# Thread: Shooting Up or Down Hill - why aim low?

1. ## Shooting Up or Down Hill - why aim low?

Could someone please explain in relatively simple terms why you need to aim low when shooting up or down hill.

2. Sometimes if you take a problem to extremes it's easier to work out what's going on.
Imagine shooting vertically up. You wouldn't have to aim off no matter what the range 'cos gravity wouldn't be dragging the bullet off course. Same if you shot vertically down.
Hope that makes sense.

3. because shooting over a flat plain gives a slight arc trajectory,,,, uphill or downhill its a very slightly different trajectory to your flat one

4. +1 gravity-1

5. Basically you will have zero'd your rifle shooting in a horizontal plain. You know your bullet drops from the moment it leaves the barrel due to gravity pulling it down, so will gradually fall to the ground. Now if you aimed higher your bullet would travel further as you will have used the bullets energy to counter gravity and your bullet will go further. So if shooting down hill your are in effect using gravity, or fighting it to a lesser extent so "drop from horizontal zero" will be less and therefore you need to aim lower than if shooting at a horizontal target. Same applies for shooting up hill as again gravity will take a slower effect on something travelling above horizontal (until energy is lost, then it will drop like a stone).

Best thing is sit on a hill and shoot something at the bottom see what your "drop" is.
Good question though. Hope that was simple enough?

6. Originally Posted by daw
Could someone please explain in relatively simple terms why you need to aim low when shooting up or down hill.
The range that impacts on the bullet flight is the horizontal range to the target. One of my favourite writers gives a slightly wordier explanation.

http://www.chuckhawks.com/shooting_uphill.htm

Regards JCS

7. Originally Posted by private fraser
Sometimes if you take a problem to extremes it's easier to work out what's going on.
Imagine shooting vertically up. You wouldn't have to aim off no matter what the range 'cos gravity wouldn't be dragging the bullet off course. Same if you shot vertically down.
Hope that makes sense.
It does up to a point, but if you measure gravity accurately, it doesn't always pull straight down - ask the folk who launch ICBMs. It varies as well.

gravity map of the uk - Google Search

Regards

JCS

8. Because the horizontal distance to the target is less than the line of sight distance

9. Originally Posted by AN DU RU FOX
because shooting over a flat plain gives a slight arc trajectory,,,, uphill or downhill its a very slightly different trajectory to your flat one
Absolute rubbish. The bullet is always dropping from the time it leaves the muzzle. At no time does it rise in an arc.
The arc you see on the ballistic charts is because of the point of aim being higher.

10. Have a watch of this, there are others that offer an insight to what has already been mentioned regarding bullet path & bullet trajectory, distance to target and line of sight distance being fractionally different.

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