Talk:Point-blank range

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[edit] deviation

"If the sights are lower than the allowable deviation..."

What is meant by high and low sights? If a scope on your varmint rifle is 2 inches above the barrel and parallel to the barrel then the bullet should hit two inches below your cross hairs at short distances. Is the sight 2 inches high in this case? If the sight was 1 inch above the barrel then your range would be greater? --Gbleem 14:50, 22 September 2006 (UTC)

To visualize this, assume we have a perfectly horizontal line of sight through the sights at the target, and assume the bullet follows a parabolic arc--the true path will be somewhat squished due to air resistance, but a parabola is close enough for this though experiment.

Now if we only care about sighting in for one exact range, then we can alter than flatness of the parabola as needed, by tilting the barrel, until the parabola crosses the light of sight at any desired point within the maximum range of the bullet. For short ranges, it would be easiest to cross the line of sight on the rise, for long ranges, on the fall.

Let's assume we have a case where, if the sights are eactly level with the muzzle, we cross the line of sight at 0 and 100 meters, and our midrange trajectory is 10 cm above the line of sight. If we're shooting, say, prarie dogs, that 10 cm midrange trajectory means that we're going to miss high when aiming at prarie dogs that are about 50 m distant, even though we can hit the close ones and the far ones. If we change the angle of the barrel, then we can drop our midrange trajectory, but we also cut down our maximum range, because the bullet is going to drop below the line of sight far sooner than it was with the high mid-range trajectory.

So what we need to do to ensure that we can hit the prarie dogs anywhere from 0 to 100 meters is to keep the curve to our trajectory, but move the line of sight so that our midrange trajectory is less high relative to the line of sight. By raising the line of sight by 5 cm, we are now going to hit 5 cm low at 0 m, 5 cm high at 50 m, and 5 cm low at 100 m. Now, if it is the case that a prarie dog sticks its head out of its hole about 10 cm worth, then aming at the middle of the prarie dog will get us a hit at any range from 0 to 100 meters.

Since generally shots aren't going to be taken at very close ranges, it's actually advantageous to set your sights higher than the target radius, so that you can push the midrange trajectory out as far as possible, because that's the limiting factor in maximizing the point blank range. However, most people find high sights unattractive and awkard to use, so low sights are probably here to stay. scot 15:31, 22 September 2006 (UTC)

[edit] Everyday usage - a classic cliché

I'm pleased to find that the phrase "point-blank range" has such a technical explanation. For a long time, I've regarded it as the worst cliché in the English language - and in its everyday (mis)usage, I do not resile from that opinion.

In this connexion, I note Eric Partridge's description of a cliché: "a coin so defaced by usage as to have lost all value" ... Hair Commodore 20:56, 8 November 2006 (UTC)