Posted: 3/30/2009 4:06:52 AM EDT
| Wondering where the point of impact is when your shooting up hill or down hill at 80 - 100 yards? Does the same apply to rifle, shotgun or muzzle loader? |
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You have roughly the same point of impact based on the horizontal distance regardless of the vertical. Thus, if you are shooting a target 200 yards away horizonatally, but 100 yards higher/lower than you, you have the same point of impact as if you are shooting a target at 200 yards with a level trajectory.
Anyone correct me if I'm wrong, but i think, within reasonable limits, that is true for most hunting distances. |
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Quoted: You have roughly the same point of impact based on the horizontal distance regardless of the vertical. Thus, if you are shooting a target 200 yards away horizonatally, but 100 yards higher/lower than you, you have the same point of impact as if you are shooting a target at 200 yards with a level trajectory. Anyone correct me if I'm wrong, but i think, within reasonable limits, that is true for most hunting distances. Actually, it's true regardless of distance...reasonable or not. That's why angle-compensating rangefinders have mechanisms that measure the angle from the horizontal between you and the target. Using that and the true direct distance ranged they compute the horizontal distance for you, which is your effective range for drop. |
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Quoted:
Quoted:
You have roughly the same point of impact based on the horizontal distance regardless of the vertical. Thus, if you are shooting a target 200 yards away horizonatally, but 100 yards higher/lower than you, you have the same point of impact as if you are shooting a target at 200 yards with a level trajectory. Anyone correct me if I'm wrong, but i think, within reasonable limits, that is true for most hunting distances. Actually, it's true regardless of distance...reasonable or not. That's why angle-compensating rangefinders have mechanisms that measure the angle from the horizontal between you and the target. Using that and the true direct distance ranged they compute the horizontal distance for you, which is your effective range for drop. You might be correct, but I assume that at really long distances and sharp angles, the bullet fired at a vertical angle would be travelling through more air than the horizontal bullet travelling the same lateral distance but a shorter overall distance. Thus, the angled bullet would suffer more from additonal wind resistance and drop slightly further than the horizontally-fired bullet. This is probably only an academic difference at most hunting ranges. In a perfect vaccum, say on the moon, the rule above would hold perfectly, but I think it would not hold true perfectly when firing through air, but close enough for most of us. |
| Horizontal distance is all that matters. Let's say that you are 100 yards from the foot of a 1000 yard high mountain. Now, let's assume that a mountain goat is standing on the peak of that mountain. If you are zeroed at 100 yards, you'd aim dead on. You definitely wouldn't use a 1000-yard elevation adjustment. Gravity affects the bullet on a horizontal plane. |
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Quoted: Horizontal distance is all that matters. Let's say that you are 100 yards from the foot of a 1000 yard high mountain. Now, let's assume that a mountain goat is standing on the peak of that mountain. If you are zeroed at 100 yards, you'd aim dead on. You definitely wouldn't use a 1000-yard elevation adjustment. Gravity affects the bullet on a horizontal plane. He's technically correct though, since there's more at work than just gravity (assuming you're not shooting that goat in a vacuum). Since the bullet must travel through more air along its true flight path than it would if it were fired along the horizontal axis, it's going to encounter more resistance due to drag, and lose more velocity...and therefor momentum...before reaching the target. This will ever so slightly alter the trajectory from what it would have been had it been fired in a vacuum. But at real-world shooting distances, the difference is generally negligable. |
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Quoted:
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Horizontal distance is all that matters. Let's say that you are 100 yards from the foot of a 1000 yard high mountain. Now, let's assume that a mountain goat is standing on the peak of that mountain. If you are zeroed at 100 yards, you'd aim dead on. You definitely wouldn't use a 1000-yard elevation adjustment. Gravity affects the bullet on a horizontal plane. He's technically correct though, since there's more at work than just gravity (assuming you're not shooting that goat in a vacuum). Since the bullet must travel through more air along its true flight path than it would if it were fired along the horizontal axis, it's going to encounter more resistance due to drag, and lose more velocity...and therefor momentum...before reaching the target. This will ever so slightly alter the trajectory from what it would have been had it been fired in a vacuum. But at real-world shooting distances, the difference is generally negligable. Right. Think of it this way: If you shoot a bullet level 100 yards horizontally, gravity has less than 1/10th the time to act on the bullet than if you shoot the bullet 1000 yards at a steep angle of which only 100 yards is horizontal (it is less that 1/10th instead of exactly 1/10th because the bullet is going progressively slower the last 900 yards it travels). For almost all practical shooting though, I think you can just calulate the drop based on the horizontal. But, although gravity affects the bullet on a horizontal plane, it has longer to affect the bullet in that plane the longer the distance it travels in the vertical plane, and, when air is present (on, say, earth), the additional air resistance will add up over that time and make a difference. You just won't notice that much significantly in normal situations. |