Shooting uphill

Don't think it's extreme enough to matter.

Any elevation angle (up or down) will impact higher than a level shot. At 25 yards the amount will be very small.

Does it effect? - Yes.

Is it enough for you to care too much? - Nope.


Todd.

deadeye dick said:

Please don't laugh.

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I'm not laughing... I'm gritting my teeth in envy - Sure wish I could shoot in my back yard!
Well , I guess I could , but only for a very short time , then things would get real interesting real fast.

As far as the grade change is concerned , I've always found it easier to be on target shooting downhill as opposed to uphill. Just me? Don't know.

While there will be a very slight change in PoI because of the elevation, I see a much bigger problem with shooting uphill.
Where does the bullet go if you miss?? And what is beyond your target?

JTHunter said:

While there will be a very slight change in PoI because of the elevation, I see a much bigger problem with shooting uphill.
Where does the bullet go if you miss?? And what is beyond your target?

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Hopefully, more hill?

Darn good point though.

Todd.

Waveski said:

I'm not laughing... I'm gritting my teeth in envy - Sure wish I could shoot in my back yard!
Well , I guess I could , but only for a very short time , then things would get real interesting real fast.

As far as the grade change is concerned , I've always found it easier to be on target shooting downhill as opposed to uphill. Just me? Don't know.

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Down hill is less of a fight with gravity. Even shooting uphill you really would have to be shooting pretty steep and far. IMO the most challenging is up, down or straight across descending terrains. It's more difficult to judge the straight line range.

Unless you are doing long range precision shooting, it probably won't make much practical difference.

skeeterfogger said:

Down hill is less of a fight with gravity. Even shooting uphill you really would have to be shooting pretty steep and far. IMO the most challenging is up, down or straight across descending terrains. It's more difficult to judge the straight line range.

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Up and downhill are the same - we account for angle regardless of whether up or down, by accounting for only the horizontal component of travel. Gravity only works perpendicularly to the surface (radially to our center of mass), so it’s considered a Normal force, meaning it only and always acts downward. Resultingly, shooting uphill or down, the result is the same, your POI will be higher than your line of sight range would suggest.

6-8ft rise with a 25 yard line of sight, call it 2-3yrds over 25, is 4.6-6.9 degrees, giving 24.82-24.92yrds of horizontal. Not enough for anyone to bother correcting even an archery shot, let alone a rifle.

Any laser rangefinder should have the ability to output line of sight or angle corrected range - the horizontal component which affects your drop.

deadeye dick said:

The question is it's up hill. at 25 yds. it rises about 6 to 8 feet. Will this effect POI at the target.

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Yes if shooting an iron sight handgun. When shooting at a Precision Pistol/Bullseye Pistol 25 yard target, the bullet impact may move out of the X ring, if sighted in on a flat range, using a 6 o'clock hold . It will hit higher.
Its not the distance, its the upward angle. Its how the target appears in correlation with iron sights. Hard to explain.

If your not facing the target straight on, target off to the left, bullet impact will be left. Same , but reversed if off to the right.

The black bulleseye will appear to be different in size between bright sun & cloudy over cast . More so at 50 yards. A slight sight adjustment is needed. Sun on target, groups move lower, because bullseye appears larger.

It only matters if trying to place shots in the X ring at Precision Pistol/Bullseye Pistol competitions.

Varminterror said:

Up and downhill are the same - we account for angle regardless of whether up or down, by accounting for only the horizontal component of travel. Gravity only works perpendicularly to the surface (radially to our center of mass), so it’s considered a Normal force, meaning it only and always acts downward. Resultingly, shooting uphill or down, the result is the same, your POI will be higher than your line of sight range would suggest.

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deadeye dick said:

The backstop (dirt pile) is 6 feet above my targets. Beyond that the ground continues to rise for another 25 yds. to my property line. Beyond that is 90 acres of brush and trees. I only shoot handguns. It's like being on the moon.

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Ever since I outgrew shooting bottles for not wanting to litter the countryside with glass and stopped shooting cans since the aluminum ones last forever and the steel-tin of my youth disappeared in a year or two... shooting dirt-clods and rocks down a hillside has become my favorite *pliinking* activity.

I envy you, your little slice of heaven.

Todd.

Isn't there an old saying about shots aimed uphill tend to go low and shots aimed downhill tend to go high?

MI2600 said:

Isn't there an old saying about shots aimed uphill tend to go low and shots aimed downhill tend to go high?

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If there was, it’s wrong about the uphill shots.

Shooting uphill or downhill, aim below the target.

“Objects at angles are closer than they appear.”

Varminterror said:

Up and downhill are the same - we account for angle regardless of whether up or down, by accounting for only the horizontal component of travel. Gravity only works perpendicularly to the surface (radially to our center of mass), so it’s considered a Normal force, meaning it only and always acts downward. Resultingly, shooting uphill or down, the result is the same, your POI will be higher than your line of sight range would suggest.

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If this is difficult to intuitively grasp, here's an easy thought experiment that will help you "get" why downhill and uphill shots "drop" less than level shots.

• First, imagine a barrel pointing straight down at the ground while hanging in mid-air 100 yards above the earth. How much will gravity cause the bullet to deviate from its start direction (0° down)? None, right? Just a straight line into the ground (leaving aside wind).
• Second, imagine rotating that gun to point straight up. Again, how much will gravity cause the bullet to deviate from it's start direction (180° up)? Again, none, right? The bullet will lose velocity faster as it works against gravity, but it won't curve... it will just go straight up until its velocity reaches zero. And then it will fall straight back down (ignoring the aerodynamic effects of tipping in one random direction at the apex).
• Third, imagine the gun rotating to shoot parallel to the earth's surface, 90° off of gravity's pull. How much will the shot deviate from its start direction? It will deviate downward at 32 ft per second per second.... gravity will pull it off its initial start line.

Uphill and downhill shots are a combination of one of the first two scenarios and the last scenario. Shooting 10° uphill is 80/90ths (89%) horizontal, and 10/80ths (11%) straight up. Only the sideways portion of each shot gets deviated by gravity... so that 11% uphill on a 10° shot doesn't get pulled down by gravity.

Now, shooting uphill or downhill will have different results in terms of velocity of the bullet at impact.

ATLDave said:

Only the sideways portion of each shot gets deviated by gravity

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I get what you’re trying to say here, but it’s backwards of the actual vector science we’re talking about - gravity only works in the vertical, so only the vertical component of the shot is influenced. The only force acting in the “sideways” vector once the bullet leaves the muzzle is air drag, gravity is ONLY acting in the vertical.

Varminterror said:

I get what you’re trying to say here, but it’s backwards of the actual vector science we’re talking about - gravity only works in the vertical, so only the vertical component of the shot is influenced. The only force acting in the “sideways” vector once the bullet leaves the muzzle is air drag, gravity is ONLY acting in the vertical.

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Yeah, we're both saying the same thing. I get that I'm using terminology that is wrong from a real engineering perspective. I'm just trying to phrase it in a way that may be intuitive to those people who struggle to grasp your (excellent and more technically correct) explanation.

TO BE CLEAR: If anyone perceives there to be some conflict between my explanation and Varmint''s post #10, go with Varmint's post.

At that range not enough to matter. But at longer ranges and greater differences in height it can make a difference. Not really saying anything others haven't said, just providing a visual.


This is a good illustration why. This is showing the target lower than the shooter and with a bow, but the same principle applies shooting up as well as down and with a rifle/pistol as well as a bow. In this case the bow hunter is 20 yards above the ram. Straight line of sight to the ram is 30 yards, but in reality the arrow (or bullet) only travels 21 horizontal yards. It would be the same if the hunter were 20 yards below the ram.

If the bow hunter calculates the distance to the deer as 30 yards in this example his arrow will drop less than expected since the ram is actually only 21 horizontal yards away. If this were a rifle, or handgun hunter the difference between 21 and 30 yards isn't enough to matter. For a bow hunter it is.

But suppose we multiply all numbers by 10 and give our hunter a rifle. The hunter is now on a hill 200 yards above the ram which his range finder says is 300 yards away. But because of the angle the ram is only 210 horizontal yards from the hunter. If our hunter takes his shot figuring on a 300 yard shot he will hit high and probably miss the ram.

Once again it works the same shooting up as it does down. The target will be closer horizontally than it appears.

If the Hunter in @jmr40’s graphic above is shooting 20yrds uphill instead of downhill with the same 30yrd LOS, flipping that graphic upside down, we see the same reduction in horizontal range. So shooting a 30yrd LOS 20yrds above or below is the same as a 21yrd shot.

I penciled out some of the geometric vector math for the velocity influence yesterday reflecting @ATLDave’s comments re: uphill vs. downhill influence of gravity on the impact velocity, I should be able to push that through with some real numbers this afternoon or tomorrow to offer a specific example.

deadeye dick said:

Please don't laugh. This may sound silly but I'm a very curious person and know nothing about physics. I shoot in my yard. I have a 25 yard clearing and a large pile of dirt as a backstop. The question is it's up hill. at 25 yds. it rises about 6 to 8 feet. Will this effect POI at the target.

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The best way to out is to go shooting and see the results for yourself. With your chosen ammo and gun. In your backyard and, when you can, up and down steeper and higher actual hills.