Shotgun slugs can knock people down? - Physics
Jon Oblad
who might understand this explanation better. The context is the
standard "knockback" debate of firearms, i.e. "Can you knock a person
down by shooting them without knocking yourself down?".
***begin quoted material***
In regards to the "knocking down" question. A quick lesson in physics
Force = Mass x Acceleration
Thus, force = newtons in metric (which I'll use for my calculations,
as it's simpler).
To wit: A typical shotgun slug weighs 1 oz. 1oz translates to roughly
29g. If we assume a typical impact velocity is 1000fps, this
translates to roughly 300m/s
Now, when a shotgun slug hits a bulletproof vest [assume a vest that
could stop a typical shotgun slug], it comes to an almost
instantaneous halt. let's say it negatively accelerates from 300m/s to
0m/s in .01 seconds
This makes your acceleration 30,000m/s^2 Thus, your impact Force will
equal 28 grams x 3000m/s^2, or .028 x 30,000m/s^2
This calculates to 840 Newtons, which, in standard measures comes to
about 210lbs of force on impact. More than sufficient to knock the
average bloke flat on his rump.
And also notice that if the recoil impulse is spread out over a longer
time (as it must be, as the powder doesn't combust instantaneously,
nor does the slug immediately leave the barrel. If the recoil impulse
is spread over an interval of .5 seconds, notice that the resulting
force would be reduced to 1/50 of the slug's impact; eg roughly 4lbs
***end quoted material***
Make sense? Or is there something missing that wouldn't warrant that
conclusion?
- Jon Oblad
-----------------------------------------------------------
Learn about rec.guns at http://www.recguns.com
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searcher
> ...
Most of the people on firearms message boards don't seem to understand
the concept of impulse. Guess most haven't studied dynamics. They
don't realize that Newton's law was originally stated in terms of
impulse. But how do they explain things like martial artists breaking
bricks and such to themselves, materials that can withstand thousands
of pounds of force being applied gradually? I guess they think there
is some kind of deceptive "trick" being used to accomplish these
amazing feats by human "machines" that can only generate a few hundred
pounds of lifting force.
> ...
Frank Silbermann
Re: Can you knock a person down by shooting them without knocking
yourself down:
Jon Oblad <jon...@hotmail.com> : <c5v9d9$3bm$1...@grapevine.wam.umd.edu>,
# ...when a shotgun slug hits a bulletproof vest ... (and delivers its
# kinetic energy in an impact lasting 0.01 sec) ... this calculates to
# ... about 210lbs of force on impact.
#
# ... If the recoil impulse is spread over an interval of .5 seconds,
# the resulting force would be reduced to 1/50 of the slug's impact;
# eg roughly 4lbs
So how do you explain the fact that one football player cannot knock down
an opponent without himself bouncing to the ground in the opposite direction?
:-)
Thomas Reynolds
but stopping inside it makes for better results...the energy all gets
transferred.
"Jon Oblad" <jon...@hotmail.com> wrote in message
news:c5v9d9$3bm$1...@grapevine.wam.umd.edu...
> ...
Henry E Schaffer
Jon Oblad <jon...@hotmail.com> wrote:
#Here's something I read on another forum, would like input from people
#who might understand this explanation better. The context is the
#standard "knockback" debate of firearms, i.e. "Can you knock a person
#down by shooting them without knocking yourself down?".
#
#***begin quoted material***
#
#In regards to the "knocking down" question. A quick lesson in physics
#
#Force = Mass x Acceleration
#
#Thus, force = newtons in metric (which I'll use for my calculations,
#as it's simpler).
#
#To wit: A typical shotgun slug weighs 1 oz. 1oz translates to roughly
#29g. If we assume a typical impact velocity is 1000fps, this
#translates to roughly 300m/s
Let me try instead a 1 oz marble thrown hard - say 50 fps (34mph) -
which translates to roughly 15m/s.
#Now, when a shotgun slug hits a bulletproof vest [assume a vest that
#could stop a typical shotgun slug], it comes to an almost
Instead of hitting a bulletproof vest, it hits a stone floor tile that
the person has on his chest - and then bounces back
#instantaneous halt. let's say it negatively accelerates from 300m/s to
#0m/s in .01 seconds
Let's say it negatively accelerates from 15m/s to -15m/s (that's a
30m/s change) in .001 seconds.
#This makes your acceleration 30,000m/s^2
This makes your acceleration 30,000m/s^2
So, at this point we have the same mass and the same acceleration with
the marble as with the shotgun slug. Right? If so, then the rest of
the calculation should be identical for both.
#Thus, your impact Force will
#equal 28 grams x 3000m/s^2, or .028 x 30,000m/s^2
#
#This calculates to 840 Newtons, which, in standard measures comes to
#about 210lbs of force on impact. More than sufficient to knock the
#average bloke flat on his rump.
This means that the average bloke should be knocked flat on his rump
by being hit with this hand thrown marble.
#And also notice that if the recoil impulse is spread out over a longer
#time (as it must be, as the powder doesn't combust instantaneously,
#nor does the slug immediately leave the barrel. If the recoil impulse
#is spread over an interval of .5 seconds, notice that the resulting
#force would be reduced to 1/50 of the slug's impact; eg roughly 4lbs
I guess that this means that throwing a marble won't cause the thrower
to be knocked over backwards - which is consistent with my personal
experience.
#***end quoted material***
#
#Make sense? Or is there something missing that wouldn't warrant that
#conclusion?
If it makes sense for the marble, then it makes sense for the shotgun.
I don't think it makes sense for the marble - and that "momentum"
probably has something to do with this.
--
--henry schaffer
hes _AT_ ncsu _DOT_ edu
mike
> ...
These slugs would definately knock a human down
http://www.remington.com/ammo/shotshell/buckhammer.htm I don't know of
any other slugs except some specialty loads that have more knockdown
energy http://www.remington.com/ammo/shotshell/buckhammer.htm Its a 1
3/8 ounce with a muzzle energy of 3230 ft/lbs I know that is not
knockdown energy, but it will move a 3230 pound object a foot. I think
thats what i heard, I may be wrong about what foot pounds mean. I know
some new 3 inch magnum slugs have as much muzzle energy as a 270wsm
and a 300 H&H magnum, and the low end of a .300 win magnum. People
usually quote 12 gauge slugs as having 2000 ft/lbs of energy, but
lately I have seen lots of loads over 3000 ft/lbs. Like someone
pointed out I wouldn't want to shoot these in a light 12 gauge
Leslie Swartz
subleties of the point you made will be lost on most people.
Here's the point without the sublety: anything in Math is possible when you
break the rules.
The flaw of the original example is in the mathematical hokey-pokey used:
"You put the Time Variable in, you take the Time Variable out, you put the
Time Vairable in, then you shake it all about . . . "
The "knockdown" example makes a couple of critical conversions, but is very
sloppy with the units of the "calculations."
Like, I make a 7-figure salary (including all significant digits) . . .
(O.K., O.K., 210 "POUNDS" of "FORCE" is all well and good- but what about
the momentum? The inertia? The example implies that if a 210 lb man were
to sit on a steeel plate over a 12-guage and fired it, they would hover in
mid-air!)
Steve Swartz
"Henry E Schaffer" <h...@unity.ncsu.edu> wrote in message
news:c61d93$481$1...@grapevine.wam.umd.edu...
> ...
Paul Gettings
#
# In regards to the "knocking down" question. A quick lesson in physics
#
# Force = Mass x Acceleration
For the purposes of this discussion, life is much easier if we use an
alternate formulation: F = dp/dt = change in momentum vs. time. From
this definition (assuming everything is a C_1 or nicer function), we
can get that:
F*dt = dp
or that the specific impulse is equal to the change in momentum. This
is handy, since momentum must be conserved in the system; force and
energy need not be (our system is not accounting for chemical energy
in propellants, heat lost in friction, etc., so our system is open
w/respect to energy).
Momentum conservation implies that:
dp = 0
for the total system. Here, the system we will consider is the
shotgun slug and vest-wearing human ("target"). Before impact, the
total momentum is:
p = m*v (slug) + m*v (target)
For a target at rest, v = 0 ==> p (target) = 0, and so the initial
momentum, p0, is:
p0 = m*v (slug)
After impact, the slug and target move together, as a single entity,
so the final momentum is:
pf = ( m(slug) + m(target) )*v (slug-target entity)
The trick, then, is to find the final v of the slug-target entity.
# To wit: A typical shotgun slug weighs 1 oz. 1oz translates to roughly
# 29g. If we assume a typical impact velocity is 1000fps, this
# translates to roughly 300m/s
Now, we plug in numbers to find the slug momentum:
ps = mv = 0.029 kg * 300 m/s = 8.7 N-s
Assume the target is 80 kg (~175 lbs). Then we neglect the mass of
the slug (0.029 kg) and compute the final velocity of the target
(w/slug):
pf = m*v ==> 8.7 N-s = 80 kg * vf ==> vf = 8.7/80 = 0.1088 m/s
The human, if on a frictionless surface, in a vacuum, would be moving
~11 cm/s after being shot with a shotgun slug. The question is
whether this would knock a human down, assuming the human does not
react to pain, shock, etc.
So, the question is whether a human can produce the force needed to
bring their velocity to 0 before they hit the floor. So, if we assume
a human falls over backwards like a stiff board, we can compute the
time to swing a board to the ground, and use 1/2 the time as the
interval allowable for a human to recover. This time determines the
necessary acceleration of the human to recover, and hence the force.
For simplicity, assume the target is a single point of mass in the
center of the chest, and that this is ~1.5 m from the floor, and
connected to the floor via a massless, rigid rod. When the slug hits
this point, it will move it backwards at 11 cm/s, swinging it towards
the floor; the arc is of length 0.5*pi*r (1/4 of a circle), for
r=1.5m, or 2.36 m. At 0.11 m/s, this will take 0.68 sec to traverse
(including the effect of gravity).
The target thus has, say, ~0.34 seconds to recover an 11 cm/s
velocity:
0.11 m/s/0.34 s = 0.3235 m/s/s acceleration.
Hence, the target must exert a force of 25.9 N, or about 5.8 lbs.
[This is potentially in addition to the force required to lift part of
the body back up, after being pulled by gravity. This is ignored, as
it is extremely unlikely that a target will not be able to do this
normally with plenty of muscle force left over.]
Hence, the impact of a slug will _hurt_ due to the fast deceleration
of the slug (dt is small, and the impact area small), but the target
will not fall due to the force of the slug impact itself. The target
will perhaps stagger back a step to recover (or just twist the torso,
etc.). The target will fall due to losing a leg, getting knocked
unconcious, or being in severe pain. The effect of movies showing
that people fall down when shot also helps.
So why the different result from the F=ma argument? The answer is
time:
# Now, when a shotgun slug hits a bulletproof vest [assume a vest that
# could stop a typical shotgun slug], it comes to an almost
# instantaneous halt. let's say it negatively accelerates from 300m/s to
# 0m/s in .01 seconds
Here is where the use of F=ma gets tricky; the actual deceleration
time
needs to be carefully measured, and is critical for the final result.
If the deceleration time is 1 sec (absurd, but illustrative), the
force is very tiny. By comparing momentum, we removed this time
problem altogether.
# This calculates to 840 Newtons, which, in standard measures comes to
# about 210lbs of force on impact. More than sufficient to knock the
# average bloke flat on his rump.
But, the 840 N force computed above (assuming the dt is even
reasonably close) is applied for a _very_ short time. The resulting
motion of the target is small (0.11 m/s). The target would fall if it
cannot react in any way, and assuming it is infinitely rigid.
It should also be noted that humans are compressible. Hence, much of
the 840 N of force is actually absorbed in deforming the vest, and
human underneath. This force is not translated into motion of the
target, and hence does nothing to contribute to the knockdown of the
target.
--
That which does not kill you, may leave you with a nasty limp.
Old Dog
aspects.
The first is shock. No matter how much adrenaline the BG had going, the effect
of a 12 ga slug is going to be noticed pretty quick.
The other thing is balance. If you are hitting the exact center of mass at the
midline and the person is braced expecting the shot (and he would have to be
pretty damned stupid to stand there if he did) you might be able to rely on
physics for a solution. But in fact, the impact is more likely to impart a
twisting effect on the torso - assuming you even hit the torso and not a leg or
arm - or face - and as anyone with even minimal knowledge of martial arts (and
mine is VERY minimal ;o) can tell you, getting your opponent off-balance is one
of the most important keys to success. That being the case, I think it is very
unusual for an attacker to be able to remain on his feet after being hit, even
with a vest (which might or might not be sufficient to stop something with that
much force).
Oh, yeah, and 0.5 seconds is a AWFULLY long time when you're talking about the
velocity of a fired projectile, even a heavy slow one...
-Old Dog
"Jon Oblad" <jon...@hotmail.com> wrote in message
news:c5v9d9$3bm$1...@grapevine.wam.umd.edu...
> ...
-----------------------------------------------------------
George B
of a fired shotgun slug and see if you are still standing. A
no-brainer!
Tod Glenn
stev...@penn.com (searcher) wrote:
# jon...@hotmail.com (Jon Oblad) wrote in message
# news:<c5v9d9$3bm$1...@grapevine.wam.umd.edu>...
# > ...
# Most of the people on firearms message boards don't seem to understand
# the concept of impulse. Guess most haven't studied dynamics. They
# don't realize that Newton's law was originally stated in terms of
# impulse. But how do they explain things like martial artists breaking
# bricks and such to themselves, materials that can withstand thousands
# of pounds of force being applied gradually? I guess they think there
# is some kind of deceptive "trick" being used to accomplish these
# amazing feats by human "machines" that can only generate a few hundred
# pounds of lifting force.
That's force applied to a very small area. Bricks, for example, hold
sataic loads sporead over their entire horizontal surface. What we are
really talking about here is not force, but pressure. 200 pounds may
not be much, but when applied to a one inch area is a different matter.
In the case of the bullet, it's momentum transfer. Not the same thing at
all.
--
----
Tod Glenn
mailto:webm...@cordite.com
http://www.cordite.com
Tod Glenn
jtb...@uncg.edu (mike) wrote:
# jon...@hotmail.com (Jon Oblad) wrote in message
# news:<c5v9d9$3bm$1...@grapevine.wam.umd.edu>...
# > ...
#
# These slugs would definately knock a human down
# http://www.remington.com/ammo/shotshell/buckhammer.htm I don't know of
# any other slugs except some specialty loads that have more knockdown
# energy http://www.remington.com/ammo/shotshell/buckhammer.htm Its a 1
# 3/8 ounce with a muzzle energy of 3230 ft/lbs I know that is not
# knockdown energy, but it will move a 3230 pound object a foot. I think
# thats what i heard, I may be wrong about what foot pounds mean. I know
# some new 3 inch magnum slugs have as much muzzle energy as a 270wsm
# and a 300 H&H magnum, and the low end of a .300 win magnum. People
# usually quote 12 gauge slugs as having 2000 ft/lbs of energy, but
# lately I have seen lots of loads over 3000 ft/lbs. Like someone
# pointed out I wouldn't want to shoot these in a light 12 gauge
Momentum is the easiest way to look at it. remember high school
physics. Assuming an inelastic collision where all energy is trasferred
to ther target:
M1V1=M2V2
The mass of the projectile in this case is 35g (1.25 oz). The velocity
is 469m/s. Assuming the target absorbs the bullet and all energy, and
the target is a 100 kilo adult male (220 lbs) you get
.035k * 469m/s = 100.035 * v2
The new velocity of the man and bullet is 160cm/sec. Some displacement,
obviously.
Put another way and using simple logic, if you can shoot the bullet and
not get kncked down, the target won't be either. Energy of motion is
conserved. Equal and opposite reactions.
2000 ft-pounds is nothing. A .458 will make almost 5000 ft-pounds at the
muzzle, and it's a relatively mild dangerous game cartridge. The .577
Tyrannosaurus makes 11,000 ft-pounds.
--
----
Tod Glenn
mailto:webm...@cordite.com
http://www.cordite.com
Ralph Wardlaw
Well, I don't necessarily agree with the .01 sec stop time for the slug. But
be that as it may, let's assume his numbers are correct and we have 210 lbs
force applied for 10 milliseconds. And, let's assume the upper body of the
victim weighs 100 lbs.
That weight is 1600 times that of the slug, so the acceleration of his upper
body
would be 1/1600 times that of the slug, or 18.7 m/sec^2 for .01 sec. So at
the end of .01 sec, his upper body would be traveling at 0.187 m/sec., and
would have moved (.187 x .01)/2=.0009 m, or less than one centimeter. I
think
I could recover from that very quickly. About like taking a body jab from a
boxer.
He further decides that the recoil impulse at the shooter end is spread out
over 0.5 sec. If the slug exits the barrel at 1000 fps, then it was probably
averaging about 500 fps while being accelerated in the barrel. For a 2 foot
barrel, that would take about 2/500=4 milliseconds. That is even
worse than his original assumptions about the victim end of the picture.
So the author of "the quoted text" has chosen numbers to prove his point,
that a slug would "knock a bloke on his rump". Must be from UK or Aus.
By the way, using his analysis, based on rigid body dynamics, the exact same
result would be obtained with 1 oz of #9 shot.
RW
mike
# over 0.5 sec. If the slug exits the barrel at 1000 fps, then it was probably
# averaging about 500 fps while being accelerated in the barrel. For a 2 foot
# barrel, that would take about 2/500=4 milliseconds. That is even
# worse than his original assumptions about the victim end of the picture.
#
# deleted>
#
#
#
#I don't know of many 12 gauge slugs that exit the barrel at 1000fps
that number seems a bit low, although that is irrelevant, I am just
pointing out slugs ae not that slow anymore. The magnum slugs at 1900
fps and over an ounce will most likely knock you over if you are off
gaurd and not paying attention, i.e you are not prepred to fire the
rifle. And yes 2000 ft/lbs isn't much, like I said there are 3.5 inch
magnum slugs that will do about twice that at close to 4000 ft/lbs,
Granted your standard veloctiy slug of an ounce is usually only going
about 1500 fps, but the magnum slugs are a different story, I had the
chance to shoot some today, and if i wasn't prepared to shoot or i was
interrupted I might have well fallen on my ass. I am not big and I am
not small, about 180 pounds give or take
Porc
# Re: Can you knock a person down by shooting them without knocking
# yourself down:
#
# Jon Oblad <jon...@hotmail.com> : <c5v9d9$3bm$1...@grapevine.wam.umd.edu>,
# # ...when a shotgun slug hits a bulletproof vest ... (and delivers its
# # kinetic energy in an impact lasting 0.01 sec) ... this calculates to
# # ... about 210lbs of force on impact.
# #
# # ... If the recoil impulse is spread over an interval of .5 seconds,
# # eg roughly 4lbs
#
# So how do you explain the fact that one football player cannot knock down
# an opponent without himself bouncing to the ground in the opposite direction?
# :-)
If you're a Broncos fan, this question doesn't apply.
-porc
Jon Oblad
# Forget all the math and physics. Just put yourself at the receiving end
# of a fired shotgun slug and see if you are still standing. A
# no-brainer!
The discussion was in the context of shooting someone wearing body
armor that the slug would not penetrate or flex (or flex enough to
matter, anyway), specifically the North Hollywood shootout.
- Jon Oblad
Ralph Wardlaw
I agree. I was just using the number from the original quoted message.
RW
TimR
I'll do some later when a calculator is handy <grin>.
If there's no vest, no knockdown; the slug just goes right through
and you fall forward. If you're not paying attention, you probably
don't have a vest either.
I have some doubts about the .01 sec deceleration. But if true, the
basic question is will a 200 pound force, applied for one-hundredth of
a second, knock you down? I think unlikely. Applied for ten seconds,
probably.
Second, for the target, F=ma is the wrong formulation. You need to
use T=I*(alpha). This is a rotational problem. Consider the feet as
a hinged connection to the ground. The torque arm is probably the
distance above the centroid or maybe center of percussion that you
hit. Hitting below that probably bends you forward.
Third, to fall over, the center of gravity needs to move outside the
base. Think of pushing on a vending machine - nah, nobody's ever done
that, okay a refrigerator. You can push it pretty hard, but unless
you get it far enough to have the center of gravity outside the base
it won't topple, it will return. If you're standing en pointe like a
ballerina, not much force for not much time might work; but with legs
spread a lot of force for more time will be needed.
So much for a non math approach.
bill
## of a fired shotgun slug and see if you are still standing. A
## no-brainer!
#
#The discussion was in the context of shooting someone wearing body
#armor that the slug would not penetrate or flex (or flex enough to
#matter, anyway), specifically the North Hollywood shootout.
#
#- Jon Oblad
And you think wearing the vest is going to matter? The blunt trauma received
from the temporary cavity produced in the anterior (front) wall of your chest
due to the vest's deformation will be more than enough to knock any man down.
The only vests that will not deform at all are level III, usually consisting of
ceramics and are worn outside the clothing. Totally impractical except for
SWAT/military users.
I think all the people who try to prove that this is possible "mathmatically"
just need to step back, take a breath and look at the _reality_ of the
situation. Anybody who wants to prove my "common sense" solution wrong is
welcome to put on my IIIA vest and let me shoot you. :-P
Really, folks seeing the cavity left in clay torsos wearing vests make it clear
that most people are likely to be knocked down by even handgun rounds. The use
of the vest actually causes most wearers more pain and "sense of impact"
because they feel more of the impact than if the projectile passed through
flesh/bone. I also wear a "trauma plate" with my IIIA and would not want to
take an impact from a pistol thru shotgun sized projectile.
bill
Car: '64.5 Mustang: 260 V8, 3 sp, factory a/c, SVO cam, Performer intake,
Holley 390 cfm carb, Pertronix, Hi-Po exhaust, 1.5" front & 1" rear drop,
Jacobs wires, Torq Thrust D's
Guns: Colt AR15, Sig P220, Moss. 590A1, Marlin 70P
purch2
which was adapted into a decent flick with Mickey Rourke.
It talks about a shotgun a Chinese gangster uses as, "an instrument
said to be powerful enough to turn over cars."
Hmmm... quite a shotgun. I'd say a .50 BMG would be hard-pressed to
turn a car over, let alone a man-portable shotgun.
Michael C. Dean
> ...
Gentlemen,
The fundamental formula of Physical Mechanics if F = MA (force is
equal
to the mass times the acceleration). This applies to the problem.
However,
there is a rub. The acceleration and the force are not linear and will
not submit to an analytical solution.
The momentary force is M * dv/dt. The integrated force might be called
the
impulse (I am dragging fragments of facts that are 54 years old in my
brain).
Anyway we really don't know the time dependat graf of the velocity,
and so
we don't really know the shape of the acceleration curve and
consequently the
shape of the force curve. At any point in time it might be 200 lbs or
not. Probably not.
A simple experiment could prove illuminate all of this, and probably
has been done somewhere. A target that has a sensor that measures
force without much bias of its own, and can respond in microseconds
could graph the impulse of the impact.
There is probably someone on this forum that does this kind of work or
knows someone that does. Force on car bumpers, engine mounts, etc. Let
them sneak out some sensors and do the experiments for us.
Remember that one well desingned experiment is worth
100,000 learned opinions.
SuperMag
Last summer I had the distinct pleaure (?) of trying some Winchester
Super-X 3" magnum 1.25oz. slug loads in an Ithaca model 87
Featherweight. I knew it was not going to be a piece of cake, so I
braced for recoil prior to pulling the trigger. It wasn't enough.
The shotgun recoiled in a most painful manner, as well as rotating
skyward and hitting me in the forehead and breaking my sunglasses.
Now I am 6'2", 220 lbs, but had I not been "braced for impact," the
recoil most certainly would have knocked me flat on my ass. So
assuming that Newton is spot-on and I am transmitting just as much
energy/momentum/mojo downrange as I am feeling my ownself, then yes,
my target would have been pronated just as spectacularly.
Huzzah.
SM
Herb Leong
bill <txars...@aol.com> wrote:
##The discussion was in the context of shooting someone wearing body
##armor that the slug would not penetrate or flex (or flex enough to
##matter, anyway), specifically the North Hollywood shootout.
##
##- Jon Oblad
#And you think wearing the vest is going to matter? The blunt trauma received
#from the temporary cavity produced in the anterior (front) wall of your chest
#due to the vest's deformation will be more than enough to knock any man down.
#The only vests that will not deform at all are level III, usually consisting of
#ceramics and are worn outside the clothing. Totally impractical except for
#SWAT/military users.
Bill,
That is the exact situation of the North Hollywood shootout: Bank
robbers with heavy non-concealed body armor.
/herb
Bryant
with sand (or dirt). Put them on a 2 x 12 mounted on two sawhorses. Put
them on the board first. Take your Mossberg 835 and shoot it. See if it
stays on the board. Mine fell over. With 3 and 1/2 inch 12 gage buckshot
and with slugs. I figure it weighed more than 150 pounds, and the slugs did
not go through the bag. 270 and 30-06 didn't knock it over, and 45 colt and
44 mag didn't either, but the 45-70 with 405 grain handloads did. Just what
I tried. (H)
> ...
Jon Oblad
[...]
# And you think wearing the vest is going to matter?
In the case of the North Hollywood bank robbery shootout it might very
well have, depending on what type of vest they were wearing. I think
that both Phillips and Matasareanu were wearing Level IIIA vests (or
something equivalent).
#Really, folks seeing the cavity left in clay torsos
#wearing vests make it clear that most people are likely
#to be knocked down by even handgun rounds.
You are talking about physical damage to the body making someone
collapse. This is different than the original subject, namely being
knocked down by the momentum of a moving object.
- Jon Oblad
Peter McMullen
Jon Oblad wrote:
# Here's something I read on another forum, would like input from people
# who might understand this explanation better. The context is the
# standard "knockback" debate of firearms, i.e. "Can you knock a person
# down by shooting them without knocking yourself down?".
#
It *is* momentum transfer we are concerned with here. Not
even considering the math, if the recoil momentum of the
wide shotgun butt is not enough to knock you down, a 5/8
inch diameter projectile passing through soft tissue (or
even hitting a vest) will not knock down your target;
assuming we are talking about two adult humans of average
weight and not simply a loss of balance. The bad guy may
fall down from psychological influence, direct central
nervous system damage, pain, or severe blood loss however.
Peter McMullen
Frank Silbermann wrote:
# Re: Can you knock a person down by shooting them without knocking
# yourself down:
#
# Jon Oblad <jon...@hotmail.com> : <c5v9d9$3bm$1...@grapevine.wam.umd.edu>,
# # ...when a shotgun slug hits a bulletproof vest ... (and delivers its
# # kinetic energy in an impact lasting 0.01 sec) ... this calculates to
# # ... about 210lbs of force on impact.
# #
# # ... If the recoil impulse is spread over an interval of .5 seconds,
# # the resulting force would be reduced to 1/50 of the slug's impact;
# # eg roughly 4lbs
#
# So how do you explain the fact that one football player cannot knock down
# an opponent without himself bouncing to the ground in the opposite direction?
# :-)
#
#
Inertia, body position/stance, balance ;-)
Peter McMullen
mike wrote:
# jon...@hotmail.com (Jon Oblad) wrote in message news:<c5v9d9$3bm$1...@grapevine.wam.umd.edu>...
# > ...
#
# These slugs would definately knock a human down
# http://www.remington.com/ammo/shotshell/buckhammer.htm I don't know of
# any other slugs except some specialty loads that have more knockdown
# energy http://www.remington.com/ammo/shotshell/buckhammer.htm Its a 1
# 3/8 ounce with a muzzle energy of 3230 ft/lbs I know that is not
# knockdown energy, but it will move a 3230 pound object a foot.
In a totally zero gravity, zero friction environment, and
assuming the same elasticity/density it would move a foot...
but at what velocity?
Momentum transfer is the mechanism that would theoretically
"knock back" a person. Momentum P equals Mass times
Velocity, P=MV. Momentum transfer is the function of the
ratios of the two masses involved, assuming equal elasticity
and density. 165 pounds equals 2640 ounces.
What you've got is 1.3 * 3000 = 2640 * x, or
1.3 * 3000 / 2640 = x = 1.48fps
Assuming the same density and elasticity of the objects,
zero gravity and friction, a 1.3 ounce object traveling at
3000 fps would impart a velocity to the impacted 165 pound
object of roughly 1.48 fps. That's the best case. Now throw
in elasticity, the relatively low density of tissue,
balance, friction, gravity... Do you really think this would
"knock back" a person to any degree of consequence?
--
"At this time, Google policy does not permit the
advertisement of websites that contain 'firearms and
ammunition'."
BOYCOTT GOOGLE
:-)
bill
#news:<c6763i$okf$1...@grapevine.wam.umd.edu>...
#
#[...]
#
## And you think wearing the vest is going to matter?
#
#In the case of the North Hollywood bank robbery shootout it might very
#well have, depending on what type of vest they were wearing. I think
#that both Phillips and Matasareanu were wearing Level IIIA vests (or
#something equivalent).
snip
#From everything we were told about the NH shootout I don't recall that there
was any evidence of the shooters being hit by slugs. In the videos it is
obvious they were taking hits but only pistol and possibly buckshot AFAIK.
Like I said, I don't remember all of the details but I'd be surprised if a
large number of patrolmen on scene even had slugs available. Our policy is
buckshot in the weapon, slugs available in the car. For some reason admin
seems to think that 9 pellets are less of a risk than 1 slug. If I were in
that position I'd be crapping my pants and then dumping my buckshot and loading
slugs only, but then I supply my own shotgun with 9 round magazine plus 4
rounds in the speed-feed and 6 rounds in the side saddle. Manual requires 5
rounds of buck, more than that is officer preferrence. The guys with issue
shotguns seem satisfied with the 5 rounds in the magazine only...
##Really, folks seeing the cavity left in clay torsos
##wearing vests make it clear that most people are likely
##to be knocked down by even handgun rounds.
#
#You are talking about physical damage to the body making someone
#collapse. This is different than the original subject, namely being
#knocked down by the momentum of a moving object.
#
#- Jon Oblad
True, I'm just saying that I think the reality outweighs or negates the
"mathmatics." Hell, you could knock somebody over with a .22 if circumstances
were perfect, the stars were aligned... Of course I _could_ also be biased
because math killed me in school. :-)
bill
Car: '64.5 Mustang: 260 V8, 3 sp, factory a/c, SVO cam, Performer intake,
Holley 390 cfm carb, Pertronix, Hi-Po exhaust, 1.5" front & 1" rear drop,
Jacobs wires, Torq Thrust D's
Guns: Colt AR15, Sig P220, Moss. 590A1, Marlin 70P
pc macdonald
# What you've got is 1.3 * 3000 = 2640 * x, or
# 1.3 * 3000 / 2640 = x = 1.48fps
#
I'm a degreed mechanical engineer. I don't have the time, inclination
or patience to work out this kind of stuff for fun, although I'll
accept your equations 'as is'.
Here's my point of reference: I've been told first hand by sherrif's
deputies who have had the pleasure of shooting rifled slugs into junk
autos for effect.
They've told me that the 1+ ounce slug fired from a combat shotgun is
the only thing they've ever shot at an automobile that will truly
penetrate the ENGINE BLOCK.
Or completely through the passenger compartment when shot from side to
side through a front door...
I don't know about you, but I have no doubt whasoever, even at my
extreme weight of 270 pounds, that I would be knocked head over heels
a couple of times over with that kind of impact. Period. Done.
I ain't no freakin' engine block!
nataS
news:c69fq0$p72$1...@grapevine.wam.umd.edu...
#
# In a totally zero gravity, zero friction environment, and
# assuming the same elasticity/density it would move a foot...
# but at what velocity?
In a zero gravity, zero friction environment, it'd move an infinite distance
in an infinite amount of time. If Jupiter were solid, with no atmosphere,
sitting still, and not subject to any other gravitational forces, the impact
of a wafting feather would start it moving. Wait long enough, it'll even
move a foot :-)
--
Knowledge is Power
Power Corrupts
Study Hard
Be Evil
Jon Oblad
[...]
# #You are talking about physical damage to the body making someone
# #collapse. This is different than the original subject, namely being
# #knocked down by the momentum of a moving object.
#
# True, I'm just saying that I think the reality outweighs or negates the
# "mathmatics."
Even then not necessarily. Any firearm that causes severe enough
internal bleeding will have 100% "stopping power". Actually stopping
someone is irrelevant, though, because there is only small
satisfaction in putting someone down *after* they have killed you.
Hhumans who resist psychological surrender are actually pretty tough
organisms, at least in the short term - short term being the amount
of time needed for a determined attacker to kill or seriously injure
you. I seem to recall that even if snap my fingers and magcially make
the heart explode (or pull a trigger and shred the heart with a round
of buckshot), an average person still has enough oxygen running around
in his system for at least 10-15 seconds of forceful activity. That's
plenty of time to run up and stab someone several times or empty a
Glock magazine.
Incidentally, this is where people bring up the "knock down" thing and
thus we are led (as this thread demonstrates) to the physics section
of the discussion.
- Jon Oblad
Jim Gaynor
"Tod Glenn" <webm...@cordite.com> wrote in message
news:c6311q$qs8$1...@grapevine.wam.umd.edu...
> ...
Tod that s the way I have always understood it. Nothwithstanding if you are
hit with a 12 ga RS you will get real sick and fall down fast but the
movies where people are flung off their feet - through windows etc -
strictly hollywood.
> ...
Jim Gaynor
shot will drop. The issue is there enough energy to physically knock them
off their feet. different matter.
"George B" <Yu...@webtv.net> wrote in message
news:c6311m$qs2$1...@grapevine.wam.umd.edu...
Banshee
well, I have 200lb deer knocked off of thier feet by 12ga slugs. I
mean slamed to the ground and slide to the side and not get up.
pc macdonald
# wide shotgun butt is not enough to knock you down, a 5/8
# inch diameter projectile passing through soft tissue (or
# even hitting a vest) will not knock down your target;
#
#
I sure don't buy it. Something that will penetrate the engine block
of an auto through the fender from 25 yards is sure going to knock
anybody on their ass.
Believe it.
Kevin D. Snodgrass
# # It *is* momentum transfer we are concerned with here. Not
# # even considering the math, if the recoil momentum of the
# # wide shotgun butt is not enough to knock you down, a 5/8
# # inch diameter projectile passing through soft tissue (or
# # even hitting a vest) will not knock down your target;
# #
# #
# anybody on their ass.
Unless the projectile also punches a hole through the human.
But then that human will probably fall down anyhow.
A couple things on this subject. First, most of the people
putting out equations are missing something very important.
Even with a hard vest, this will NOT be an ideal inelastic
collision. Projectile deformation, shifting of the vest,
heat (heat is a loss of energy), and probably other things I
can't think of right now must be considered. And in the
case where the person being shot does not have hard body
armor, you must also figure in the energy loss due to
created the massive tissue cavity.
Second, how many deer hunters do we have reading this
newsgroup? How many have hunted deer with shotgun slugs? A
big whitetail might weigh 350 lbs. Texas whitetail might be
about the same weight as an average male, say 175-200 lbs.
When shot, does the deer fall over from the impact of the
slug or the collapse of their legs? How many get hit, don't
fall down at all and run away, whether 10 feet or 1000 yards?
Third, and this one is really just conjecture here. I have
seen demonstrations on TV by some guy that invented some
appearantly quite good hard body armor. To demonstrate, he
would shoot himself in the stomach with a high power
handgun, I think it was a .357 Mag. (Didn't pay enough
attention) I have also heard that a .357 Mag will penetrate
an engine block, which was supposedly part of the reason why
certain police departments wanted them. This guy shooting
himself, at point blank range, with what I remember (maybe
incorrectly) to be an engine block penetrating firearm and
he does not fall over.
Do I expect someone shot with a 12ga slug to hit the ground?
Yes, I certainly do. But from the trama, muscle collapse,
shock, whatever, not the momentum of the slug.
--
Kevin D. Snodgrass
Help our soldiers in the field:
http://www.operationac.org/
Help our soldiers in the hospital:
http://www.woundedwarriorhospitalfund.org/
Peter McMullen
pc macdonald wrote:
# # It *is* momentum transfer we are concerned with here. Not
# # even considering the math, if the recoil momentum of the
# # wide shotgun butt is not enough to knock you down, a 5/8
# # inch diameter projectile passing through soft tissue (or
# # even hitting a vest) will not knock down your target;
# #
# #
# I sure don't buy it.
Well then you must be the greatist physicist since Einstein
Something that will penetrate the engine block
# of an auto through the fender from 25 yards is sure going to knock
# anybody on their ass.
It might penetrate a block, probably brittle cast iron or
aluminum... did it move it??? Two different things
--
"At this time, Google policy does not permit the
advertisement of websites that contain 'firearms and
ammunition'."
BOYCOTT GOOGLE
:-)
-----------------------------------------------------------
J. Del Col
# # It *is* momentum transfer we are concerned with here. Not
# # even considering the math, if the recoil momentum of the
# # wide shotgun butt is not enough to knock you down, a 5/8
# # inch diameter projectile passing through soft tissue (or
# # even hitting a vest) will not knock down your target;
# #
# #
# anybody on their ass.
# Believe it.
Not really. The knockdown effect is more a product of disruption of
the nervous system than one of sheer momentum. If the slug kills the
person instantly, of course he'll fall over, but that isn't the result
of
momentum alone.
People aren't -always- knocked flat by .50 BMG rounds, and those
deliver a hell of lot more energy than a shotgun slug.
If the shooter isn't knocked down by recoil, the slug's momentum alone
won't necessarily knock down the person being shot.
J. Del Col
Bryant
75 yards, running away from me. It was shot by another hunter. The bullet
hit the right hindquarter and exited the left shoulder, and took off part of
the lower jaw. It too the deer's ass end and lifted it over its antlers.
The deer wound up facing me, lying in the path. That my friend is
knockdown, no matter how you describe it. I also hunted wild domestic pigs
in South Carolina from tree stands using a remington 1100 with Brenike
slugs. Every pig I shot was knocked ass over end. Some got up, but all of
them went down. Hard. Hit one in the shoulder, and it might not kill it,
but it knocked the hell out of the pig. I don't try to explain it, I just
use what works. (H)
# pc macdonald wrote:
#>
# newsgroup? How many have hunted deer with shotgun slugs?
pc macdonald
# Well then you must be the greatist physicist since Einstein
And you, sir, appear to be the greatest diplomat since Idi Amin.
Leslie Swartz
absolutely nothing whatsoever to do with the actual question being asked:
"Will a 12 gage slug KNOCK a person DOWN."
NOT
- Will it make them fall down
- Will it make them collapse
- Will it make them stumble, if running
- Will it make them do a cartwheel, if performing gymnastics
- Will it make them crash into a telephone pole, if driving
- Will make them lose oil, if a car engine
- Will it make them vote Democrat, if stupid
- ET-FREAKIN-CETERA
Sheesh!!!!!
Causing a running pig/deer/goat/Chevy Nova SS to stumble/fall/cartwheel/buy
a vowel HAS NOTHING WHATSOEVER TO DO WITH HTE QUESTION!!!!!!!!!
Steve
Tod Glenn
"Kevin D. Snodgrass" <kdsno...@yahoo.com> wrote:
# Third, and this one is really just conjecture here. I have
# seen demonstrations on TV by some guy that invented some
# appearantly quite good hard body armor. To demonstrate, he
# would shoot himself in the stomach with a high power
# handgun, I think it was a .357 Mag. (Didn't pay enough
# attention) I have also heard that a .357 Mag will penetrate
# an engine block, which was supposedly part of the reason why
# certain police departments wanted them. This guy shooting
# himself, at point blank range, with what I remember (maybe
# incorrectly) to be an engine block penetrating firearm and
# he does not fall over.
Rich Davis, founder of Second Chance body armor. I've see him being
shout with a 12 gauge slug, as well as by an AK. There's someone who
(literally) stands behind his product.
And no, he did not fall over after being hit with a shotgun slug.
--
----
Tod Glenn
mailto:webm...@cordite.com
http://www.cordite.com
Tod Glenn
"Bryant" <brya...@earthlink.net> wrote:
# I hunt deer with a 45-70, using 405 grain lead handloads. I shot a deer at
# 75 yards, running away from me. It was shot by another hunter. The bullet
# hit the right hindquarter and exited the left shoulder, and took off part of
# the lower jaw. It too the deer's ass end and lifted it over its antlers.
# The deer wound up facing me, lying in the path. That my friend is
# knockdown, no matter how you describe it. I also hunted wild domestic pigs
# in South Carolina from tree stands using a remington 1100 with Brenike
# slugs. Every pig I shot was knocked ass over end. Some got up, but all of
# them went down. Hard. Hit one in the shoulder, and it might not kill it,
# but it knocked the hell out of the pig. I don't try to explain it, I just
# use what works. (H)
I shoot a .458 win mag on occasion, using 500 gn softpoints in front of
72 gns of 4895. I have hit exactly one deer with it, a muley, in the
left side, from about 50 yards through moderate vegietation.
It grunted once, stood still for about five seconds, then stumbled to
the ground. That's with muzzle energy well beyond the .45-70.
--
----
Tod Glenn
mailto:webm...@cordite.com
http://www.cordite.com
Tod Glenn
Jim Gaynor <jga...@optonline.net> wrote:
# "Tod Glenn" <webm...@cordite.com> wrote in message
# news:c6311q$qs8$1...@grapevine.wam.umd.edu...
# > ...
# Tod that s the way I have always understood it. Nothwithstanding if you are
# hit with a 12 ga RS you will get real sick and fall down fast but the
# movies where people are flung off their feet - through windows etc -
# strictly hollywood.
All you have to do is test the theory is get a couple of 100 pound sacks
of sand and stand them on a barrel, then shoot them with a 12 gauge.
You won't knock them over.
--
----
Tod Glenn
mailto:webm...@cordite.com
http://www.cordite.com
Peter McMullen
Bryant wrote:
# I hunt deer with a 45-70, using 405 grain lead handloads. I shot a deer at
# 75 yards, running away from me. It was shot by another hunter. The bullet
# hit the right hindquarter and exited the left shoulder, and took off part of
# the lower jaw. It too the deer's ass end and lifted it over its antlers.
# The deer wound up facing me, lying in the path. That my friend is
# knockdown, no matter how you describe it.
If you run full speed and trip on a rock, you will end up
ass over elbows as well. Has a *lot* more to do with the
momentum of the deer as it stumbles on the run when hit...
--
"At this time, Google policy does not permit the
advertisement of websites that contain 'firearms and
ammunition'."
BOYCOTT GOOGLE
:-)
-----------------------------------------------------------
John Miller
# Third, and this one is really just conjecture here. I have
# seen demonstrations on TV by some guy that invented some
# appearantly quite good hard body armor. To demonstrate, he
# would shoot himself in the stomach with a high power
# handgun, I think it was a .357 Mag. (Didn't pay enough
# attention) I have also heard that a .357 Mag will penetrate
# an engine block, which was supposedly part of the reason why
# certain police departments wanted them. This guy shooting
# himself, at point blank range, with what I remember (maybe
# incorrectly) to be an engine block penetrating firearm and
# he does not fall over.
But in the case of shooting yourself, and the bullet being entirely
"absorbed" by vest, action and reaction cancel each other out almost
exactly.
Main think to keep in mind, I think, is that the force at the receiving end
can be no greater than that at the shooting end. But the shooter is
expecting it.
--
John Miller
Email address: domain, n4vu.com; username, jsm
I must Create a System, or be enslav'd by another Man's;
I will not Reason and Compare; my business is to Create.
-William Blake, "Jerusalem"
J. Del Col
# Kevin D. Snodgrass wrote:
# # Third, and this one is really just conjecture here. I have
# # seen demonstrations on TV by some guy that invented some
# # appearantly quite good hard body armor. To demonstrate, he
# # would shoot himself in the stomach with a high power
# # handgun, I think it was a .357 Mag. (Didn't pay enough
# # attention) I have also heard that a .357 Mag will penetrate
# # an engine block, which was supposedly part of the reason why
# # certain police departments wanted them. This guy shooting
# # himself, at point blank range, with what I remember (maybe
# # incorrectly) to be an engine block penetrating firearm and
# # he does not fall over.
#
# But in the case of shooting yourself, and the bullet being entirely
# "absorbed" by vest, action and reaction cancel each other out almost
# exactly.
They always do, but not in the sense you suggest. Think about it.
J. Del Col