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# Shooting up hill/ Shooting down hill?

#22
04-16-2011, 09:43 PM
 Silver Member Join Date: Feb 2011 Location: AZ Posts: 191
Re: Shooting up hill/ Shooting down hill?

Quote:
 Originally Posted by WildRose Your formula gives only the range, it ignores the diffent effect of gravity on bullett drop when shooting extreme angles.
okay now i am confused! i thought gravity was a constant and was negligible due to angle? horizontal distance, drift, rotation, what am i missing about effect of gravity for shooting?
#23
04-17-2011, 12:22 AM
 Official LRH Sponsor Join Date: Feb 2011 Location: N. Texas and S. Africa Posts: 8,097
Re: Shooting up hill/ Shooting down hill?

Quote:
 Originally Posted by rcdinaz okay now i am confused! i thought gravity was a constant and was negligible due to angle? horizontal distance, drift, rotation, what am i missing about effect of gravity for shooting?
You would be in error.

When shooting up or down at a high angle the drop of the bullet for each yard travled is going to be a great deal less than a bullet fired at a target at your same elevation.

Think of it this way, if you are shooting either stright up or straight down, the only real effect gravity has on the bullet is on it's velocity.

When fired paralell to the earth, the bullet falls at a predictable rate based on the pull of gravity. For each yard of forward travel, you have a specific rate of drop.
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#24
04-17-2011, 04:33 AM
 Bronze Member Join Date: Jan 2011 Posts: 62
Re: Shooting up hill/ Shooting down hill?

I am also wanting to have a better understanding of shooting at angles. I used to think that when you were shooting uphill you would have to aim high, due to gravity pulling you back down. And having to aim low when shooting downhill because you are going with gravity.

Now I know that's wrong because I've read everywhere that it doesn't work that way. But could someone help me paint a picture in my mind of why exactly it doesn't work that way.

Scott
#25
04-17-2011, 08:43 AM
 Silver Member Join Date: Jan 2010 Location: utah Posts: 366
Re: Shooting up hill/ Shooting down hill?

Quote:
 Originally Posted by Scott300RUM I am also wanting to have a better understanding of shooting at angles. I used to think that when you were shooting uphill you would have to aim high, due to gravity pulling you back down. And having to aim low when shooting downhill because you are going with gravity. Now I know that's wrong because I've read everywhere that it doesn't work that way. But could someone help me paint a picture in my mind of why exactly it doesn't work that way. Thanks for your help, Scott
heres a quick and easy way to visually explain whats happening. take a tape measure extend it out horizantally and make note were it breaks over. now take that same tape and pull it out on an angle both up hill and down hill. then note how far HORIZANTALLY it is when it breaks. you'll get more tape out but it will break in reletively the same horizantal distance

heres the actual math for the riflemans rule

most simplify it to cosine x distance others use thier drop tables for the distance to target and use cosine x drop the result is fairly close to each other less than 1 minute of angle.
#26
04-17-2011, 08:49 AM
 Silver Member Join Date: Jan 2010 Location: utah Posts: 366
Re: Shooting up hill/ Shooting down hill?

Quote:
 Originally Posted by rcdinaz okay now i am confused! i thought gravity was a constant and was negligible due to angle? horizontal distance, drift, rotation, what am i missing about effect of gravity for shooting?
it is a constant and the bullet does encounter the same gravity. however the linear moment "spine" of energy is working differently against/with gravity than when shot horizantal. eventually you get to a point were none of this math will work the same for up/down hillbut then your shooting cannons!
#27
04-17-2011, 10:31 AM
 Silver Member Join Date: Feb 2011 Location: AZ Posts: 191
Re: Shooting up hill/ Shooting down hill?

Load thanks for the cannonball example, I found some similar analogies to satellite flight/launch and a golf ball example. I think I am on the same page and looking at the Sierra link (below) we can still pretty much assume gravity is a negligible based on it being constant (9.8m/s). I think I was confused more by semantics... time of flight vs gravity. As you mentioned there is some difference in the theoretical realm especially at extreme angles of 90 deg & 180 deg but am I correct that for trajectory calculations most will use it is not really a factor?

Sorry to beat a dead horse on this still trying to make sure I have a proper grasp on this topic. I am rally looking at this trying to determine at what ranges a rifle mounted angle indicator starts to reach its limit on usefulness and if there are any possible errors/assumptions to be aware of in most of the ballistics programs out there.

It has been over 20 years since I had to actually do the math and the trig and calc equation make my head hurt.

exterior ballistics
#28
04-17-2011, 10:35 AM
 Gold Member Join Date: Aug 2008 Location: east central fl. /n.c. pa. Posts: 850
Re: Shooting up hill/ Shooting down hill?

very good and spirited debate. even some spelling lessons thrown in.
BOB, dont feel bad about the misspelled name. it could have been worse. lol

my personal take is that angle shooting is but one of the important things involved.
there are others and all need be considered equally.
a miss is a miss wether caused by angle, wind, bad position, etc.
be aware of these things and find what works for you and your style of hunting.
all of our hunting is done from lookouts. we dont move about as some do in other areas.
all shooting is done from some sort of bench also.
an angle indicator and a cheap calculator or premade chart work well for us.
my engineer grandson simply holds his ipod next to the barrel and has an answer in seconds. usually while im looking for my chart.

sooner or later your just going to have to shoot.
hopefully at least some thought has been given to a miss.

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