Zero change in relation to elevation.

[cgarb]

If i zero a weapon at 1500ft and drive to hunt an 8000ft elevation and do not have an opportunity to check zero is there a way to compensate for that though calculation? I know it will effect my dopes and the ballistic app will change that with the program, but the zero of the rifle wont be in that equation. Idealy i know i would like to shoot to verify but what if you cant? Snipers cant pop off a few practice shots before the real deal so somehow this must be practical.

 

[royinidaho]

My 'personal' experience, keep in mind I'm not an "expert" driver has been:

With a 100 yard zero I, again personally, haven't seen enough difference between 4488' ASL and 9600' ASL to make a difference.

With a 300 yard zero I , "May have" seen some difference but not enough to make me panic.

So far, as far as I'm concerned it the down range trajectory that concerns me most.

This coming, spring and summer activity will provide more evidence.

 

[Shane Lindsey]

You should be able to program the elevation you zero into the app. Take note of the correction and then plug in the elevation to hunting elevation. In your case you zero at 1800 and then change to 8000.

I plugged in one for a 30-06/175 gr LRX at 2775 fps muzzle vel and at 500 yds it gave 10.3 MOA at 1800 ft and 9.5 MOA at 8000 ft.

We used to use 1MOA for every 2500 ft of elevation. 1MOA for every 20 degree temp change. That was with a 173 gr M118 Special Ball round at about 2650+- fps. I think that is a little off based on the newer applications, but it worked for us (SWAG at best).

Really dependent on vel/BC/etc.

 

[cgarb]

In theory then i should sight in low. Then when i get to the high elevation i should be on target. I wish i had somewhere on the east coast to shoot at 8000ft...that would make my life a lot easier. If I wasnt married with children I would just move to wyoming then everything would be good.

 

[Barrelnut]

If I wasnt married with children I would just move to wyoming then everything would be good.

Maybe they would want to go with you.

Like Shane said you can account for this in an App like Shooter or Applied Ballistics.

You enter the current elevation, temp, humidity, and pressure at the time when you zero the rifle. In you case 1,500 ft. The when to get to 8000 ft., you just enter the current info for the shoot and it takes care of things in the calculation. I shoot from about 200 ft to 6000 ft. and it seems to work. Note: You do not need to change the zero atmospherics, used during zero. They alway stay the same and are a parameter of the bullet and load stored in the App.

Hope that makes sense.

 

[cgarb]

So what you are saying is that if i use the balistics app and change elevation in there the app will include the difference in drop plus the change in zero and that will be good data to just use as displayed? So then the only place my gun would not hit dead on would be the actual zero distance 200yds (example). Provided no human error...lol

 

[Barrelnut]

You got it!

 

[cgarb]

Ok...thats way easier than I thought. What would we do without electronics. Thanks.

 

[Shane Lindsey]

You SWAG it...

 

[cgarb]

If you want a good laugh go look SWAG up in the urban dictionary...lol.

 

[Shane Lindsey]

Well I guess I meant to say Wild *** Guess it...

 

[kcebcj]

If i zero a weapon at 1500ft and drive to hunt an 8000ft elevation and do not have an opportunity to check zero is there a way to compensate for that though calculation? I know it will effect my dopes and the ballistic app will change that with the program, but the zero of the rifle wont be in that equation. Idealy i know i would like to shoot to verify but what if you cant? Snipers cant pop off a few practice shots before the real deal so somehow this must be practical.

In QuickLoad you can sight in at 1500' elevation with that atmosphere data then retain that info for the 100 yard zero. Then you can generate a drop chart with different atmosphere data let's say at 8000' using the sight-in data for the zero and the other data for distance. It adjust for the difference. I hope you get what I'm trying to get across? The zero is critical for an accurate drop chart especially if you have not proven it on a hunting trip at altitude.

If you take a rifle zeroed at 100 yrds at 1500 feet to 8000 feet it is no longer zeroed at 100 yards. Not off much but its off.

Seems there are other ballistic programs that do that same thing just can't recall.

 

[cgarb]

I assumed thats what you meant also...i just thought it was funny.

 

[HARPERC]

If you want a good laugh go look SWAG up in the urban dictionary...lol.

Yeah things change......

I may have missed it, but have you validated your data at your present location?