To those with a lot of experience with shooting at high and low angles, at what angle off horizontal do you need to factor the angle into the elevation? Do you have a rule of thumb? My vectronix rangefinder will tell me the horizontal projected distance to target but I don't use it, just absolute line of sight distance. Does the Kestrel elite read this in from the vectronix?
-
Having trouble using the site?
Contact support
shooting at high and low angles: when do you factor it in?
- Thread starter Texas T
- Start date
Advanced Marksmanship - High/Low Angle Shooting - When Do I need to worry about making an Angle Correction?
So after listening to @Cjwise5 podcast about his experience with high angle shooting, I decided to crunch a few numbers. (I like numbers) Question: When Do I need to worry about making an Angle Correction? First of all, we need to understand the amount of elevation change needed to create...
www.snipershide.com
The best way to answer your question is to generate a table with the difference in elevation correction for every hundred yards in five degree increments for your own load.
Then you'll see about how far, for a given inclination, does the difference in POI becomes too great for the targets you normally shoot.
Yeah it's not the easiest way, but it will give you the best understanding for your own rifle/load combination instead of someone else's or a generic answer.
Do you have to squint to see where youre shooting? And would you tumble down it if you happened to trip on the way there?
On a couple rifles I have a cosine indicator that gives me the value I use to determine "actual" distance.
When shooting at angles, you don't account for elevation. Gravity is a constant 9.8m/s^2 (9.8 meters per second per second) and does not change.
Picture a R triangle. The bottom of the triangle represents distance to the target, the top is you firing down an angle. Normally you'd fire straight along the hypotenuse if elevation and distance were equal. That's what you are used to.
Now we can get into all the trig OR you can just get those cosine values, make a table like has been suggested, then estimate the angle or even measure it, OR get a cosine indicator --a little wheel with numbers that rotates, attaches to rail or ring caps (I like Badger's shit personally). It changes based on angle. Once you have the cosine value, all you do is multiply it by the hypotenuse (the long side of the triangle) to get the lesser horizontal distance to the target.
Conversely, if you shoot straight down, then the trajectory is absolutely flat with no change at all.
Did that makes sense?
When shooting at angles, you don't account for elevation. Gravity is a constant 9.8m/s^2 (9.8 meters per second per second) and does not change.
Picture a R triangle. The bottom of the triangle represents distance to the target, the top is you firing down an angle. Normally you'd fire straight along the hypotenuse if elevation and distance were equal. That's what you are used to.
Now we can get into all the trig OR you can just get those cosine values, make a table like has been suggested, then estimate the angle or even measure it, OR get a cosine indicator --a little wheel with numbers that rotates, attaches to rail or ring caps (I like Badger's shit personally). It changes based on angle. Once you have the cosine value, all you do is multiply it by the hypotenuse (the long side of the triangle) to get the lesser horizontal distance to the target.
Conversely, if you shoot straight down, then the trajectory is absolutely flat with no change at all.
Did that makes sense?
Having shot a lot in mountains in Korea, Washington, Nevada, New Mexico, Utah, and Colorado you kinda-sorta become intuitive knowing when (and how much) to massage your angle compensation data. It surprised me how much density altitude velocity change there is between sea-level (San Joaquin Valley, California, and Yuma, Arizona in January-February), 4500 feet, and 10,000 feet.
That's a good idea. I seem to get a lot of insight when I look at those ballistic tables.
I want to be able to shoot anywhere from 200 to 1400 yards off tripod at all angles high and low and do it quick, so I'm looking for that feel of, say, I'm shooting down 7 degrees at 600 yards, what error am I playing with to ignore that angle. I think 308pirate nailed it, I need to study charts to get the feel I'm looking for.
Makes sense, thanks. The way I remember it from my archery days is you want the horizontally projected distance only and pretend that's the actual line of sight distance to target. If my understanding is right, then you could shoot a tall building, each floor, without ever changing holdover or elevation, it will be the same for all floors because the horizontal projection doesn't change.
Been meaning to investigate density-altitude. I've been assuming they mean air density, which is affected of course by altitude, temperature, and I guess humidity. I remember from college that air molecules are approximately 10 atomic diameters apart on average. Meaning, if a molecule is the size of a tennis ball then the next molecule is about ten tennis balls away. The atmosphere is 99 percent just two atoms that have the same diameter, nitrogen and oxygen. But I don't get how humidity variation will play into this. Since water is just one oxygen with two superlight hydrogens it doesn't make sense that humidity should make a nontrivial difference since the oxygen molecules are diatomic, two stuck together, 02, which is much heavier than a water molecule.
Understanding Pressure, Altitude and Density Altitude
Using your Kestrel to measure pressure, altitude and density altitude
kestrelinstruments.com
Hate that their site obfuscates the urls is "https://kestrelinstruments.com/understanding-pressure-altitude-and-density-altitude#"
IIRC >600M distance with >10• vertical gain is the place to start paying attention.
When you say you don't account for elevation, do you mean you don't account for altitude or do you mean you don't account for bullet drop for the distance you're shooting at?
Similar threads
Advanced Marksmanship
Where on the rifle do you measure scope height?
