Re: Shooting on an angle
Calculating a corrected “horizontal range” by multiplying the slant range distance to the target by the cosine of the elevation angle, and using this horizontal distance to determine “drop” is absolutely erroneous!
True drop at any range distance (level or slanted) is almost independent of bore elevation angle. This is because the time of flight to the given distance is almost the same, and gravity, which has the principal effect on drop, has nearly the same amount of time to act on the bullet.
True drop multiplied by [1.0 minus the cosine of the elevation angle] is very nearly the effective correction to the bullet path at any slant range from the target. This correction adds to the original bullet path relative to the reference trajectory, no matter at what distance is the gun zeroed.
BTW, this is exactly the method Michael Eichele has worked above.
BTW, try the difference between this method and the "horizontal distance" one, at long range, and you'll see the diference is huge [img]images/icons/wink.gif[/img]!!