Due to some of the very helpful links and suggestions I got from the last time I posed this question,I purchased the Sierra Infinity 5 program,as their angled shot calculation formula is supposedly more accurate that the simple cosine of angle calculation.I had minor trouble running thru the routines but it is coming together
I just wanted to share some results
I am using a 300RUM at 3320 fps 168gr bullet
Because I expect long shots to be mandatory I thought I would zero in the rifle a little higher,lets say for 300y.That would give a max bullet path of +3.5" at around 150-200y.
Versus -8" at 400y,level shot

Now, for an angled shot at 45 degrees:
I would then get a max bullet excursion of 5.5"
at around 225y, at 300y I would still shoot ~ 5" high (4.7") and my zero would be at around 400y,at 500y my drop would be 7" (rounded)

As every can see the deviations are significant enough to miss the target,allowing for shakes,wind,,rock&roll , if one does not take the altered bullet drop.
In particular I would maybe shoot too high in a short distance shot at 200-250y !

All that makes me think I should have a little inclinometer to guestimate angle of shot better.
I think I have trouble calling a 30 deg from a 45 deg etc

Does anyone have an idea of maybe a home built contraption that helps guestimating the angle?

sheephunter

I have a a MilDot Master (it offers a method to get angle), a Slope Doper and gave away my Angle
Good to hear you've found something worth while... I'm still playing with Excel spreadsheets trying to come to grips with the problems and solution(s). (It's what I enjoy!)

Cosine Indicator.

Slope Doper and MilDot Master
http://www.ustacticalsupply.com/mildot-slope.shtml

Angle Cosine Indicator
http://www.snipertools.com/aci.htm

Buy or make one, these should give you enough examples.

[ 08-07-2003, 19:33: Message edited by: David King ]

Thanks David,

it shows ,"you have been there"
I reviewed your links,the offered products look helpful to me.
Sounds like one should be able to measure angle with a simple little protractor and a string to get vertical.Thats the method the Mil-Dot seems to use or better said the Slope doper?

The Angle Cosine indicator,from the ad, seems more accurate, as doping the angle by looking down a protractor while keeping it aligned with vertical doesnt sound that accurate to me,meaning
accurate to ?~ 10 degrees,handheld?

It sounds in your hands though ,you came to a different conclusion as you dont use the angle indicator.I value your experience.Would you mind telling us the details,and how you can measure angle with the slope doper =~ protractor to ?5-10 degrees accuracy.

At this time I dont have a Mildot reticle,(I know that shows my diaper age),using a laser to get distance,so angle is what I need.

thanks so much for your constructive help

sheephunter

Sheephunter

I'd say that for the bunch I stated you'd be okay with the Angle Cosine Indicator. I gave mine away as a fella didn't have one and wanted it for a comparison study/article. You cold probably make one that attaches to the rifle/rifle scope and is simple and accurate. incline the rifle while viewing through the scope and then "trap" the weighted string and read the angle. The greater the distance from the central axis to the edge of the device the more accurate the reading...look at the Slope Doper..buy a plastic protractor...some braided string... a small weight...duct tape... and you have a rapid prototype.

Good luck and let us know how things work out.

/r

The conditions under which I shoot angles are not the same you experience or are about to experience. I shoot "angles" in competitions, these angles and/or related distances are inconsequential when one considers the target size(s) and trajectory of the rifles involved (up to about 45 to 50 degrees but the distance is under 100 yards and the targets are generally 4 to 6 inches across).

I have tried what I consider extreme long range shooting once (just a few yards short of a mile, treeline limited) using a series of calculation I had developed/liberated. It became apparent to me that "angles" at those distance takes on a completely new meaning...we go from 30 degrees and minimal effect at shorter ranges to 5 degrees and significant effect at a mile. This prompted my first dive into the "what the hell is going on with angled fire" pool. I haven't had the opportunity to try a controlled set of shoots to develope and test the equations and equipment required for precision shooting at extreme ranges for "angles". Hopefully with this latest tidbit from Gustavo and offerings from others (Tiro Firo (sp?)) and Sierra I can come to grips with a more complete understanding of the actual effects vs the "commonly accepted near truth" about these matters. There are procedures accepted as common practice that would negate the need for an in depth understanding of inclined fire effects but the methods I use for hunting require first round hits and eliminate the use of those procedures. I have a desire to know what is happening or about to happen and have a little difficulty with accepting something that is a know gross approximation...

When I get back into this problem I'll probably use several methods to check the angle, inclinometer, GPS and maps.

There are also laser rangefinders that show angle and compass heading to the target (Leica Vector I believe for one).

That slope-doper is a good idea! I could use one an may just have to try it out. Thanks.