Long Range Hunting Online Magazine Angle Shooting - Correcting For The Effects Of Gravity by Ward Brien
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# Angle Shooting - Correcting For The Effects Of Gravity by Ward Brien

#29
06-03-2012, 01:50 PM
 Junior Member Join Date: Apr 2012 Location: Arliington, TX Posts: 16
Re: Angle Shooting - Correcting For The Effects Of Gravity by Ward Brien

Good afternoon all! Let me throw in my 2-cents.

As posted elsewhere within LRH forums about shooting on angles the ACI and related eqpt (TBR, etc) all rely on high school geometry and trigonometry. Whether you calculate a shooting distance by multiplying a sighting distance by a cosine or measure the angle and apply the proportions of a 30-60-90 the numbers come out to be about the same. (Who is going to dispute where to hold when one method says the gravitationally affected shooting range is x50yd and the other calculates x54yd? Who?!)

My problem is this: In that other forum the TBR, as applied by that author, clearly proved out that its electronic programming was using the aforementioned HS trig and geom; using it planted the bullets 6 inches too high. The ACI is a manually calculated application of the same software inside the TBR, thus hitting high will still be the likely result.

Let me show what I'm saying. This article happens to mention a 500yd target 30 degrees uphill >>> 435 effective shooting distance. The other article, Saga of the Uphill/Downhill Shot, mentions a 400yd target 30 degrees downhill >>> 350yd effective shooting distance. Let's calculate for ourselves by an old-school method the distances, and this applies only to the specific 30 degree angle in both articles.

sighting distance/angle 500/30
vertical height above shooter 250
30-60-90 multiplier square root of 3 (~1.73)
divide the sighting distance by 2
then multiply by 1.73 = 432.5 yd
or
multiply the vertical height by 1.73 = 432.5

The other article:
sighting distance/angle 400/30
vertical height below shooter 200
30-60-90 multiplier square root of 3 (~1.73)
divide the sighting distance by 2
then multiply by 1.73 = 231.2 yd
or = 231.2 yd
multiply the vertical height by 1.73

I'm not trying to say I'm right about anything, no not at all. What I'm driving at is this: Though both devices surely speed up the process of getting a more reliably close shooting range dialed into your scope putting the bullet precisely on target will still require plenty of practice.

One other contributor wrote this: D.O.P.E. (Data On Previous Engagements).

Practice my friends with all the tools and aids you can afford and find useable!!

JP
#30
08-03-2012, 04:55 PM
 Bronze Member Join Date: Jul 2010 Posts: 40
Re: Angle Shooting - Correcting For The Effects Of Gravity by Ward Brien

I may be asking a dumb question but I've never found any information on this. I understand how to figure the shooting distances for steep inclines by using the cosine. My question is, does the energy and fps remain the same for the actual shooting distance of say 500yrd or is it the same for the shoots like distance of 250yd using the cosine for a 60 degree slope?

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