Posted: 1/21/2014 9:55:08 PM EDT
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Not sure how to categorize this but, how do I calculate the distance to a target if I'm not level with the target? Say I'm fifty or so feet above the target and on a flat plane it's one hundred yards from me, would I consider this as a hundred yard shot or would I make a right triangle out of it and calculate the hypotenuse? And if so, how does that affect bullet drop?
I have some land out in CO that's on a hill, the range works fine but when I take it back to 200 I end up a ways above the target. Thx for any advice. Yes I have a good backstop. 
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Bullet path (distance) to the target determines time of flight based on speed of the projectile.
Time of projectile between muzzle and target dictates amount of drop (acceleration of gravity is a constant). If you are shooting uphill or downhill gravity is no longer acting perpendicular to path of the projectile and "drop" between muzzle and target is decreased. Therefore when shooting BOTH uphill and downhill your hits will be high for a given point of aim and target distance. The difference between shooting uphill and gravity effectively pulling your bullet back from the target and shooting downhill and gravity effectively pulling your bullet towards the target is negligible and can be disregarded. |
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Nice video. |
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I heard that shooting at an upward angle will actually put you low. Because gravity is reducing the vertical component of the bullet velocity. Nope. TrickyVic was correct about both up and down puts you high. AJE was correct in saying the horizontal distance is what counts. Both statements work together. If you range find a target on a slope and set your scope for that distance, you'll be high. If you range the target and use an inclinometer (sic) and trig out the horizontal distance, set your scope for that distance, you'll be on. Think of gravity like wind. Shooting horizontal is like a 90 degree wind. Up or down hill and the effect is reduced, same as shooting askew to the direction of the wind. |
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Nope. TrickyVic was correct about both up and down puts you high. AJE was correct in saying the horizontal distance is what counts. Both statements work together. If you range find a target on a slope and set your scope for that distance, you'll be high. If you range the target and use an inclinometer (sic) and trig out the horizontal distance, set your scope for that distance, you'll be on. Think of gravity like wind. Shooting horizontal is like a 90 degree wind. Up or down hill and the effect is reduced, same as shooting askew to the direction of the wind. Quoted:
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I heard that shooting at an upward angle will actually put you low. Because gravity is reducing the vertical component of the bullet velocity. Nope. TrickyVic was correct about both up and down puts you high. AJE was correct in saying the horizontal distance is what counts. Both statements work together. If you range find a target on a slope and set your scope for that distance, you'll be high. If you range the target and use an inclinometer (sic) and trig out the horizontal distance, set your scope for that distance, you'll be on. Think of gravity like wind. Shooting horizontal is like a 90 degree wind. Up or down hill and the effect is reduced, same as shooting askew to the direction of the wind. I know all that stuff, I guess I didn't emphasize how surprised I was to hear that longer range shots, shot at a steep upward angle will put you low. This was from one of the military snipers in one of the shows on TV. |
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I know all that stuff, I guess I didn't emphasize how surprised I was to hear that longer range shots, shot at a steep upward angle will put you low. This was from one of the military snipers in one of the shows on TV. Quoted:
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I heard that shooting at an upward angle will actually put you low. Because gravity is reducing the vertical component of the bullet velocity. Nope. TrickyVic was correct about both up and down puts you high. AJE was correct in saying the horizontal distance is what counts. Both statements work together. If you range find a target on a slope and set your scope for that distance, you'll be high. If you range the target and use an inclinometer (sic) and trig out the horizontal distance, set your scope for that distance, you'll be on. Think of gravity like wind. Shooting horizontal is like a 90 degree wind. Up or down hill and the effect is reduced, same as shooting askew to the direction of the wind. I know all that stuff, I guess I didn't emphasize how surprised I was to hear that longer range shots, shot at a steep upward angle will put you low. This was from one of the military snipers in one of the shows on TV. Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. |
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Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. |
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The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. Quoted:
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Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. The difference with which a bullet slows down going with or against gravity doesn't have nearly the affect on POI as gravity working at full force for a horizontal shot vs an inclined or declined one. I would concede that an up hill shot may be theoretically less high than the same distance/angle down hill due to gravity reducing velocity on the uphill shot. I don't know that it would be statistically measurable, though. I would be interested in seeing data on this. |
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An ad infinitum example of shooting up hill:
Shooting with your line of sight (sights line up) exactly vertical, your POI will be high because your bore axis will be past vertical. As you reduce the angle, gravity will not slow the bullet down enough to negate this effect. |
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Quoted: The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. Quoted: Quoted: Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. And if you calculate the difference in bullet velocity due to the effects of gravity, you'll find it's vanishingly small for all but the longest shots. A rifle bullet has an initial x velocity of some 3000fps. A small fraction of 32 feet/second^2 doesn't really compare.
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And if you calculate the difference in bullet velocity due to the effects of gravity, you'll find it's vanishingly small for all but the longest shots. A rifle bullet has an initial x velocity of some 3000fps. A small fraction of 32 feet/second^2 doesn't really compare. Quoted:
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Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. And if you calculate the difference in bullet velocity due to the effects of gravity, you'll find it's vanishingly small for all but the longest shots. A rifle bullet has an initial x velocity of some 3000fps. A small fraction of 32 feet/second^2 doesn't really compare. And it slows down several hundred feet per second by the time it reaches the target in many cases. A difference of a couple hundred fps in velocity can be inches difference in POI at longer ranges. Have you ever used an angle compensating range finder? You'll see that it even gives different effective horizontal distances for a given angle, based on differing projectile velocities. So it's not as simple as just using the horizontal distance when shooting at downward/upward angles. |
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Fine, I'll give you high-school level. 
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Jr. high school trigonometry. Damn, dude. What jr. high did you attend? 
o/a=t o/h=s a/h=c 
Funnest thing about trig is applying it. I get to do so every day. It's pretty cool being able to describe objects with numbers. Computers and CAD have really taken the ability to do this stuff "long hand" away from folks. Take away their puter and they're lost. 
They lose the hows and whys. That's bad. |
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Quoted: And it slows down several hundred feet per second by the time it reaches the target in many cases. A difference of a couple hundred fps in velocity can be inches difference in POI at longer ranges. Have you ever used an angle compensating range finder? You'll see that it even gives different effective horizontal distances for a given angle, based on differing projectile velocities. So it's not as simple as just using the horizontal distance when shooting at downward/upward angles. Quoted: Quoted: Quoted: Quoted: Might have been a poser who snookered the TV people. Up/Down puts you high. There is no question. The difference is that gravity is working with the vertical component of bullet velocity when shooting downward and working against the vertical component of the bullet velocity when shooting upward. And if you calculate the difference in bullet velocity due to the effects of gravity, you'll find it's vanishingly small for all but the longest shots. A rifle bullet has an initial x velocity of some 3000fps. A small fraction of 32 feet/second^2 doesn't really compare. And it slows down several hundred feet per second by the time it reaches the target in many cases. A difference of a couple hundred fps in velocity can be inches difference in POI at longer ranges. Have you ever used an angle compensating range finder? You'll see that it even gives different effective horizontal distances for a given angle, based on differing projectile velocities. So it's not as simple as just using the horizontal distance when shooting at downward/upward angles. And you'll never get that in practice. cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories.
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cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. |
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Pretty good write up on angle shooting.
For all practical purposes at any distance that most folks will shoot, at which targets they need to hit, the "horizontal distance" is close enough. http://www.longrangehunting.com/articles/angle-shooting.php |
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Pythagorean Theorem I used this the other day at work to figure a roof beam length. Now all of my employees think I'm a fucking wizard. I've been a contractor all of my life and I don't think I've ever gained more respect at one time than I did using that theorem one time.
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You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. Quoted:
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cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. I never got to study projectile physics in high school. And I didn't get trig in jr. high. I'm starting to feel that my private school education was substandard.
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Quoted: You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. Quoted: Quoted: cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. |
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I used this the other day at work to figure a roof beam length. Now all of my employees think I'm a fucking wizard. I've been a contractor all of my life and I don't think I've ever gained more respect at one time than I did using that theorem one time.
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Pythagorean Theorem I used this the other day at work to figure a roof beam length. Now all of my employees think I'm a fucking wizard. I've been a contractor all of my life and I don't think I've ever gained more respect at one time than I did using that theorem one time.
Show 'em the 3,4,5 triangle square method and you'll be golden.
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I never got to study projectile physics in high school. And I didn't get trig in jr. high. I'm starting to feel that my private school education was substandard. Quoted:
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cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. I never got to study projectile physics in high school. And I didn't get trig in jr. high. I'm starting to feel that my private school education was substandard. I was exaggerating, much like when AR4U said Jr. High trig. Second semester of Classical Physics 201 is more like it. 
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Damn, dude. What jr. high did you attend?
o/a=t o/h=s a/h=c Quoted:
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Jr. high school trigonometry. Damn, dude. What jr. high did you attend?
o/a=t o/h=s a/h=c It's easier to remember if you say, "SOHCAHTOA". I've even seen a nerd wearing a shirt that said, "Camp Sohcatoa" as though it were a summer retreat. |
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It's easier to remember if you say, "SOHCAHTOA". I've even seen a nerd wearing a shirt that said, "Camp Sohcatoa" as though it were a summer retreat. Quoted:
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Jr. high school trigonometry. Damn, dude. What jr. high did you attend?
o/a=t o/h=s a/h=c It's easier to remember if you say, "SOHCAHTOA". I've even seen a nerd wearing a shirt that said, "Camp Sohcatoa" as though it were a summer retreat. Yeah. My old boss had some English thing about "small curly headed" something or nuther. I use the stuff enough that I can work around a triangle just about anyway you care to name. Right, obtuse, acute, etc.
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Go on... Quoted:
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cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. Shoot upwards at a given angle and distance, then shoot an equivalent downward angle and distance and you will see that the upward shot impacted the target lower than the downward shot. How much that difference is depends on angle and bullet velocity, but it is a difference and could make all the difference. It's not as simple as applying the horizontal distance to all upward/downward shots and bullet velocities and expecting the same results. |
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As an example, plug in the data for a 155 scenar from a 308 at 1000 yards at sea level. The difference between -45 and 45 degrees is one scope click. Those are for extreme angles near the end of the effective range of the round. Realistically the differences in atmospheric pressure along the bullet's path would make a bigger difference. |
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Shoot upwards at a given angle and distance, then shoot an equivalent downward angle and distance and you will see that the upward shot impacted the target lower than the downward shot. How much that difference is depends on angle and bullet velocity, but it is a difference and could make all the difference. It's not as simple as applying the horizontal distance to all upward/downward shots and bullet velocities and expecting the same results. Quoted:
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cos(theta) * 32FPS^2 times the flight time is going to be negligible unless you start using artillery trajectories. You don't have to review high school projectile physics with me. I used to think projectiles behaved the same way you all are describing. Shoot upwards at a given angle and distance, then shoot an equivalent downward angle and distance and you will see that the upward shot impacted the target lower than the downward shot. How much that difference is depends on angle and bullet velocity, but it is a difference and could make all the difference. It's not as simple as applying the horizontal distance to all upward/downward shots and bullet velocities and expecting the same results. I'll agree that there is a difference in the amount of moa of higher poi between uphill and down hill shots. I will also say that the difference is negligible for all practical purposes. |