This has GOTTA be a stoopid question ... which is why I'm posting it here.

When I look at ballistics charts showing the trajectory of a given round, it appears that a bullet archs upward, passing the line of sight twice, once going up and once coming down.

Question: Does the bullet really arch upward, away from the ground, defying gravity, or am i misunderstanding what is meant by "line of sight"?

Why I'm asking: Gravity dictates that things go down, not up. If a bullet goes up, what phyical force is causing it to go the opposite of gravity [presuming the round is fired parallel to the ground and does that classic trajectory arch]? Also, gravity says that two objects of the same mass will fall at the same rate. So in theory if you had two identical bullets, one in your chamber and the other in your hand, and you dropped one bullet at the same moment that you fired the other from your gun [parallel to the ground], BOTH bullets are supposed to hit the ground at the same time. But, if I understand the trajectory charts correctly [and I probably don't], both bullets will not hit the ground at the same time because for a brief moment the bullet fired from the gun defied gravity and moved higher from the ground while the other bullet simply fell.

Hope I don't look too stoopid from this question ...

It *sort of* goes up then down again.

Well - not really. Gravity does work though, and it works fairly well. In fact, so well, that if you were to point the barrel EXACTLY parrallel with the ground, the bullet will probably drop down the very moment it's fully out of the muzzle. From there, it will continue down hill.

Just because guns move the bullets out of the barrel quickly, doesn't mean it's quick enough to overcome gravity. (which is pretty quick itself)

So ... if you want to hit a 50 yd (or 25 yd or 100 yd) target, you're sights will end up being set so you're actually pointing the gun up, to sort of "lob" the bullet down towards your target.

When all is said and done, gravity has the same effect on an object whether or not the object is dropped from a static height or shot from the same height; i.e., horizontal velocity does not affect bullet drop. It is true that there are some elements of "lift" involved (like a spiraling football), but that bullet does drop very quickly!

The bullet arches up because the barrel is angled slightly up. Think about shooting a gun 45° degrees up and the reason it travels upward would be obvious. Its because that's the direction you sent it.

The reason for this is, so that you can actually "zero" the rifle. Imagine a rifle barrel perfectly level and a scope on it, also perfectly level. The scope "looks" in a straight line while the bullet travels in an arch. When the bullet leaves the muzzle, it is already about 1.5 inches below the line of sight, of the scope. It will continue to drop, getting further below the line of sight. The bullet path and the line of sight will never cross and you will never shoot where crosshairs, of the scope, are pointing.

Knowing that the bullet will drop, the sights are set up so that the rifle will shoot slightly upward, so that when it starts coming back down, the bullet path and the line of sight will cross, at whatever distance it has been sighted-in at. As the trajectory tables typically will tell you there are actually two "zero" distances, where the line of sight and bullet path cross. Once on the way up and once on the way down.

Well, that makes sense. The barrel is pointing up slightly. The bullet begins to drop immediately and hits the ground just as fast as if it were dropped from your hand at the same height. Makes sense ... I guess sometimes I just take charts a bit too literally.

Hey ... I never said I knew anything about rifles I'm mostly a handgun guy and sighting-in is so simple even I can do it.

Thanks for the replies ...