Angle Shooting - Correcting For The Effects Of Gravity by Ward Brien

[Len Backus]

Think of the direction of gravity towards the center of the earth. As the target angle changes, the angle of gravity stays the same. Less of gravity's force comes into play. I agree that time stays the same but the gravity VECTOR (fancy first year college physics term) changes relative to the angle of the shot.

Gotta go bowhunting now....

[MontanaRifleman]

Jaceduece, Like Len said it's the *vector* (direction) of the force of gravity that is changing (in relation to the bullet's path, not the Earth) when changing shooting angle. The force of the gravity IS the same over the same period of time. But the percieved affect (drop) is different becausse that effect is no longer perpendicular to the bullet's path.

To take it to an extreme, if you shot a bullet straight up, there would be no percieved drop at all, because the bullet hasn't traveled over ground at all. But... gravity has still had an affect on the bullet. The more you increase the angle up (or down) the less the *percieved* effect in relation to the level ground because less level ground has been covered in the same amount of time. Now, imagine the shot that is almost straight up, say 80 degrees, still almost no percieved drop, but gravity is still working. The more you angle your shot toward the earth, the more you see the results fo the gravity pulling the bullet down from it's path.

Hope that's clear as mud.

[Marine sniper]

Also consider when shooting uphill v. downhill, that gravity has far less effect on the bullet than drag (resistance to air) so while gravity may pull a little harder on a bullet going uphill it is negated by the effect of drag.

[jwp475]

Originally Posted by Marine sniper

Also consider when shooting uphill v. downhill, that gravity has far less effect on the bullet than drag (resistance to air) so while gravity may pull a little harder on a bullet going uphill it is negated by the effect of drag.

Exactly. There is much more to than just gravity

[deepandsilence]

.308 Tactical (Custom Built) : Bolt Action at GunBroker.com
Check out my rig, I got one of those angle finders from Night Force and I am thankful for it. 617 yards one shot cold bore hit down hill almost at 45 degrees.
Target milk jug.
Mission accomplished.
I use Eskimo for ballistic calculations and weather channel for data.
Works just fine!
deepandsilence

[eshell]

Great article Ward!

I have several (5) of these ACI's on my various competition and hunting rifles and have been VERY pleased with both the device itself and with Ward's first class customer service. I damaged one myself and could not have asked for a faster or more generous solution than that offered by Sniper Tools.

[japhunter]

I have been having trouble matching ballistic software results to the real tradjectory measured . I am in the proccess of going througn the many obvious varailbles but i am now wondering weather there is some correction for having a 20 moa one picatiny rail that i should be making ?
Regrds Jap Hunter NZ