Atmospherics at 100 yd Zero important ?

[njaimo]

Hi There;

Have worked my way through Bryan's books (Applied Ballistics 2nd Ed. and Accuracy and Precision for long range) and wondering how much impact in firing solution does the atmospheric conditions during rifle zero make. Say I zero my rifle scope during cold winter weather (dense cold air) and then use it to shoot in 20C warmer weather in Spring or Summer. None of the ballistics software I have seen ask for atmospheric conditions during zeroing, so I assume the effects are negligible ?

I suppose I may be told I need to re-zero at the approximate conditions I will be shooting at, but I do not have easy access to an accurately measured 100yd range -- which is another issue I am trying to figure out how to get done without fancy GPS or a 100yd steel tape which seems hard to find these days.

It would seem, a ballistics program could easily enough take into consideration the conditions during Zero when calculating a firing solution at other conditions...

...or perhaps I am missing something ?

Many thanks in advance for any pointers...

Cheers!

 

[mr45man]

http://www.shooterapp.net/
This one does
John H.

 

[njaimo]

...ahh ! Many Thanks !

Cheers

 

[CharlieNC]

Remember the difference in ammo temp can also make a significant velocity change which you must account for.

 

[savageshooter86]

I use the Shooter app. Works well

 

[DWalt]

Also http://www.jbmballistics.com/ will work by changing atmospherics. The Zero shift seen with increasing atmospheric temperature at 100 yards will be inconsequential between, say, 32 F. and 80 F. However the PO! shift will become much more evident at higher temperatures and longer distances using the original 100 yard zero setting,

 

[njaimo]

...many thanks to all for the replies -- clearly I had not looked close enough at the ballistic apps (noticed too AB has Zero atmospherics as well).

Cheers!

 

[DocUSMCRetired]

Atmospherics on a 100 yard zero do not matter. However our apps do allow you to input it. It is more important on long range zeros. I wouldn't waste my time with atmospheric data on a 100 yard zero, it has no impact.

 

[Bryan Litz Ballistics]

I agree with Doc.

The Shooter and AB Mobile apps allow you to account for atmospherics of your 'zero', but this is only necessary when using a long range zero.

Atmospheric effects on 100 yard zeroes are almost always under a click.

I suppose if your rifle's POI was sensitive to humidity (wood stock not pillar bedded) or heat, then your zero might be affected by atmospherics, but this isn't an external ballistics effect that can be modeled.

-Bryan