How does shooting angle effect ballistics?

[goodgorilla]

I'm guessing when your shooting upwards the bullet is going to drop more from crosshairs, and the opposite shooting downwards. I know you can plug the angle into a ballistic calculator, but is there another way to do it with a scope with some equations?

 

[Sterling Shooter]

Whether shooting uphill or downhill, the straight line distance to target will be greater than the flat ground distance to target. Since the effects of gravity are felt by the flat ground distance to target the sight must be adjusted to the flat ground distance to prevent shooting over the target. To make necessary sight adjustment use a clinometer to determine angle and then take the cosine for that angle as found on a cosine table and multiply the cosine by the straight line distance to target. This will get you the flat ground distance to target. Beginning with Angle = Cosine:

Cos (a) X Straight Line Distance = Flat Ground Distance

See YouTube video: USAMU Angle Shooting Pro Tips with Praslick

 

[djskit]

Yep, its not the actual distance to the target, but the horizontal distance that counts.

You will see some of the range finders have this feature built in.

As I say to my friend that can never figure this out:

If you point your rifle straight up (90 deg) how much will the bullet drop? Answer: Zero
If you point your fifle straight down (90 deg) how much will the bullet drop? Answer: Zero

 

[goodgorilla]

Whether shooting uphill or downhill, the straight line distance to target will be greater than the flat ground distance to target. Since the effects of gravity are felt by the flat ground distance to target the sight must be adjusted to the flat ground distance to prevent shooting over the target. To make necessary sight adjustment use a clinometer to determine angle and then take the cosine for that angle as found on a cosine table and multiply the cosine by the straight line distance to target. This will get you the flat ground distance to target. Beginning with Angle = Cosine:

Cos (a) X Straight Line Distance = Flat Ground Distance

See YouTube video: USAMU Angle Shooting Pro Tips with Praslick

What great channel thank you.

Others have explained it well, but get a calculator, angle to cosine chart, mildot master, cosine indicator etc..... To go with you Ranging device if it doesn't convert it to Gravity Distance for you.

Cosine x distance to the target = GD

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I have a mildot master and a leica 1600b which has the angle thing on there. Why not use the angle indicator mounted to the scope? What is a cosine indicator? After reading the manual to it, it seems that I need to learn some other stuff first before learning that. This weekend I will be chronographing some .22lr's. With the average speed, I'm going to see what I can do with that information.

one stupid question, would a 20moa scope mount effect a indicator like this one?
http://www.midwayusa.com/product/22...atinny-style-mount-matte?cm_vc=ProductFinding

That device looks a little bulky, perhaps I should use one of those hand held indicators. Either way, does a 20moa rail effect anything?

 

[goodgorilla]

No you find your barrels level, then level the device (cosine or angle indicator).

If you know the angle you still need the cosine.. If I had to choose between the two it would be the cosine indicator)

Badger Ordnance Angle Cosine Indicator Kit Generation 2

Or the scope mount with level..

But this all can be done with rough angle estimates

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That cosine indicator is nice. I don't know what I was thinking about the scope mounted indicators. I think I just imagined it up spontaneously.

 

[djskit]

I prefer the angle indicator version as that is what my ballistic program accepts - does the cosine part for me.

 

[Sterling Shooter]

There's a clinometer AP you can download to you smart phone. I like it as it gives a verbal for angle and can hold the angle too. I also use my compass which has a clinometer but it is awkward.

 

[djskit]

Ballistic AE has an angle clinometer built in - but you have to look down you Iphone and line up the target and hit a lock button. Easier to read the angle off the rifle and hard type it in.

 

[Jaeger308]

Remember however that you still need to use the slope distance or total distance for wind calls and time of flight mover calculations. The straight up or straight down drills, you still need to dial out the line of bore to line of sight distance for proper point of aim point of impact.

 

[goodgorilla]

Remember however that you still need to use the slope distance or total distance for wind calls and time of flight mover calculations. The straight up or straight down drills, you still need to dial out the line of bore to line of sight distance for proper point of aim point of impact.

I have not begun to calculate wind or moving targets. However, which distance do you use when doing wind or mover? The strait line distance, or the total ground distance? I'm guessing the strait line distance.

 

[goodgorilla]

I think you are confusing (at least to me) the three distances that are commonly referenced to a high angle target.

1- GD or Gravity Distance - is the adjusted (from the angle or cosine read) distance to your target.
2- Distance to target (or the straight line distance) - is exactly that, and used for wind, time in flight and movers.
3. Ground distance - is the distance you would take if you had to move to your target. In an ELR scenario you might have several valleys to navigate. Some ground mapping software will report in total ground distance. This has no impact on the external ballistics.

Jt

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Sterlingshooter gave me this equation:
Cos (a) X Straight Line Distance = Flat Ground Distance

It should be
Cos (a) x Strait Line Distance = Gravity Distance?

 

[Jaeger308]

Sterlingshooter gave me this equation:
Cos (a) X Straight Line Distance = Flat Ground Distance

It should be
Cos (a) x Strait Line Distance = Gravity Distance?

Yes

 

[M40_A1]

Sterlingshooter gave me this equation:
Cos (a) X Straight Line Distance = Flat Ground Distance

It should be
Cos (a) x Strait Line Distance = Gravity Distance?

Flat ground distance IS gravity distance. Flat ground distance is not the same as the ground distance that Diver mentioned.