My range finder does this for me. If I'm shooting at a 35° down angle to a target 366 yards away, it will tell me to shoot as if the target were actually at 300 yards (COS 35 X 366). I use whatever compensation is necessary for that range. If my scope is zeroed for 366 yards, obviously, it's going to shoot high at 300.
Quote from: Slippy117 on December 07, 2017, 03:23:24 PMQuote 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. ...It is a matter of perspective:portions copied from Eric's(outdoorman) diagram:The math is simple - from the shooter's perspective, drop appears be [cos(angle) x distance].Imagine that diagram where the paper target remains vertical. If the shooters measures the drop on the target, it will be the same regardless of the angle.The drop is always constant. But an angled shot will appear to hit high from the shooters perspective because the shooter overcompensated. The math is used to correct for the shooters new perspective. The actual delta-drop (drop from boreline) with respect to gravity does not change. Delta-drop with respect to gravity is determined by time of flight, not angle.
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. ...
(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
According to physics, the drop of the bullet relates to the horizontal distance it covers, in a vacuum. If the bore is level to the ground, the pellet starts dropping the instant it leaves the barrel, at the rate of 32 ft/sec**2. If the barrel is tilted upward, the pellet will rise until the vertical velocity is reduced to 0 by the force of gravity. To determine holdover, use the horizontal distance that the pellet will travel, e.g., if you are shooting at a squirrel 75' up a tree that is 75' away, then although the actual distance the pellet has to travel will be 1.414 * 75, or around 105', hold for 75' (25 yards). I've always had success by following this rule.
IMO Scott is the expert on this issue.... and I think rather than use any formulae he just practices.... AFAIK....Bob
Quote from: rsterne on December 09, 2017, 10:07:15 PMIMO Scott is the expert on this issue.... and I think rather than use any formulae he just practices.... AFAIK....BobExactly!! Forget the math and go shoot!!! A lot!!! Learn yardage, not how to read a rangefinder.
WOW! That's a lot of info.
Scot, couple of Q's...Spreadsheet formula for apex(E2) distance, based on scope-height, velocity, BC:Apex=(8000*$D$2*LN(($C$2*SQRT($A$2)/45)/7413.1/$D$2+1))Where did you get the constant of 8000 for the Apex calc?Spreadsheet formula for POI, based on zero, scope-height, velocity, BC, site-base, incline-angle: POI=(($A15-$B$2/36)*((193*POWER((34500*$D$2*(EXP($E$2/(11500*$D$2))-1)/$C$2);2)+$A$2)/$E$2)-193*POWER((34500*$D$2*(EXP(($A15-$B$2/36)/(11500*$D$2))-1)/$C$2);2)-$A$2+193*POWER((34500*$D$2*(EXP(($A15-$B$2/36)/(11500*$D$2))-1)/$C$2);2)I10*(1-COS(F$4*PI()/180)))what does POWER represent, and where did you get it? scope power? That a variable from a cell elsewhere in your calcs?and IIRC you define sight-base as the distance from the end of the scope to the muzzle...?