Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels and Ballistics


Reply

Angle Doping

 
LinkBack Thread Tools Display Modes
  #1  
Old 03-07-2007, 10:59 PM
TMR TMR is offline
SPONSOR
 
Join Date: Mar 2006
Location: Elma, WA
Posts: 497
Angle Doping

Can someone explain why when I take the cosine of an angle and multiply it by the LRF distance, it does not match up with exbal? If I use the same angle, I get two different numbers for scope dialing. I am trying to decide if I need an ACI or if an angle finder and the pda will do it.

Example:
35* angle(.819 cosine)
867 yds
MOA needed = 9.75

Exbal
35* Angle
867 Yards
MOA needed = 10.5

Not a huge difference, approx. 6" at that range. Maybe I should just enter the angle in exbal on the pda and go that route. Any advice???
__________________
Travis Redell
R Bros Rifles
www.rbrosrifles.com
Reply With Quote
  #2  
Old 03-08-2007, 09:09 AM
Platinum Member
 
Join Date: Jun 2001
Location: Potomac River
Posts: 5,057
Re: Angle Doping

I expect Xbal does the calculation a little differently than you do it.

Multiply the cosine times the <u>drop</u> for the actual distance you measured. This will get you closer to the correct answer but still no cigar.

What the cosine of the angle does is make corrections for the angle of the bullet flight with respect to gravity. Because the bullet path is a curve, the angle is constantly changing and is very complicated to compute precisely. Correcting the drop- not the distance -will get you closer to the actual answer.
__________________
The Smokin Fur Rifle Club
Reply With Quote
  #3  
Old 03-08-2007, 10:45 AM
Platinum Member
 
Join Date: Jan 2004
Location: Blackfoot, Idaho
Posts: 8,101
Re: Angle Doping

Darn, I wouldn't have thought that the difference would be that much [img]/ubbthreads/images/graemlins/confused.gif[/img]

Guess I'd better get xbal for the pocket PC. [img]/ubbthreads/images/graemlins/frown.gif[/img]

The records (posts) show that of the two methods you use, xbal is the one to trust.
__________________
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
Reply With Quote
  #4  
Old 03-08-2007, 11:17 AM
Platinum Member
 
Join Date: Jan 2003
Location: The rifle range, or archery range or behind the computer in Alaska
Posts: 3,515
Re: Angle Doping

Multiplying the cosine with the yardage only gets you close. Using exbal will be dead accurate. There is more to it than simply multiplying the two numbers for exact results.
__________________
Long range shooting is a process that ends with a result. Once you start to focus on the result (where the shot goes, how big the group is, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
Reply With Quote
  #5  
Old 03-08-2007, 04:32 PM
Platinum Member
 
Join Date: Jun 2001
Location: Potomac River
Posts: 5,057
Re: Angle Doping

TMR

Here are the instructions for the Cosine Angle Indicator.

Of importance to your question are the last three paragraphs.

You used Method #1 and Method #3. I recommended you use Method #2 as being better than #1 but not as good as #3.

Would you like me to say that one more time real slow. [img]/ubbthreads/images/graemlins/grin.gif[/img]



Drops
__________________
The Smokin Fur Rifle Club
Reply With Quote
  #6  
Old 03-08-2007, 08:01 PM
TMR TMR is offline
SPONSOR
 
Join Date: Mar 2006
Location: Elma, WA
Posts: 497
Re: Angle Doping

BB,

got it......I will use my PDA and Exbal....unless the battery dies. Then I will get the calculator out.
__________________
Travis Redell
R Bros Rifles
www.rbrosrifles.com
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: Angle Doping
Thread Thread Starter Forum Replies Last Post
Doping the Wind Broken Brow Turkey Hunting 0 05-30-2011 12:19 PM
another wind doping question dbleyepatches Long Range Hunting & Shooting 8 02-03-2010 07:50 PM
angle cosine or angle degree trueblue Long Range Scopes and Other Optics 11 06-26-2008 09:42 PM
Hey experts, Can we have a lesson on wind doping? arthurj The Basics, Starting Out 29 11-27-2007 08:52 PM
Angle Doping??? IChaseCoues The Basics, Starting Out 30 12-03-2006 06:38 PM

Current Poll
Do you archery hunt for elk?
YES - 34.32%
116 Votes
NO - 48.52%
164 Votes
Not yet, but I plan to. - 17.16%
58 Votes
Total Votes: 338
You may not vote on this poll.

All times are GMT -5. The time now is 01:18 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC