Shooting Up Hill

[vladtepes 1,060]

292 yards to target 84ft in elevation between 0 and target 

what do I need to consider, I have made the shot with my 14in AR15 with a high hold on steel plate. I am going to shoot with my 308 AR but on paper so I am looking to see if I can do more than just ring a man sized steel plate.  

thanks 

[JackDaWack 2,895]

I beleive you should expect the impact point to be slightly higher than normal(level).

A bit more on that. http://www.rifleshootermag.com/network-topics/tips-tactics-network/hitting-a-high-or-low-angle-shot/

[RichP 115]

You can get a angle compensating rangefinder to give you the horizontal distance to the target, but as stated above, your shot will be slightly higher as the distance will be closer than 292 yards. 

To be clear, when I say slightly, we're talking about less than an inch at that distance.

[vladtepes 1,060]

so what you mean by this is normal adjustment for range, but slightly less adjustment due to the raise in elevation? 

If anyone is interested this is the exact shot.. 

 

[Zeke 5,504]

Draw your ballistic  parabola then super impose it for angle of inclination.

Kindy visual aid Kentucky windage. 

[RichP 115]

Bullet drop is affected by horizontal distance only. Your making me use a calculator!

 

so, if you have 84 ft of elevation and a measured distance of 876 ft (292 yds.) then your horizontal distance would be 872 ft.

Therefore, you adjust for 290 yards and fire away.

 

BTW - you do the same for downhill shots.

[Zeke 5,504]

3 minutes ago, RichP said:

Bullet drop is affected by horizontal distance only. Your making me use a calculator!

 

so, if you have 84 ft of elevation and a measured distance of 876 ft (292 yds.) then your horizontal distance would be 872 ft.

Therefore, you adjust for 290 yards and fire away.

 

BTW - you do the same for downhill shots.

Gravity.. thanks Newton! Asshole 

[Bully 749]

1 hour ago, RichP said:

Bullet drop is affected by horizontal distance only. Your making me use a calculator!

 

so, if you have 84 ft of elevation and a measured distance of 876 ft (292 yds.) then your horizontal distance would be 872 ft.

Therefore, you adjust for 290 yards and fire away.

 

BTW - you do the same for downhill shots.

Do you know the formula off the top of your head by chance. 

 

I can look it up but maybe post it here for all?

[RichP 115]

pythagorean theorem

there are a ton of calculators for it online. I used this one https://www.miniwebtool.com/pythagorean-theorem-calculator/

 

[Zeke 5,504]

7 minutes ago, RichP said:

pythagorean theorem

there are a ton of calculators for it online. I used this one https://www.miniwebtool.com/pythagorean-theorem-calculator/

 

A^2 +b^2= c^2

but uphill has a negative gravity vector.

downhill has a positive gravity vector.. but this is negligible hard math right nerd @10X?

[10X 3,296]

20 minutes ago, Zeke said:

A^2 +b^2= c^2

but uphill has a negative gravity vector.

downhill has a positive gravity vector.. but this is negligible hard math right nerd @10X?

I’m more the science nerd, but I think RichP has it right, it’s only the horizontal distance that matters...though that can be hard to determine. It’s hard to know two legs of the triangle, but in the case described here they are known. 

[Zeke 5,504]

7 minutes ago, 10X said:

I’m more the science nerd, but I think RichP has it right, it’s only the horizontal distance that matters...though that can be hard to determine. It’s hard to know two legs of the triangle, but in the case described here they are known. 

Sin of 9.8 or 32 f/ sec^2 minus velocity and deceleration due ballistic coefficient ( wind resistance) and time?

i dunno.. your the smert one.

[Bully 749]

2 hours ago, Zeke said:

Sin of 9.8 or 32 f/ sec^2 minus velocity and deceleration due ballistic coefficient ( wind resistance) and time?

i dunno.. your the smert one.

Ouch...

You made my hed hert...

[Zeke 5,504]

2 minutes ago, Bully said:

Ouch...

You made my hed hert...

Cerebral hemorrhage 

[Bully 749]

Just now, Zeke said:

Cerebral hemorrhage 

Age.

 

And thinking.

[Zeke 5,504]

7 minutes ago, Bully said:

Age.

 

And thinking.

Ya.. don’t do that.. call me in da morning 

[vladtepes 1,060]

this was EXTREMELY helpful thats for all the info.. looking at it like a big triangle made it substantially easier to understand.. 

[Zeke 5,504]

7 minutes ago, vladtepes said:

this was EXTREMELY helpful thats for all the info.. looking at it like a big triangle made it substantially easier to understand.. 

Moar distance 

downhiill less distance.

 

[Shane45 807]

Think of it this way. If the shooting plane is flat, gravity gets to work on the bullet the entire distance. When you add angle, shooting up or down, you are effectively shortening the distance in which gravity gets to pull the bullet down.  

[Screwball 483]

Moar distance 

downhiill less distance.

 

Actually, incorrect...

 

Same distance, just less gravitational force acted on the bullet. If you have a cosign indicator on your rifle, there isn’t a positive or negative side... depending on what you get, either an angle or percentage (I prefer percentage, as it is one less step when you are calculating).

 

Example, you are shooting at a 30 degree angle... means your cosign is 0.82. If shooting at 300 yards, you shoot for 246 yards (put that in your scope, opposed to 300) That is either uphill or downhill... no difference.

[vladtepes 1,060]

well went to the range today... with some random Hornady 308 I had left over.. not even sure what grain it is.. and the gun shot well.. I know there is room to improve but all shots on target.. my wife was even able to get on the bullseye... so its a start, but I definitely need more time.. what I would like to do is use the turrets to adjust for range as opposed to holding over as I feel like it will be more consistent for me.. 

but all the info you guys gave was dead on.. shooting uphill was really no different than shooting not uphill.. I think it just psyched me out because I thought there would be some weird black magic about it.. there is not.. LOL 

 

[Eric. 9]

Vlad,

As others have mentioned, it's the exact same compensation if you are shooting up hill or down.  30 degrees up or down (for ex) is the same compensation.  It is always shorter (for compensation purposes).

Like someone mentioned, it's a cosine calc.  In a nutshell, the angle will cause you to reduce the actual calculated drop distance by a certain percentage.

Since no one likes to do math, I suggest you buy a Mil Dot Master (in addition to your rangefinder).  It's what we used before technology took over.  In addition to doing drop compensation calcs, the MDM can give you the angle and cosign calc.  Basically, you hang a piece of string or fishing line w/bb weight off it, then sight down the top edge of the MDM, to the target.  There is a scale on the side of the MDM where the string rests against, giving you the actual angle.  Once you know the angle, then you use the MDM (front side) factoring in the angle, to get the proper mil drop.  It's really not as complicated as it sounds, is dead nuts accurate and can be done very quickly with little practice.