Originally Posted by jon.henry755
I do know that pressure inside the hollow of an arrows shaft changes with the heat of a day an will account for elevation differences on the face of a target, especially during the summer months. In competition we often would need to make adjustments for these temperature variations between 7:00 AM and noon because of the 20 degree shift in temperature.
I do not believe that changes in the air pressure inside
an arrow shaft as a result of ambient temperature change has any noticeable effect on an arrows flight path.
What the change in ambient temperature will have an effect on is the arrow's ballistic coefficient (air resistance / drag). Which can result in arrow hitting higher or lower than the conditions the X-bow (or bow) was sighted in for. If you take a look at various ballistic calculators, they usually take into consideration air density (atmospheric pressure [altitude & barometric
], temperature, and humidity).
See "Correction Factors" at Hornady's External Ballistics for examples of deviations from norm due to Higher Temperature, Higher Barometric, and Higher Altitude: External Ballistics - Hornady Manufacturing, Inc
You can see the effects of making such changes using Hornady's Ballistics Calculator: Ballistics Calculator - Hornady Manufacturing, Inc
Solely for interest:
When talking Extremely
Long Range ballistics there are also these effects on a projectiles path due to variations in gravity (flight path**, position latitude, spin of earth), earth's rotation (time in flight and direction), projectile spin (with wind - pressure difference up/down), and few others: External ballistics - Wikipedia, the free encyclopedia
** This might help explain one of the subtle effects due to gravity: The most detailed view of Earth's gravity from the GOCE satellite | Earth | EarthSky
The "force of gravity is slightly stronger at the poles compared to the equator".