertical firing.  It was desired to find out how
> fast a bullet returned to earth and how dangerous such a bullet
> would be if it struck a soldier after dropping from a great
> height.  Many interesting things were learned from this test, and
> they are given in detail in the "Official Report of Vertical Time
> Flight for Small Arms Ammunition," in the files of the Ordnance
> Department.  Much of the information given below is from thatsource.
> "At Miami the firing was done from a platform built in the shal-
> low water of a protected inlet, where water was often calm.  A
> frame was built to hold a machine gun tripod so that the barrel
> pointed vertically.  Instruments were provided to check the angle
> of the barrel, and the tripod controls permitted any necessary
> changes in the barrel inclination to be made with ease and preci-sion.
> "Out of more than 500 shots fired after adjusting the gun--only
> four shots hit the platform.  One of the shots was a service
> 30.06, 150 grain flat based bullet, which came down base
> first...it left a mark about 1/16 inch deep in the soft pineboard.
> "Two more bullets struck in a pail of water and left only a
> perceptible dent in the bottom of the pail.  One struck the edge
> of the thwart (seat across a boat, used by an oarsman) in the
> boat, and left a shallow indent...The last two bullets were 175
> grain boat-tailed.
> "It was concluded from these tests that the return velocity was
> about 300 feet per second.  With the 150 grain bullet, this
> corresponds to an energy of 30 foot pounds.  Previously, the army
> had decided that on the average, an energy of 60 foot pounds is
> required to produce a disabling wound.  Thus, service bullets
> returning from extreme heights cannot be considered lethal bythis
standard.
> "Most .30 caliber bullets seem to attain this final velocity, and
> it doesn't make any difference how far they fall.  Even if a
> bullet was fired downward from a very high plane, it would still
> reach the ground at the same velocity.  That is because the
> resistance increases very rapidly with increases in air speed.
> If the air resists the motion of the bullet a certain amount at
> 300 feet per second, it will resist three times as much at 600
> feet per second and nearly nine times as much at 1000 feet persecond.
> "A 150 grain bullet weights .021 pounds, and when, in falling, it
> reaches a velocity where the air resistance balances the weight,
> the velocity of the fall will no longer increase.
> "For a .30 caliber bullet of standard experimental shape, having
> a pointed nose of two caliber radius, the air resistance on the
> nose at 2700 fps. would be about 2.3 pounds; at 2000 fps. 1.5
> pounds; at 1500 fps. .89 pounds; at 1000 fps. .17 pounds; at 500
> fps. .04 pounds; at 350 fps. .025 pounds; at 320 fps. .021
> pounds, balancing the weight of the bullet and stopping any
> further increase in velocity in the case of a falling bullet."
>      ****************************************************God Bless!Norm
> 
> <end quoted material>
> 
You might also want to look at:
http://www.povn.com/~4n6/index.htm

Note that they are referring to producing 'disabling wounds'
in a soldier - presumably a healthy young man, wearing a 
uniform and a helmet.

A bare-headed civilian in a tee-shirt is considerably more
vulnerable.

A risk which is reasonable to ignore for soldiers in combat 
is not neccesarily acceptable for civilians in peacetime.
Even if only 1% of returning bullets have the bad luck to
injure someone (fatally or otherwise) it's not acceptable to
fire randomly into the air in a densely populated area simply
because one likes to hear loud bangs.

Lets consider a thought experiment. If a falling bullet has
a terminal velocity of 300 fps, I think you'll agree that something
with 10x the weight and the same crossectional area will do the same
damage at 30 fps.

I'll take 10 of your slugs, solder them together head-to-tail , and
attach light tailfins to the rear end. This makes something like a
heavy metal dart (it should weigh 3-4 ounces). You can stand on the
ground, while I drop this dart on your head from the top of a 2 story
building (gravity's accelleration is about 32 ft/sec/sec - from a
15 ft height (above your head) an object will be at about 30 fps
velocity when it hits). You can tell us if it hurts. We could repeat
the experiment with you facing upwards, while I aim at your eyes.

It's not *likely* to kill you, but it could. 

Peter Trei