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Discussion Starter #1
I was wandering, why when shooting downhill or uphill a rifle tends to shoot high?
 

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Discussion Starter #3
But why? Does it have something to do with a visual effect resulting from the angle or is this because the trajectory changes?
 

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Think of it this way: If you shoot straight up, gravity slows a bullet down, but does not change its trajectory. The bullet goes straight up and straight down, theoretically. The closer to straight up you're shooting, the less of an effect gravity has on trajectory, thus requiring you to aim lower than you would otherwise.
 

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Isaak Newton is to blame :)
His excuse is that an apple fell on his head... Now we have to aim a little bit high when shooting uphill or downhill.
 

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exterior ballistics

A good read on this subject and its practical applications.
Jeez, never mind practical. If we were practical, we wouldn't own at least 3 guns in every caliber from .17 to .500. What's fun is ignorant thinking about it. For instance, shooting downhill ought to help the bullet maintain velocity, while uphill should make it slow down quicker. That affects trajectory how? No looking it up, make a 'logical' guess.

:p
 

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Jeez, never mind practical. If we were practical, we wouldn't own at least 3 guns in every caliber from .17 to .500. What's fun is ignorant thinking about it. For instance, shooting downhill ought to help the bullet maintain velocity, while uphill should make it slow down quicker. That affects trajectory how? No looking it up, make a 'logical' guess.

:p
The net difference in bullet velocity between bullets shot on an incline or decline is not enough to cause noteworthy changes in POI, at reasonable distances.

The difference between the two is particularly insignificant when compared to the velocity lost to drag.
 

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VThillman, might be best to think about this "issue" keeping two things in mind; One is that if your shots, whether steep uphill or steep downhill are not any farther than your MPBR, then there is zero issue. Secondly, if the steep angle of the shot means that the bullet's travel through the body of the beast makes a difference, then aim accordingly. IE, if shooting at a moose on a steep downward angle at 100 yards, I'd not try for a low heart shot as the bullet's travel through the body at that steep downward angle could make you miss the heart, or just barely touch it.
 

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The net difference in bullet velocity between bullets shot on an incline or decline is not enough to cause noteworthy changes in POI, at reasonable distances.

The difference between the two is particularly insignificant when compared to the velocity lost to drag.
Well OK; but the difference is there, and that's the important thing philosophically.

:cool:
 

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Yes!

This ^^^^^.
+1
It has to do with geometry.
 

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shooting uphill or down.

it has nothing to do w gravity or bullet weight or speed. its simple trigonometry. not geometry. rule...when shooting up or downhill always always hold low. reason... the hozontal distance is closer. the hypotenuse is longer than the adjacent side. thats called the cosine. its a percentage. as the angle increases the horizontal distance decreases by a percentage. hope that helps. roofers and stsir builders use the same formula.
 

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I believe one has to aim low, not high, when shooting either uphill or downhill.

The details are great for those with a passion for engineering (if you want detail in metallurgy I can tell you far more than you really want to know about the barrel on your favorite shotgun or muzzle loader)

High or low is all that matters to most of us.
 

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Draw yourself a triangle. To help with the visualization draw it with the horizontal and versicle sides equal (right triangle)

Shooting up or down hill you are shooting the hypotenuse => long side.

Drop is gravity on the side parallel to earth => base side. Up hill or down doesn't male a difference.

To carry it to absurdity make the vertical straight up => horizontal = 0, The hypotenuse is the max vertical yards of your load. Lots of yards. Bullet drop is zero it hits exactly on the end of your barrel where it left.
 

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The apparent bullet drop is measured perpendicular to your line of sight. If you are shooting at an angle from horizontal gravity is pulling at an angle to this vector which lessens the real drop. At a 45 degree angle gravity only has 70 % of its normal effect.

To see it at work get a board or stick. It doesn't matter how long. Hang a weight on a string from the board. Hold the board at an angle and measure the perdendicular distance from the weight to the board. The length of the string is the same just as the true drop of the bullet is the same. The distance from the board to the weight will be the apparent bullet drop. The steeper the angle of the board the closer the weight will be.
 

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It is not geometry, it is physics. A bullet receives its maximum deflection from gravity when traveling horizontally. As stated earlier, there is no deflection when shot straight up, or straight down for that matter. The closer to horizontal, the greater the deflection. To visualize this, take a limber fishing rod and hold it horizontal and see how much it bends, then slowly raise it and watch how it begins to straighten out. It is the horizontal distance the bullet travels that determines the amount of deflection. To visualize how a bullet drops, think of a fly ball in baseball. It starts out on what appears to be a straight line then curves downward at an ever increasing rate. In the first second it drops 16 feet below the line of launch, but 48 feet in the second second due to the acceleration caused by gravity. So does a bullet. It just travels further during that time. This is why even bullets from magnums drop like crazy after 300 yards.
 
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