Ballistic Application Question

[RTK]

This might get long so bear with me.

Let's say I am out shooting at my favorite spot at sea level. It is 90* and I set my zero at 100yrds, punch temp, humid, bc, mv, baro pressure. I validate all my drops out to 1000yards and all is good.

The next day I decide to run up to 10,000 feet were the migration has just started. I punch in the new baro, temp, humidity, all the good stuff.

Will My drops be close enough to keep it in the kill zone to 1000 yards, short of re-zeroing and re-validating???

I have not had a chance to verify this myself, which is what I usually like to do, but in my mind it can't be even though I have been told it will be.

At both locations the program "assumes" you zeroed the gun at 100 yards (which I didn't) and I doubt the zero can be the same given the different conditions/elevations.

So has anyone verified how much the difference is??? Is it negligible??

 

[Stanm70]

Most likely your shots will be good to 4-600 yards ish. Your point of impact may alter horizontally however. The atmospheric pressure at 10,000 feet is around 3/4 that of sea level. Not to mention the relative humidity would be virtually 0 at 10,000. So there are tons of factors that would alter your shot. I would never just go out and shoot when I make a huge atmospheric jump. Most likely your shots will change drastically at 1000 yards.

 

[Broz]

Those are extreme conditions, but all I can tell you is I change altitude from 2500' to 7000' quite often and have nothing to worry about to 1000 yards. That said anytime I travel away from my normal hunting location, when I get to the new hunting location I check zero, adjust if needed (and it usually is not much if any) then send one using my ballistic app to 700 yards. If these are correct I feel confident I will be fine.

Jeff

 

[RTK]

The 10,000 feet was thrown out off of the top of my head, doubt that would actually happen to me.
I was told that with most reasonable altitude changes it would be negligible, even though I am not from Missouri I still like to verify things myself..

It would be nice if the program remembered at what temp, alt, baro etc it was zeroed at, because it is only math from that point on..........

Jeff, thanks for the hard numbers, it looks like at least a 5000 foot change is inconsequential

 

[Broz]

It would be nice if the program remembered at what temp, alt, baro etc it was zeroed at, because it is only math from that point on..........

Jeff, thanks for the hard numbers, it looks like at least a 5000 foot change is inconsequential

For $10 you can down load "Shooter" and it will let you input zero atmospheric data. And a lot lot more.

Jeff

 

[RTK]

I also have the shooter app, nice little app by the way, the only problem will all apps/programs is that when you enter new altitude data it still assumes you have a re-zeroed for those new conditions.
I would think it would be better and not that hard to ask all the parameters of your zero and do the math from there.

 

[Broz]

I also have the shooter app, nice little app by the way, the only problem will all apps/programs is that when you enter new altitude data it still assumes you have a re-zeroed for those new conditions.
I would think it would be better and not that hard to ask all the parameters of your zero and do the math from there.

Hmmm, not sure about that. Go in under the bullet, hold for edit and you can add the zero data for that load. I assumed that was for the time of zero??

Jeff

 

[RTK]

I think you may be right and I am wrong. I stand corrected.
I hadn't gone back to edit the bullet information in a while and just noticed it does ask for temp, alt, & humi etc. in that section and also in the main page.
Wonder if it distinguishes, remembers and does the math...............Hmmm

 

[BrentM]

It does remember. I had set my load at 4200ft, 10F, and baro for the day. I used this all winter and into the spring. My elevation was dead on all the way to 1500 yards.

I don't use Altitude anymore. I do use absolute barometric pressure though. It works very well and has not let me down yet. For example when I shot the 160 matrix loads I was shooting at 25 abp and 59F. The rifle was zero'd at 200 and 2850 fps used as the velocity. I don't use the powder temp. I would leave this in my iPod as the go to Hard coded info for the bullet unless I re-zero for some reason somewhere or sometime else. I can also go in and select my 140 VLD and just re-zero my turrent. I have a note in the comments section that says .75 MOA down from 160 zero. I dial .75 MOA down and that is my zero for the 140. I took that out to 1000 last weekend it was dead on.

Shooter makes me giggle. I almost feel like a shooter. LOL