# Angle Compensation



## MuscleWhitefish (Jan 13, 2015)

Last week, I was out scouting with a bear tag in Idaho.

I spotted a decent bull that I could make a stalk on later in the year.

The group of elk that he is coming down with to feed at night, comes down a hell forsaken canyon.

I was planning at setting an ambush point away from the trail at the bottom. (I want to sit away enough not to be busted by cows, that will probably come down before the bull.)

If I do get a chance at the bull it will be 200-300 yard shot at a pretty extreme angle.

My scope has the lines 
______ 200 yd
____ 300 yd
__ 400 yd
. 500 yd

I was thinking about using a protractor and a scientific calculator to calculate the actual range.

My range finder does not have the fancy feature to calculate the actual range with respect to the angle.

If I can find the angle of the bull and use the formula 
[Measured Range x Cosine (Angle)= Range to Target].

I can come up with the range I should be aiming at to hit the bull and kill it cleanly.

As far as I researched there are only a few options for this calculation.

Cheapest - Protractor ($3) and Scientific Calculator (Owned)

Cheap - Milidot thing with a ball on a string ($40) and scientific calculator (Owned)

Expensive - Rangefinder or Binos with the angle compensation ($400+)

I am just curious if anyone else has a system that they use to compensate for the range alterations caused by topography.


----------



## nocturnalenemy (Jun 26, 2011)

won't be exact, but you could look at a contour map and estimate the difference in elevation between your sitting spot and where the elk come through. Use the rangefinder distance and the elevation difference to come up with the angle.


----------



## DallanC (Jan 13, 2009)

It wont be close, the math is pretty involved and requires the raw drop values. I worked out all of that years ago and added it as a feature in my software: dynamic angle calculation.

Software is free so I feel less guilty about linking it here.

http://huntingnut.com/index.php?name=PointBlank

There is a super simple web version I wrote that will compute the angle as well:

http://www.huntingnut.com/index.php?name=PointBlankOnline

-DallanC


----------



## MuscleWhitefish (Jan 13, 2015)

DallanC said:


> It wont be close, the math is pretty involved and requires the raw drop values. I worked out all of that years ago and added it as a feature in my software: dynamic angle calculation.
> 
> Software is free so I feel less guilty about linking it here.
> 
> ...


Thank you,

I'll have to go out and find a hill and give it a try.


----------



## 30-06-hunter (Sep 22, 2013)

How much of an angle are you looking at? Last year my spike was 236 yards across a canyon at a slight angle uphill from me and made zero changes for angle, one shot did the trick. It also helps if you zero as close as possible for the shot you expect to take, I zeroed for 200 yards due to having a 250 yard average shot where I hunt.


----------



## MuscleWhitefish (Jan 13, 2015)

30-06-hunter said:


> How much of an angle are you looking at? Last year my spike was 236 yards across a canyon at a slight angle uphill from me and made zero changes for angle, one shot did the trick. It also helps if you zero as close as possible for the shot you expect to take, I zeroed for 200 yards due to having a 250 yard average shot where I hunt.


It's from the bottom of a creek bottom onto a mountain in the river breaks.

I initially thought 60 degrees, but after reading how people grossly over-estimate angles - I would say it is somewhere between 30-45 degrees.


----------



## DallanC (Jan 13, 2009)

Fire up google earth, get the elevation difference and the distance, should be easy to compute the literal actual angle.

A certain moderator here actually requested this as a feature to PointBlank, to pull GPS locations to quickly calculate the actual angle in the field and the appropriate drop compensation... I did look into it, but it was terribly complicated trying to query information out of the different interfaces.


-DallanC


----------



## GaryFish (Sep 7, 2007)

Out to 250 yards, angle won't matter enough in most standard hunting rifles. Just "a little high" and you'll be good. ;-)


----------



## Critter (Mar 20, 2010)

GaryFish said:


> Out to 250 yards, angle won't matter enough in most standard hunting rifles. Just "a little high" and you'll be good. ;-)


Aim high and you will miss, on a steep uphill or downhill shot aim a little low. I know that there are graphs and charts and formulas to figure all this out but who has time to pull out a chart or graph when there is a animal standing out there.


----------



## MuscleWhitefish (Jan 13, 2015)

DallanC said:


> Fire up google earth, get the elevation difference and the distance, should be easy to compute the literal actual angle.
> 
> A certain moderator here actually requested this as a feature to PointBlank, to pull GPS locations to quickly calculate the actual angle in the field and the appropriate drop compensation... I did look into it, but it was terribly complicated trying to query information out of the different interfaces.
> 
> -DallanC


So, I did the google earth thing to the best of my ability.

I got 175-200 yards from where I would be sitting to the point on the mountain.

There is an 600-800 feet of elevation difference between where I would be sitting and where the elk would be ~ which is 200-266 yards.

Arc-cosine of the adjacent side over the hypotenuse.

Was what I used.

At 200 yards and 266 yards the angle would be 49

At 175 yards and 266 yards the angle would be 41.

At 200 yards and 200 yards the angle would be 0.

At 175 yards and 200 yards the angle would be 29.

I think I may just need to find a hill and shoot a bunch of rounds.


----------



## pdogger (Nov 12, 2008)

This was an interesting read.

http://www.millettsights.com/downloads/shootinguphillanddownhill.pdf

Also this might help


----------



## Mtnbeer (Jul 15, 2012)

pdogger said:


> This was an interesting read.
> 
> http://www.millettsights.com/downloads/shootinguphillanddownhill.pdf
> 
> ...


This. If you use google earth and calculate the distance on there, then that is the distance you shoot, not the distance on your rangefinder. As far as I know, google earth does not account for terrain when doing distance calculations, so whatever number you get on google earth would be the number you shoot.


----------



## shortbreath54 (Apr 23, 2009)

*high angle shots*

in either case steep up or steep down angle aim low.you are close enough for just about all modern calibers to eliminate the need for range compensation . Now just hit the big bleeders inside the target. AIM LOW in order to hit the vitals.


----------

