Shooting Up or Down Hill - why aim low?

[Dorsettaff]

Do you know, reading this lot I bet Stephen Hawking is sh*tting himself in case you lot come up with a new grand unified theory!

I think MS puts it into perspective...think of the path of the bullet as it hits the deer. I think some of us have been reading too many American websites where everyone shoots quarry at 1 mile from up or down a 45 degree cliff!

 

[Monkey Spanker]

Google "Slope Doper" (Dope the Slope, Elk Hunt, Mil Dot, Range Finder, DP Rolls)

Ian

Great theory, but you still have to adjust the point of aim on the animal to hit the vital organs. I think the 'slope doper' rates quite highly in the rankings of 'useless kit' that you can carry, probably somewhere in between a 'Butt-Out' tool and a 'Cough Muffler'! Which reminds me..... I must sort out the patent on my latest design of fart suppressor.
MS

 

[private fraser]

No sign of the opening poster.
Think I heard a scream then someone running.
Maybe there weren't enough answers.

 

[JTO]

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

+1

 

[Bez]

Do you know, reading this lot I bet Stephen Hawking is sh*tting himself in case you lot come up with a new grand unified theory!

I think MS puts it into perspective...think of the path of the bullet as it hits the deer. I think some of us have been reading too many American websites where everyone shoots quarry at 1 mile from up or down a 45 degree cliff!

Agreed was trawling youtube the other day and saw some 10yr old kid shooting an elk at something like 1000 yards across a valley. Madness

 

[Yorric]

Great theory, but you still have to adjust the point of aim on the animal to hit the vital organs. I think the 'slope doper' rates quite highly in the rankings of 'useless kit' that you can carry, probably somewhere in between a 'Butt-Out' tool and a 'Cough Muffler'! Which reminds me..... I must sort out the patent on my latest design of fart suppressor.
MS

There was I thinking deer were flat! LOL
You are right MS, the slope doper is OTT for inclusion in the field kit. - - I wouldn't buy one for sure! -- The main value of the images I'v seen of it, is that it is a good graphical indicator of the necessary compensations to be made should one decide to shoot at an angle at longer ranges. It answers the question "How much should the compensation be?" in a very understandable way.

Ian

 

[Solwaystalker]

He's from the North. They have hills up there. He must know what he's talking about
Im from further North and i dont have a clue

 

[Woodsmoke]

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

 

[Alantoo]

No.. even a fast traveling rifle bullet will hit the dirt very quickly if fired parallel to the ground.. Myth Busters did this.. fired a hand gun parallel to find where the bullet hit the ground an then dropped a bullet from the same height at that distance whilst firing the gun again... both bullets hit the ground simultaneously.

It depends…certainly not "No"…

Was the gun fired parallel to a flat or level surface?




If the ground is level then is the barrel levelled at the point of firing?

1) If the bullet travels a mile from a barrel levelled at the point of firing, the bore will be pointing 8" higher above the ground at the landing point.

2) If you bore-sight it at a target which is set at the same (shoulder) height above the earths surface a mile away it will obviously hit the ground in less time than the 1) ….but the two heights were level?

If the surface is flat then it will only be level at one point where it is tangential to the earths surface…and there will be less height for the fired bullet to fall...

Which of the above scenario gives the same length of time as the straight fall from shoulder height?

Of course this would all be so much simpler if they hadn't insisted that we no longer have a flat earth.

Alan

 

[Monkey Spanker]

Right, I tried to keep it simple, but the following post might be confusing the issue:

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

Whilst this is effectively true, it gives the misconception that there is a reduction in range which there isn't! It could also be said that the vertical distance to the target has even increased!
The distance to the targets is still the same. The bullet travels the same distance and remains in the air for the same amount of time. It is the angle of the flight path with respect to the gravitational pull of the earth that alters the elevation from zero.
MS

 

[Alantoo]

Right, I tried to keep it simple, but the following post might be confusing the issue:



Whilst this is effectively true, it gives the misconception that there is a reduction in range which there isn't! It could also be said that the vertical distance to the target has even increased!
The distance to the targets is still the same. The bullet travels the same distance and remains in the air for the same amount of time. It is the angle of the flight path with respect to the gravitational pull of the earth that alters the elevation from zero.
MS

Posts No.5, 6, 11 and 12 said much the same...

The aiming low when elevated or declined is largely irrelevant around the 100yard stalking range, the allowance for the centre of the 3 dimensional chest cavity has much more relevance as you stated earlier. But the OP made no mention of his target.

The only time I have used compensation is when shooting squirrels up a tree with a 12ft lb air rifle. I wondered why I kept shooting over their heads.

Alan

 

[daw]

Thanks for the replies.

So you need to ascertain the horizontal distance (bottom line of triangle) to the target and use that distance not the actual distance (long side of triangle).

This is because gravity only works on the horizontal distance the bullet travels?

 

[Alantoo]

Thanks for the replies.

So you need to ascertain the horizontal distance (bottom line of triangle) to the target and use that distance not the actual distance (long side of triangle).

This is because gravity only works on the horizontal distance the bullet travels?

Yes. That is how the angle compensation works in the laser rangefinders.

Alan

 

[Vipa]

A nice simple explanation...

Gravity is no longer operating at 90° to the bullet, so gravity does less (a fishing rod at 45° sags less than a horizontal one, OK?).

The method above does have some issues which are down to the height of the scope above the bore but otherwise works perfectly well.

 

[JabaliHunter]

Right, I tried to keep it simple, but the following post might be confusing the issue:



Whilst this is effectively true, it gives the misconception that there is a reduction in range which there isn't! It could also be said that the vertical distance to the target has even increased!
The distance to the targets is still the same. The bullet travels the same distance and remains in the air for the same amount of time. It is the angle of the flight path with respect to the gravitational pull of the earth that alters the elevation from zero.
MS

You know that, I know that, but the OP asked for a simple explanation. As you say, it is effectively true...

 

[Mossypaw]

An interesting point on vertical shooting. The nephew of a keeper I used to work under years ago was a sniper in the forces, think it was the Marines. I remember him telling us about going to the Grand Canyon as part of his training to learn vertical shooting. I don't think I understood it then, and still don't, but a bullet fired vertically does not travel in a straight line, it is pulled by the rotational force or something, so they had to allow for it just as you would compensate for gravity.

 

[Vipa]

An interesting point on vertical shooting. The nephew of a keeper I used to work under years ago was a sniper in the forces, think it was the Marines. I remember him telling us about going to the Grand Canyon as part of his training to learn vertical shooting. I don't think I understood it then, and still don't, but a bullet fired vertically does not travel in a straight line, it is pulled by the rotational force or something, so they had to allow for it just as you would compensate for gravity.

Coriolis effect... the spin of the earth... most decent ballistic computers will account for it

 

[Alantoo]

Coriolis effect... the spin of the earth... most decent ballistic computers will account for it

I can still remember my geography teacher getting us to repeat Ferrel's Law, "Owing to the rotation of the Earth the winds in the Northern Hemisphere are deflected to the right….50 years in a flash...

Alan

 

[AN DU RU FOX]

Went looking for the coriolis as a teenager,didnt know wether it was uphill or downdale then either,hhmmm was it a coriolis? nah misses says its a clitoris! Dont google it,

 

[Vipa]

Went looking for the coriolis as a teenager,didnt know wether it was uphill or downdale then either,hhmmm was it a coriolis? nah misses says its a clitoris! Dont google it,

Don't think my ballistics computer accounts for the clitoris effect!!!