shooting uphill or downhill

[wpjson]

My point was, it takes increased energy to lift the ball against the force of gravity. All things being equal it takes more energy to rise than to go flat or drop. The energy used for lift is taken from the force drving the ball forward.

 

[George]

My point was, it takes increased energy to lift the ball against the force of gravity. All things being equal it takes more energy to rise than to go flat or drop. The energy used for lift is taken from the force drving the ball forward.

Yes, I understand that and agreee. Your physics teacher had it right, both as to the mechanism and the degree. That's an entirely different thing than the type of error I'm talking about, though. Two different mechanisms, two different errors.

There are a lot of things which effect the path of a bullet”¦air temperature, humidity, altitude, etc., etc. Some are so small as to be completely negligible, such as that described by your teacher, but some are great enough that they need to be factored in under certain circumstances, such as the incline angle.

It's a fact that guns shoot higher on humid days than on dry days, on hot days than on cold days, but neither are things we need to worry about. They also shoot higher in a tail wind than in a head wind, not usually enough to be a problem, either.

Spence

 

[BrownBear]

Drop the hammer. Balls and gravity can't read.

 

[wpjson]

Yep.

 

[George]

I enjoy discussing black powder ballistics. I like to know how things work. I know full well after a lot of years on these boards that not many people do, which has always puzzled me, but there it is.

So far as I understand the rules of the forum, participation in such discussions is not mandatory, which should be a great relief to most members. Opting out is a viable choice.

Spence

 

[robinsroost]

A long time ago, in a galaxy far, far away, I read or saw a demonstration that a bullet fired from an absolute level barrel and a bullet of equal weight and size, dropped from the same height would strike the ground at the same time, regardless of the velocity of the fired one. Y'all are still making my head hurt.......Robin :stir: :surrender:

 

[George]

That's true, and it's the basis for most of what we call trajectory. Gravity is a constant, and that means it can never act in a different way on any two objects, regardless of the object's condition or state.

Spence

 

[hanshi]

I'm right brained and don't like formulas and such. When I shoot at a deer and regardless of angle/no angle/etc, I do it as if he has a soccer ball in his chest; that's what I aim at, the imaginary soccer ball. I also never shoot at anything that requires a "hold over". If he's a certain distance away I may aim high on his boiler room but that's it; never "over".

 

[don hepler]

After many years of hunting experience, I came to the conclusion that when you shoot uphill the tendency is to shoot low, and when you shoot downhill the tendency is to shoot high. I think there is a logical explanation. When we shoot at targets they are flat, but a deer is more rounded. Think of the deer as a "globe". On a downhill shot, you are trying to shoot below the equator, but you see mostly the north pole, so you shoot high. On an uphill shot, you are still trying to shoot just above the equator, but you see mostly the south pole, so you shoot low. I bow hunt and it is difficult to shoot at a 3-D target, from an elevated stand, and keep the shot in the kill zone.

I am talking about my actual hunting experiences, and there is definitely more to it than ballistic, and math equations.

 

[Skychief]

So far as I understand the rules of the forum, participation in such discussions is not mandatory, which should be a great relief to most members. Opting out is a viable choice.

Spence

:haha:

 

[cynthialee]

I was taught to NEVER shoot uphill. Some fool could be on the other side of the rise and walk into the field of fire.

 

[wpjson]

not a problem at may cabin. Granite cliff is the backdrop

 

[George]

The kind of error I'm talking about in this thread has nothing to do with the shooter. It's not some optical illusion we have because of the lighting conditions or the shape of the target, it's not the lack of experience shooting offhand, or any of the million things shooters can figure out to prevent hitting the target. It's a built-in error, you cannot avoid it. If you aim directly at the spot you want to hit while shooting steeply uphill or downhill, the bullet will strike high, above that spot. It's like the good-luck horseshoe hanging over the desk of Niels Bohr, one of the world's greatest scientists. A visitor remarked, "You don't believe in that nonsense, do you?". He replied, "No, but they say it works whether you believe it or not."

As I said, the error is worse with steep grades, slow bullets and long distance.

Another name for it is 'slant range error'.

I know it's something only a ballistics nerd can love, but I believe the more we understand about how our guns work the better chance we have of becoming good shooters.

Because this error will rarely if ever effect our shooting, it will be of little interest to the majority of members. But, figuring out why the error occurs can teach us something, and that can be fun for some of us. And it works, whether we understand it or not. :grin:

Spence

 

[longcruise]

Well said :thumbsup:

 

[coloradoclyde]

Angles.....shooting is all about angles... :grin:

 

[azmntman]

I have archery elk then Blk Pwdr deer. This AM I shot about 3o degree down hill at 40 yds and used the 30 yd pin and was right there. Will now have to shoot a few PRB and see what the difference is at say 50 yds. The arrow woulda been a clean miss over if I used 40 yd pin. Gotta figure this out, the herd I have chosen to hunt stays on a hill and I will likely be shooting up or down!