With Doctor: Atmospheric Effects on Precision and Ballistics

Описание: The rifle shown in the thumbnail for this video is the late Dr. Jeff Yost. Jeff was a kind soul and short-range bench rest record holder. His presence at matches will be missed.

The purpose of this testing is to conduct an open-ended examination of the effects of atmospheric variables have on precision and ballistics.

Conclusions
The data support the theory that atmospheric conditions determine the precision and affect ballistic performance. The atmospheric conditions may show distinct cut off values where the precision degrades considerably if you continue to use the same load after you have passed the cut off value. This test indicates that station pressure has the largest impact on precision and indicators of air density (i.e., humidity and temperature) determine bullet velocity and have an interactional impact on velocity.

Recommendations
Given that atmospherics play a role in precision and ballistics, I emphasize that shooters pay close attention to atmospheric effects wherever they shoot regardless of shooting discipline or purpose. Without an understanding of how atmospherics affects precision and ballistics, you are likely to underperform and lack the ability to explain the outcomes of your shooting. By understanding atmospheric effects, you can make either precise or “best guest” estimates of when and how to adjust for the atmospheric conditions which will improve your precision and confidence in your ability to perform well. Also, you can develop strategies for how to cope with variations in atmospherics.
Practical Implications
There are several practical implications to these findings including:
1. Pay close attention to atmospherics by examining details of the current conditions and forecast;
2. Be prepared to adjust a previously developed load (If you are preloaded, tuners are helpful for this type of situation because you can take preloaded ammunition and tune it to precision; if you are loading at the match, having a couple options for different powders and bullets could be helpful or, ideally, find a load that works in low station pressure conditions);
3. Assess velocity in the current atmosphere so that you have an accurate velocity to input into your ballistics software;
4. Check your ballistics calculator to see if it allows you to enter atmospheric variables such as humidity and temperature in relation to velocity measurements. Also, check to see if the software will calculate expected adjustments to ballistics within differing atmospheres;
5. Be prepared to make an “educated guess” if you cannot do any of the strategies outlined above; and
6. Conduct testing similar to this to assess the impacts of atmospherics in your particular part of the world. This will help you understand what is important in your particular region.