Shooting downhill and POI?

Savage cat

Savage cat

New member
I'm having a hard time finding a place to sight in my rifles. The only places I have are shooting downhill into ditches, so how much will my poi of impact change if I sight in shooting downhill then shoot at something on level ground? I hope this makes sense. It's not a very steep downhill angle, or am I just worrying about something that doesn't matter? Thanks
 
You need the angle up or down and the cosign for that angle mutiplied by the straight line distance to the target.

Remember the wind values are constant on the straight line distance but the gravity effect is what your angle figure determines. You could conceivably have a 500 yard windage shot but a 350 yard elevation shot.

Math is your friend. If you can put the math on the gun you can make any shot given the AO of the cartridge.

Greg
 
Originally Posted By: Savage catI'm having a hard time finding a place to sight in my rifles. The only places I have are shooting downhill into ditches, so how much will my poi of impact change if I sight in shooting downhill then shoot at something on level ground? I hope this makes sense. It's not a very steep downhill angle, or am I just worrying about something that doesn't matter? Thanks


How far?

Are we talkin' 100 yards or 1000 yards
 
Originally Posted By: Savage cator am I just worrying about something that doesn't matter? Thanks

unless the distance is a long ways, like over 400 yards, it doesn't matter a whole bunch.
 
It doesn't matter unless the angle is extreme. If you are 50ft above the target and you want to sight in at 100 yards, set your target at 101 yards away with your range finder. If you are 500ft above your target and you are shooting at 1000 yards set your target at 1010 yards with your range finder. Its getting late I hope my math is right.
 
Uphill or downhill you will hit high. Los in anything but level shooting will be greater than the true horizontal distance, which is what the bullet 'cares' about. If youre good at internal imaging its easy to compensate, you aim for the horizontal not the los. But unless either the angle or distance is extreme, it doent matter much for hunting. Clear as mud?
smile.gif
 
Originally Posted By: jlh321It doesn't matter unless the angle is extreme. If you are 50ft above the target and you want to sight in at 100 yards, set your target at 101 yards away with your range finder. If you are 500ft above your target and you are shooting at 1000 yards set your target at 1010 yards with your range finder. Its getting late I hope my math is right.

Sleepy or not your math is very good. You can do it with the Pythagorean Theorem but the cosign is much quicker.

Greg
 
This is only going to be a hundred yards, I'll be sighting in my 243 with 87gr vmax. And where would you zero the rifle in at? Dead on at 100 or 200 and how high should it be at 100 to get a 200 yard zero? Sorry for all the questions.
 
If you zero at 200, you'll likely be 1 to 1.5" high at 100 yards. It obviously depends on your specific load, but that's pretty typical. If you zeroed at 200 you should be able to hold dead on for anything inside 200 yards.
 
Originally Posted By: kpkieferIf you zero at 200, you'll likely be 1 to 1.5" high at 100 yards. It obviously depends on your specific load, but that's pretty typical. If you zeroed at 200 you should be able to hold dead on for anything inside 200 yards.

I stumbled across and learned mpbr shooting for hunting years ago, I refuse to go back!

For elk sized targets with my old rifle, dead on from muzzle to 424 yards. Deer and goat, shorter range but still a second with the laser to confirm distance, pull the trigger and start field dressing. Doesn't work for target shooting though. But it does do away with worrying about uphill downhill and if you hunt terrain, 1 less thing to worry about.

And this year I'm running a new caliber so I have to start the math sometime, a bit more arch to the ballistics.
 
Don't know velocity, I'm trying to find a spot to run some test loads and get the gun sighted in. Thanks for all your help fellas!
 
Originally Posted By: Wedgy

You are only shooting the "4" as far as gravity is concerned, not the "5"

But you are shooting "5" of wind. That will bite you in the mountains at acute angles.

Greg
 
Subtracting 1 percent from the line of sight distance for each 2 degrees of angle (up or down). 300 yards to target 10 degrees down angle(5 percent)= 15 yards, hold for 285. To sight in at 300 place target 315 yards.
 


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