Ballistic thought experiment


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Kobun
November 22, 2003, 12:45 AM
This thread got me thinking (Too much? ;)): Mag 'Cocktails' (http://www.thehighroad.org/showthread.php?s=&threadid=51102)

a closely spaced double tap with one lite & fast round and one heavy & slow round will do more damage than two lite & fast rounds or two heavy & slow rounds
Well, may be the idea is to have both bullets impact at the same exact time? :)

Lets say:
You can fire two rounds in 0.15 seconds.
Your gun is a 9mm pistol.
You have the heavy bullet in the chamber, and then a light, heavy, light... And so on.
Heavy bullet is XTP 147gr @ 1050fps
Light bullet is XTP 115gr @ 1300fps
You and BG are standing on a totally flat horizontal surface.

Answer these questions:[list=1]
How far away has the BG got to be for the bullets to impact at the exact same time?
How long is the time of flight for the first bullet? Can you figure out the same for the second? ;)
Will the BG have moved out of the line of fire by the time the bullets reach him?
Did you hit him? What do you do if you missed?
Is it a righteous shoot at this distance?
Does the BG actually stand a chance to hit you? Or to harm you in any way?
Will you face criminal charges?
Will the bullets actually reach the BG?
What will their velocities be?
Will they expand?
Does the manufacturer guarantee expansion at these velocities?
At what angle do you need to tilt the barrel? And how much hold over do you need?
Will this be the same for both the heavy and the light bullet? (Hint, NO!)
Do you have time to calculate a new angle for the second shot in that 0.15 seconds? Or have you taped a ballistic chart to your grip?
Is this chart now under your palm?
Is this chart laminated and up to date? Did you ever try to shoot with this data? Does it make the grip slippery?
What is the wind drift like?
Is there a chance you forgot to chamber a heavy bullet first?
What happens if you forgot?
Where will the light (now first) bullet impact, since you fired what you thought was the heavy bullet?
How far between will the impacts be, as you fired a second time, thinking this was the light bullet?
How could you be sure the BG was actually a threat?
Don't you just wish you brought your rifle?
What rifle did you wish you had brought?
Can you carry that rifle all day, by yourself?
[/list=1]

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Kamicosmos
November 22, 2003, 12:53 AM
*wakes up, wipes drool from corner of mouth. Flips a few pages in the algebra book*

'...Mmmm Uh....1812 in Vermont...'


:D

Sunray
November 22, 2003, 01:23 AM
"...a closely spaced double tap with one lite & fast round and one heavy & slow round will do more damage than two lite & fast rounds or two heavy & slow rounds..."
One round properly placed will do more than any two hypothetically fired round.

rayra
November 22, 2003, 04:55 AM
With a split time between rounds of "0.15 seconds" what the hell difference could it POSSIBLY make?
Nonsense.

mete
November 22, 2003, 06:56 AM
The morke tiden is warping your mind.

BluesBear
November 22, 2003, 07:24 AM
The easy answer would be ... NEVER.


Supposing 870fps (.45auto) and .15 seconds between shots.

Consider this;

The first bullet has traveled almost 50 yards BEFORE you fire the second shot.

So the second bullet would only catch up with the first bullet IF it hit where the first one had already impacted.*

:rolleyes:

a closely spaced double tap with one lite & fast round and one heavy & slow round will do more damage than two lite & fast rounds or two heavy & slow rounds I know of no factual data to support this claim.
If you do please share.


(*unless it was fired in outer space and even then it would take a damn long time for it to catch up)

Double Naught Spy
November 22, 2003, 08:51 AM
Okay, you are on a train going from Austin, Texas to Reno Nevada. The train is traveling at 39 miles per hour. Another train on a parallel track is heading from Reno to Austin at 47 miles per hour. The two trains are due to pass outside of El Paso on level ground. You are the shooter on the Outbound from Austin train and shooting a 9 mm traveling at 1050 fps and the Inbound to Austin has a shooter shooting a 45 acp out of an itty bitty Kimber traveling at 770 fps. You are in the dining car and he is in the lavatory. Determine at what distance each would have to shoot to hit the other person for the impacts to be simultaneous and then determine the name of the conductor's sister's first pet hamster.

Sorry, I did the SAT and GRE. These sorts of questions usually seemed then as they do now.

RecoilRob
November 22, 2003, 08:53 AM
Hypothetically speaking,

A light and fast, rapidly expanding and SHALLOW penetrating bullet followed by a heavy, relatively slow and DEEP penetrating bullet WOULD have the potential to do more damage to tissue in the strike area than two of either.

But.......This is assuming that you CAN place two rounds close together on the target. Bad assumtion, proven out by countless shootings. Lots of guys are lucky to get ONE round COM on a BG so you better make it one of the deep penetrating ones to give it the best chance of doing the job. Rob

Lone_Gunman
November 22, 2003, 09:13 AM
The original quote was very misguided, and therefore any mathematical analysis of it is also misguided.

Crap in = Crap out

Harry Tuttle
November 22, 2003, 10:31 AM
First Hampsters are always named Fluffy

BryanP
November 22, 2003, 10:42 AM
Heavy bullet is XTP 147gr @ 1050fps
Light bullet is XTP 115gr @ 1300fps

Given those numbers they could only hit simultaneously if he was standing precisely 37.5 feet away from you. (250fps difference x .15) There's also the problem with the sights only being adjusted for one of them. It's an interesting idea but not practical.

Apple a Day
November 22, 2003, 10:43 AM
The bullets would hit the target after .48 seconds.
x=v(t) for both bullets, or distance = velocity (time)
The slower bullet is fired first so it's time is t+.15 seconds compared to the faster bullet

x=1050(t+.15) for the slower bullet
x=1300(t) for the faster bullet
Since they go the same distance, you can set the two equal to each other and end up with .48 seconds=t. The slower bullet travels for .63 seconds.
Plug that back into one of the original equations and the distance would be 624 feet. If you fired completely horizontally that would mean that the bullets would also have dropped 3.7 feet and 6.4 feet, respectively, so they wouldn't really hit at the same point. All of that is neglecting air resistance.
To hit at the same point, you'd have to loft them at different angles and it's too early on a Saturday to hash all that out. :scrutiny:

Henry Bowman
November 22, 2003, 12:16 PM
I was told there would be no math on this forum . . .

Kobun
November 22, 2003, 12:44 PM
OK, to those that didn't get it,

THIS WAS JUST FOR FUN!
It has NOTHING to do with reality!!!

The first quote is from another thread, and it didn't get taken seriously there eighter.

standingbear
November 22, 2003, 03:36 PM
the hampster was known as "TEDDY" then had its name changed later to "stupid thing" as it bit everyone that handled it.

Navy joe
November 22, 2003, 05:16 PM
With regards to the 37.5 feet response, ummm..no. In .15 seconds the first bullet is 157.5 feet down range.

roscoe
November 22, 2003, 05:31 PM
You could try something like this with an AN94.

jdkelly
November 22, 2003, 07:04 PM
I'll play, I'll play...

1)
1050 ft/sec * t sec + 0.15 sec *1050 ft/sec = 1300 ft/sec * t sec, 157.5 ft = 250 ft/sec * t sec , t = 0.63


2)
819 ft / 1050 = 0.78 sec Bullet #1
819 ft / 1300 ft/sec = 0.63 sec Bullet #2

3) Not likely

4) No I'd miss. Then I'd point at you (after all you said he was a bad guy and the bg might have a long arm).

5-25) I'll leave these to the rest of the forum.

I'm sorry if I'm wrong

jkelly





1300ft/sec * 0.63 sec = 819 ft

jdkelly
November 22, 2003, 07:40 PM
1050 ft/sec + 39 mph (57.2 ft/sec) = 1107.2 ft/sec
770 ft/ sec + 47 mph (68.9 ft /sec) = 838.9 ft/sec

Assuming a barrel length of 5" for the 9mm then the opposing barrels would have to be in contact with each shooter (in the direction of travel), and the Kimber would have to have a 3.79 inch barrel.

1107.2 ft/sec * 4.52 msec = 5.00 inches
838.9 ft/sec * 4.52 msec = 3.79 inches

Sorry if I'm wrong,

jkelly

BluesBear
November 22, 2003, 07:58 PM
Both bullets are still in motion.

Using the example of the slow bullet's velocity of 1050 and the fast bullet's velocity of 1300 and .15 seconds between shots.

The fist bullet will have traveled 157.5 feet* when the second bullet is fired.

*not accounting for loss of velocity due to drag

One second later the first bullet will have travelled 1207.5 feet.*
While the second bullet will have travelled 1300 feet.*

Now, if ANY of y'all can hit a man sized target at 400 YARDS - rapid fire, with a handgun, then you're a much better shot than I am.

Standing Wolf
November 22, 2003, 08:50 PM
# How far away has the BG got to be for the bullets to impact at the exact same time?
# How long is the time of flight for the first bullet? Can you figure out the same for the second?

3.1275 and 13/17ths plus about a third of a smidgen. I bet you thought I didn't know how to do story problems, didn't you?

ceetee
November 22, 2003, 09:29 PM
I got a "60" on my SAT's... How did I do?

MeekandMild
November 22, 2003, 09:44 PM
You can't get there from here. This is the sort of thing which would require extensive hands-on testing. :what:

MeekandMild
November 22, 2003, 09:49 PM
You can't get there from here. This is the sort of thing which would require extensive hands-on testing. :what:

Highland Ranger
November 22, 2003, 10:55 PM
I like the yellow mustard.

Steel
November 24, 2003, 11:37 AM
(in your best redneck voice)

Dang, you college boys and your dadburn 'rithmatic foolishness!

BluesBear
November 24, 2003, 04:19 PM
When I wuz still in Shcool, and they was larning me rithmatic and they wanted to put me in algaebra.
I said "why do I need to larn about algae bras? I didn't even know algae had bo... nevermind."

So there i were in algaebra class larning stuff when the teecher points to the writin board ans says "Pie Are Square"

I rised my hand and told him is was rong. "Any dang fool knows that pie are round, cornbread are square".

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