Warren-- This should fill in some of the blanks, I hope this helps.
5 degrees = .0038
15 degrees = .0341
25 degrees = .0937
35 degrees = .1809
85 degrees = .9128
90 degrees = 1.0
As you may see, the changes are small but become more and more critical as range increases. I admire your determination to get it right the first time. You will get a lot of advice from people about how to do things. What most of these advice givers do not understand is the relationship of multiple errors and how several small errors will add up to a big MISS! You may have read a recent post about mil radian spacing, and one advice giver wrote that using an 'estimate' would suffice. Try to imagine a simple shot from 1200 yards with a 30 degree incline and a 4.7 percent ranging error, now....compound that error with the error from using a ACI and the wrong inclination formula. Both errors could sum and cause you to shoot low. Which will result in you shooting so FAR UNDER the target you will be left scratching your head. This is why guys wind up taking "spotter shots". Their methods have these little flaws in them, and they can not understand the interaction of all of the small errors. OOPS....MISSED AGAIN! [img]images/icons/shocked.gif[/img] Not all errors sum, they can cancel eachother out occasionally, and you could get lucky.....does everybody FEEEEEEEEEL LUCKY? I think in the real world, every one feels Mr. Murphy's presence. What Teo said about the wind is true, but you can learn to deal with it. One shot kills at 1,000 yards are common with todays technology, even in mountainous terrain. We hunted in Utah last year, and had a shooting contest in between Elk and Mule deer season. One shot at an Elk sized torso at 500 yards, if you hit, you are still in, if you miss, you are out. Out of 12 guys in the contest, 3 made it to 900 yards with hits at that distance. 1 of the guys had no formal training, just a car salesman from Salt Lake. The two with training and experience went to 1400 yards, and the winner went to 1500, and could have gone further, just ran out of time.
P.S. The error correction factor for any angle is 1.0 - the angle's cosine.
Keep shooting with precision, and keep thinking with precision, you will shoot farther and straighter than most. I think CrowMag says it best.....
"If you think something is not possible move out of the way so the ones that are doing it can "
Antslayer, as you said, ocassionally Murphy`s law does get us all, but knowing how to do something and not knowing makes all the difference in the world. The more we can learn about what we`re doing, the more we can do with it and I just love that.
As already stated, I`m a newby to this longrange game in mountainous terrain and I very much appreciate all of the replies. I can now get started with more confidence.
Hi Warren. This may be a bit late for your trip but others may find this useful. The data below can be used to find the horizontal distance to the target from the incline angle and slope (measured) distance.
0 deg (horiz.), multiply slope distance by 1
5 deg, multiply slope distance by 1
10 deg, multiply slope distance by 0.98
15 deg, multiply slope distance by 0.97
20 deg, multiply slope distance by 0.94
25 deg, multiply slope distance by 0.91
30 deg, multiply slope distance by 0.87
35 deg, multiply slope distance by 0.82
40 deg, multiply slope distance by 0.77
45 deg, multiply slope distance by 0.71
50 deg, multiply slope distance by 0.64
55 deg, multiply slope distance by 0.57
60 deg, multiply slope distance by 0.5
A useful instrument for measuring angles is a clinometer. Some of the Silva compasses have these built in, while Brunton makes one called the CM Clinomaster and Suunto also makes a good one called the PM-5/360 PC. The used Suunto ones sell on e-bay for about $50.
Hope this helps. I was wondering when that engineering degree would come in handy.