bullet trajectory

[D.F.M.]

Looking for opinions on bullet placement.Example if you have a 300 yd. shot uphill or down hill do you aim for the target at that (straight line) distance or do you adjust for the uphill or down hill shot.

[Huntn coues]

Depending how steep hold low on both.

 

Or get one of those fancy range finders that spits out what yardage to shoot at up hill or down hill.

[SunDevil]

trajectory is not based on line of sight distance but rather horizontal distance effected by gravity. a 300 yard shot uphill or downhill at say a mt goat or sheep would not drop as much as a 300 yard flat shot at say an antelope. the same is true for arrows.

[Red Rabbit]

Shoooting at an angle from Sierra Bullets

http://www.exteriorballistics.com/ebexplained/5th/33.cfm

 

From LR Hunting- easy is the "Improved Rifleman Method"

http://www.longrangehunting.com/articles/angle-shooting.php

[shortpants]

Most of the ballistics I've looked at have taught me that people make a bigger deal out of it than it really is.

 

General rule of thumb is that it doesn't make a big enough difference to worry about it until you get out to 400yds. and/or beyond 30 degrees of angle. Nobody I know is shooting angles like that at 400+yds. Most people over compensate for angles from what I've read and heard.

 

I'm only referring to bullets and not arrows. Arrow flight is affected more by angles.

 

I'm no expert and if I'm wrong I would love to hear if any of you have different experiences.

[SunDevil]

I have only heard of it being a major concern with high elevation and steep terrain hunting. that is why I mentioned mt goats and sheep. on a 300+ yard steep angle shot on a mt goat, the hunter may be tempted to hold over the target (give up hair) and good guides will be aware of this and educate/instruct their client appropriately.

[Red Rabbit]

From reading those two articles on the improved rifleman method, you can see that the bullet drop is a function of the cosine of the angle. (* = degree)

For a 10* slope, the bullet drops 98% of its flat (no slope) vertical drop value.

For a 20* slope, the bullet drops 94% of its flat (no slope) vertical drop value.

For a 30* slope, the bullet drops 87% of its flat (no slope) vertical drop value.

For a 45* slope, the bullet drops 71% of its flat (no slope) vertical drop value.

 

If you are shooting a rifle that drops 20 inches at 400 yards, the actual drop would be close to

19.7" for a 10* slope and 400 yards angled distance.

18.8" for a 20* slope

17.5" for a 30* slope

14.1" for a 45* slope

So with less drop, you would need to hold lower than normal on flat ground.

 

So what shortpants said is fairly true that it matters with angles near and over 30*, and for longer distances.

 

 

[scoutm]

From reading those two articles on the improved rifleman method, you can see that the bullet drop is a function of the cosine of the angle. (* = degree)

For a 10* slope, the bullet drops 98% of its flat (no slope) vertical drop value.

For a 20* slope, the bullet drops 94% of its flat (no slope) vertical drop value.

For a 30* slope, the bullet drops 87% of its flat (no slope) vertical drop value.

For a 45* slope, the bullet drops 71% of its flat (no slope) vertical drop value.

 

If you are shooting a rifle that drops 20 inches at 400 yards, the actual drop would be close to

19.7" for a 10* slope and 400 yards angled distance.

18.8" for a 20* slope

17.5" for a 30* slope

14.1" for a 45* slope

So with less drop, you would need to hold lower than normal on flat ground.

 

So what shortpants said is fairly true that it matters with angles near and over 30*, and for longer distances.

 

 

Ok professor, these kinds of posts are just begging for that "Ask Doug" forum we discussed. And what's a cosine? I remember hearing something about that in junior high but don't really recall what it is.

[Red Rabbit]

The cosine of an angle is the length of the adjacent side divided by the length of the hypotenuse of a right triangle.

cos A = adj/hyp

Multiplying the lasered distance at and angle (hypotenuse) by the cosine of the angle gives the horizontal distance (adjacent side). adj = (hyp)(cos A)

[scoutm]

The cosine of an angle is the length of the adjacent side divided by the length of the hypotenuse of a right triangle.

cos A = adj/hyp

Multiplying the lasered distance at and angle (hypotenuse) by the cosine of the angle gives the horizontal distance (adjacent side). adj = (hyp)(cos A)

 

 

huh????

[Red Rabbit]

http://www.algebralab.org/lessons/lesson.a...igSinCosTan.xml

http://mathworld.wolfram.com/Cosine.html

[Huntn coues]

http://www.algebralab.org/lessons/lesson.a...igSinCosTan.xml

http://mathworld.wolfram.com/Cosine.html

 

 

 

So in other words hold low

[scoutm]

http://www.algebralab.org/lessons/lesson.a...igSinCosTan.xml

http://mathworld.wolfram.com/Cosine.html

 

 

 

I'm too old to have to re-learn something I forgot 20 years ago. Thanks for trying to educate a simpleton like me though.