Shooting at angles / angle cosine

[LaHunter]

Can someone that knows explain to me how angle cosine works for shooting angles. What is the math involved. I know there are range finders out there that do the math for you, but I can't spend that kind of money. I have a Leica 1600 that will tell me the sight angle.

EXAMPLE: I am shooting a 'raw' distance of 430 yards at an angle of 35 degrees.
The cosine of 35 degrees is .819 (I have a calculator that knows this).
Do I multiply 430 yards by .819 to get a 'shoot to' distance of 352 yards?


Thanks for educating me on this. I am heading to Big Horns in WY in late October and hopefully I may get to use this info.

 

[CB11WYO]

... EXAMPLE: I am shooting a 'raw' distance of 430 yards at an angle of 35 degrees.
The cosine of 35 degrees is .819 (I have a calculator that knows this).
Do I multiply 430 yards by .819 to get a 'shoot to' distance of 352 yards?...

Yup that's right.

I also believe a slightly more accurate way to calculate the same thing is to take your .819 cosine and multiply it by your BULLET DROP instead of your YARDAGE. But there has to be some pretty long distances and/or some pretty steep angles to notice a large difference between the two methods.

I've found some good stuff on this topic using the "Search" on this site.

 

[junkpile]

[ame]http://m.youtube.com/watch?v=cKqZdHRlKfo&feature=plpp[/ame]

this guy does a pretty good job on his sniper 101 series. Kind of redundant and rambles some, but stays on topic pretty well. He has a pretty nonconventional approach to shooting in a lot of respects. I think he has 2 videos on angle of fire corrections.

He discusses using a cheap plastic protractor and determining your own corrections rather than having a rangefinder calculate it for you. If you remember your trig from high school, it's relatively simple.