Question about high altitude shooting

[elkaholic]

Just a follow up, cause I did the math. ( Correctly, I hope. )

For a 647 yard shot at a target 200 ft higher. That equates to an angle of only +5.9 degrees. That changes the true overland distance of the target to 643 yards. That only changes the point of impact by 1.3 inches.

To have a 30 degree angle to the target from 647 yards, the target would have had to be 970.5 feet higher.

200 ft. sounds like a lot, but when it is 647 yards away it is not. So, the only true impact of the altitude change is the 10 inches less drop. That equates to 6 ft total drop from a 1" + 100 yard zero.

With a target 200 ft. higher at an altitude of 8600 ft. the shooter would of had to holdover 6 feet to make the shot.

But then how do you know it was 200 ft and not 970 ft.? It is hard to judge. That is why I use a range finder that gives me the target angle too.

I guess I missed the 200'!

 

[6mm06guy]

Just a follow up, cause I did the math. ( Correctly, I hope. )

For a 647 yard shot at a target 200 ft higher. That equates to an angle of only +5.9 degrees. That changes the true overland distance of the target to 643 yards. That only changes the point of impact by 1.3 inches.

To have a 30 degree angle to the target from 647 yards, the target would have had to be 970.5 feet higher.

200 ft. sounds like a lot, but when it is 647 yards away it is not. So, the only true impact of the altitude change is the 10 inches less drop. That equates to 6 ft total drop from a 1" + 100 yard zero.

With a target 200 ft. higher at an altitude of 8600 ft. the shooter would of had to holdover 6 feet to make the shot.

But then how do you know it was 200 ft and not 970 ft.? It is hard to judge. That is why I use a range finder that gives me the target angle too.

That's where I'm not sure, my rangefinder will calculate the angle and compensate, but it doesn't tell me the angle. I don't even have a picture to show you where the animal was a few hundred feet is just a guess. If it helps I was shooting off of a Harris bipod that is 11"-29" tall and I was on the short side shooting up.

 

[elkaholic]

That's where I'm not sure, my rangefinder will calculate the angle and compensate, but it doesn't tell me the angle. I don't even have a picture to show you where the animal was a few hundred feet is just a guess. If it helps I was shooting off of a Harris bipod that is 11"-29" tall and I was on the short side shooting up.

So you are saying that "647" WAS the corrected angle??

 

[6mm06guy]

So you are saying that "647" WAS the corrected angle??

Should have been, I can't double check, because on the way back to camp, my light died, and we'll I lost my range finder in the dark... it was a rough trip.

 

[elkaholic]

Should have been, I can't double check, because on the way back to camp, my light died, and we'll I lost my range finder in the dark... it was a rough trip.

If that's true, we are back to 10" for altitude!

 

[6mm06guy]

If that's true, we are back to 10" for altitude!

I'm not going to sweat it to much, you have helped alot. And I know better for later. In the end I bagged my elk with 2 clean hits. It wasn't pretty but I got the job done. If you are interested there's a pic on the trophy page.

 

[Alex Wheeler]

OP, your missing something. The scenario you describe is not possible and 100 yard zeros dont change with altitude. My guess is you finally found a hold that allowed your rounds to bounce off the ground and hit the animal. Sorry, after you realize you have no idea where to hold you should stop. Just glad that elk didnt end up 5 miles away with a gut shot. Thats the stuff that gives long range hunting a bad wrap.

 

[SHRTSHTR]

I just got back from Colorado where I killed a 4x4 bull at 647 yards. My question pertains to my rifle. I'm using an 8mm rem mag with 200gr accubonds at 3000 fps. Whats weird, probably because I have never shot at a high altitude is I had to put my cross hair right on the animal to score a hit. zero drop at 647 yards. It boggles my mind. I drove home to Missouri and double checked my zero, still dead on. 1" high at 100 yards. The accubonds bc is .450, even at altitude it should have had like 30+ inches of drop, and if not I need a new ballistic calculator. Or would my zero be higher at 100 at elevation?

any advice?

Have you considered hunting in Kalifornia? I hear there's big Elk's down that ways. Don't forget to take a couple 10 round magazines for those 7-8mm rifles.

Ray

 

[Switchback2]

This is why it is Best to have a Ballistic App you have proved to work for you, So when you go from 800 ft to 8600 you can input all the correct data before pulling the trigger so its not a guessing game.

 

[Mike 338]

Should have been, I can't double check, because on the way back to camp, my light died, and we'll I lost my range finder in the dark... it was a rough trip.

Ahh yes, that's what adventures are made of.

Just about the time you learn it all, your so old and broken down your no use to yourself or anyone else. Your do'in fine. Just keep ask'in the right questions and adjusting appropriately. You'll know so much, nobody will want to talk to you.

I'm like'in this thread.

 

[6mm06guy]

Ahh yes, that's what adventures are made of.

Just about the time you learn it all, your so old and broken down your no use to yourself or anyone else. Your do'in fine. Just keep ask'in the right questions and adjusting appropriately. You'll know so much, nobody will want to talk to you.

I'm like'in this thread.

Thanks mike. My dad always told me the people who are the best weren't the best because of skill, they were the best because they made more mistakes than everyone else.

 

[Mike 338]

That's where I'm not sure, my rangefinder will calculate the angle and compensate, but it doesn't tell me the angle. I don't even have a picture to show you where the animal was a few hundred feet is just a guess. If it helps I was shooting off of a Harris bipod that is 11"-29" tall and I was on the short side shooting up.

Everybody needs a back up plan.

Stick your fist straight out at 90 degrees, so it's basically a level. Now rotate that fist down. For every "fist" you go down or up, that's 10 degrees.

Not say'in you need to do this but before I go hunting, I go to JBM website and run a drop chart for the anticipated altitude I'll be hunting at with a print-out of every 10 degrees of angle. Angle of shot is pretty darn important, unless your hunting in your living room. Anyway, it may take a couple of seconds extra to find the right chart but you should be close if you, more or less got the altitude, temperature and angle correct for each chart. It's darn sure better that shooting 10 times and guessing what the heck is wrong with what your do'in.

 

[venatic]

You didn't happen to range from the fallen elk back to where you were shooting from?
I ask because my guess at what happened was your Rangefinder gave reading beyond the elk and he was closer than your RF Number gave you.
Just a thought.

 

[6mm06guy]

You didn't happen to range from the fallen elk back to where you were shooting from?
I ask because my guess at what happened was your Rangefinder gave reading beyond the elk and he was closer than your RF Number gave you.
Just a thought.

No, I didnt. I lost it going straight down hill though the thick oak brush. Gives me an excuse to get a new sig 2400 I guess.