Quote from: Wolverineshooter on December 04, 2017, 09:44:33 AMI read many website on this issue and have difficult understanding it, at least it is contradictory to my intuition.First my intuitive understanding. I assume no drag to simplify the arguments. Then the horizontal pellet traveling distance is (direct distance)*cos(line of sight angle relative to horizontal), horizontal speed will be (muzzle speed)*cos(line of sight angle+barrel to line of sight angle), and calculations can be done based on this. My calculations show that when not shooting flat, there is more drop from the line of sight.But pretty much all websites are now saying that the pellet will hit higher when shooting at angles. The explanation involves arguing that the drag only works horizontally, but not vertically. That does not make any sense to me.Let me know your experiences and thinking. ThanksIt's not the drag, it's the angle of the shot vs. the direction of the pull of gravity.
I read many website on this issue and have difficult understanding it, at least it is contradictory to my intuition.First my intuitive understanding. I assume no drag to simplify the arguments. Then the horizontal pellet traveling distance is (direct distance)*cos(line of sight angle relative to horizontal), horizontal speed will be (muzzle speed)*cos(line of sight angle+barrel to line of sight angle), and calculations can be done based on this. My calculations show that when not shooting flat, there is more drop from the line of sight.But pretty much all websites are now saying that the pellet will hit higher when shooting at angles. The explanation involves arguing that the drag only works horizontally, but not vertically. That does not make any sense to me.Let me know your experiences and thinking. Thanks
What often helps me with a concept like this is looking at the extreme example, and then connecting the dots in between. In this case, what happens if you were to shoot straight up into the sky. So here are just a few points leading up to it: 1. The pellet is always falling from the instant it leaves the muzzle.2. The scope is adjusted to meet with the falling pellet at X yards. That is, the scope is pointing down so the crosshairs (line of sight) intersect the falling pellet out at some distance. The result is that the pellet apparently "rises" to meet the scope's line of sight, and then falls away again in the distance.3. If you were to aim straight up into the air (90° incline), the pellet will "rise" and cross the scope's line of sight and continue on in that direction (above the crosshair, or in this case behind you), and it will never cross back over because gravity cannot push it back in that direction.4. So basically, the pellet always "rises" to meet the line of sight. How quickly (how close to the muzzle) it does that depends on how much gravity is acting on it. If shooting horizontally, gravity has its maximum influence. If shooting vertically, gravity has (almost) no influence. Meaning as you swing from more horizontal to more vertical, gravity has less and less influence and the pellet will "rise" over the crosshair sooner and at a steeper angle, thus shots will land higher.5. At very close distances, you still have to use holdover because the pellet needs some minimum distance to climb up to the crosshair. I'll have to work on making this more concise
An inclined shot always drops less than a horizontal shot. Gravity only acts on the horizontal distance. So the drop amount would be the same as it would be for the distance we get by multiplying the line of sight distance by the cosine of the incline angle.Where some people make the mistake is thinking that after doing the cosine math, they can use the calculated horizontal distance to look up the the holdover on their dope. You can get away with it for very very long shots, but not for close shots. For close shots, holdover is being used to compensate for the height of the scope, with very little caused by drop. As you get inside your zero, hold increases as distance decreases - just the opposite of what happens with drop.For close shots, you must subtract the delta-drop from your holdover dope for the line of site distance. Fortunately, most very close shots have very little drop to contend with. So, unless the target is very tiny and angle extreme, you can ignore it or just hold down a smidge.
If you are shooting up or down, aim low.
When you are zeroing with a flat/horizontal trajectory, the FULL gravity effect is maximum. Then, you have zeroed when the FULL gravity WAS pulling down the trajectory. When shooting up.. Due the angle, PART of the gravity is not pulling the trajectory down, but slowing a bit the fps. When shooting down .. due the angle, PART of the gravity is not pulling down the trajectory, but increasing a bit the fps. In both angled cases, as you don’t have the full gravity pulling down the trajectory, the POI is going to be a bit up (than you have zeroed), and you have to aim a bit lower.
Good video. Wonder what my nabour will think if I start shooting his pine tree on his front lawn? LOL
Marcos, gravity always works the same regardless of the angle - it just pulls the pellet down at 9.8meters/second^2 acceleration.
Quote from: Wolverineshooter on December 05, 2017, 12:23:09 AMMarcos, gravity always works the same regardless of the angle - it just pulls the pellet down at 9.8meters/second^2 acceleration. I disagree. When you shoot perfectly horizontal, the pellet starts dropping the instant it leaves the barrel. That is not the case when shooting at an upward angle. The velocity and mass of the projectile is working against the force of gravity. Eventually, it loses the battle and then the pellet starts dropping.
Yes that is correct. When viewed from the barrel angle relative to ground, the effect of the initial velocity is cancelled and the gravity does all the pulling, the same way s if you are shooting flat
Quote from: Scotchmo on December 04, 2017, 05:31:13 PMAn inclined shot always drops less than a horizontal shot. Gravity only acts on the horizontal distance. So the drop amount would be the same as it would be for the distance we get by multiplying the line of sight distance by the cosine of the incline angle.Where some people make the mistake is thinking that after doing the cosine math, they can use the calculated horizontal distance to look up the the holdover on their dope. You can get away with it for very very long shots, but not for close shots. For close shots, holdover is being used to compensate for the height of the scope, with very little caused by drop. As you get inside your zero, hold increases as distance decreases - just the opposite of what happens with drop.For close shots, you must subtract the delta-drop from your holdover dope for the line of site distance. Fortunately, most very close shots have very little drop to contend with. So, unless the target is very tiny and angle extreme, you can ignore it or just hold down a smidge.Scott, the gravity only affects vertical speed, so if we do not consider the drag the pellet traveling time will be nearly the same regardless of the incline. So the drop will be nearly the same from the line of shooting, but may change slightly more from the line of sight.
(Greg) Wolverineshooter,It's a matter of perspective. From the targets perspective, the drop is the same regardless of the angle that the projectiles comes from. From the shooters perspective, the drop appears to be less, so he uses less compensation.Say that you have a flat paper target standing upright down range. Say the bore-line is pointed at the middle of the paper. A shot from 100 yards away might hit 5" low. It does not matter what the angle is. If it's comes in horizontally from 100 yards away, it hits 5" low on the paper. If it comes in from a 45 degree incline and 100 yards away, it still hits 5" low on the paper. That is from the targets perspective.From the shooter's perspective, it is 5" low when viewed on the horizontal. But when the shooter views it from a 45 degree incline, the POI appears to be (cos45 x 5"), or 3.54" low. However, when the shooter goes up to the target to measure the POI using a caliper, it really is 5" low.Without compensation, the POI would be the same regardless of the angle. What matters is the amount of compensation, relative to the the shooter, not relative to the target.The amount of drop relative to the target will always be based on time of flight. On an inclined shot, the shooter's perspective is what is changing, hence different amounts of compensation (from the shooter's perspective).
Quote from: Slippy117 on January 26, 2018, 11:30:51 AM The pellet perfectly finds its mark Nutter falls and proceeded to leave this world with the death dance as a final celebration To headshot or not to headshot, that is the question This is pure poetry![quote author=Slippy117
The pellet perfectly finds its mark Nutter falls and proceeded to leave this world with the death dance as a final celebration To headshot or not to headshot, that is the question
Quote from: Scotchmo on December 07, 2017, 02:35:24 PM(Greg) Wolverineshooter,It's a matter of perspective. From the targets perspective, the drop is the same regardless of the angle that the projectiles comes from. From the shooters perspective, the drop appears to be less, so he uses less compensation.Say that you have a flat paper target standing upright down range. Say the bore-line is pointed at the middle of the paper. A shot from 100 yards away might hit 5" low. It does not matter what the angle is. If it's comes in horizontally from 100 yards away, it hits 5" low on the paper. If it comes in from a 45 degree incline and 100 yards away, it still hits 5" low on the paper. That is from the targets perspective.From the shooter's perspective, it is 5" low when viewed on the horizontal. But when the shooter views it from a 45 degree incline, the POI appears to be (cos45 x 5"), or 3.54" low. However, when the shooter goes up to the target to measure the POI using a caliper, it really is 5" low.Without compensation, the POI would be the same regardless of the angle. What matters is the amount of compensation, relative to the the shooter, not relative to the target.The amount of drop relative to the target will always be based on time of flight. On an inclined shot, the shooter's perspective is what is changing, hence different amounts of compensation (from the shooter's perspective). its not a matter of perspective. If you are zeroed @ 50yards while horizontal, your projectile will hit bullseye @ 50 yards while horizontal. If you take the same exact rifle that is zeroed at 50 yrds horizontal, and aim at a target 50 yrds away perfectly vertical. You will not hit bullseye, your projectile will hit high on anything slightly less than your first zero or further. Its that simple. Its all about figuring the distance that the projectile is traveling that gravity has an effect on it, well atleast its relative effective force. Im sure there is some complex math that you can put behind it. But the general physics behind it are relatively simple. ...