Re: New Life for Millennium's End

[Brian McDonald <Brian_mcdonald@xxxxxxxxxxxx>]

"Robert J. Hansen" wrote:

> > What i am saying is that if you take a headshot with your barret at
> > 1200m and hit perfect on target, then zoom back and take a headshot at a
> > different range, the point of impact can differ by as little as 1mm to as
> > large as 30cm.  Scopes are only as unbalancing as you let them be.
>
> More than 30cm for a 1200m shot.  Muzzle velocity of a .50 fired from a
> Barrett is 854m/s.  That means at 1200m it's been in flight for one and a
> half seconds.  According to physics, it'll drop by one-half the force of
> gravity multiplied by the square of the time it's in freefall--or,
> (.5)*(9.8)*(1.5)*(1.5).  Do the math; gravity will drop the bullet by about
> eleven /meters/.  On top of that, with a flight time of one and a half
> seconds, your target's likely not going to be in the same position as he was
> when you took the shot.
>
> Now, bullet ballistics may offset this slightly by lifting the bullet in
> mid-trajectory.  You're still going to be looking at in the neighborhood of
> a ten-meter bullet drop, though, and a one-and-a-half second flight time.
>
>

there is a lovely book out there about a private enterprise attempt to "fix" the
saddam problem.  It's not a bad read but at the end of the book is a nice
chapter on the physics behind shooting at 1 km plus ranges.  If i could remember
the title i would post it but twas long ago and far away.  One of the factoids
that did strike was that you have to start worrying about the rate of spin of
the bullet as it will start to move that way.  Over a thousand meters its not an
insignificant distance couple times the width of a head i think it was.  Also
the temperature of the air can move the bullet significantly by changing the
density of the air hence the resistance.  It was a british book if memory
serves.  Anyone out there recognize it?