Weather factors

[Cut]

Temperature and barometic pressure can greatly affect the long range (over 1000 yards)shots. How much of a factor is it on smaller caliber rifles, such as .308's and .300WM?? Humidity, ammo temperature, barometic pressures any of these need to be considered?

[RifleMaster]

Hi Cut,

Certainly changes in air temperature, barometric pressure, and humidity will affect long range bullet flight. An increase in air/ammo temperature will increase muzzle velocity. There is a rule of thumb to follow. A 10 degree change (increase or decrease) will cause Match ammo to impact one minute (10 inches) higher or lower at 1,000 yards. A decrease in barometric pressure at higher altitudes will cause bullets to retain more velocity at all distances because of the thinner air. Significant increases in humidity makes the air thicker/heavier and causes bullets to loose velocity.
I believe Trigger50's book covers these subjects.

Keep hold'em hard!

Carl/RifleMaster

[Cut]

Thanks Carl, thats were I got the question from. I've been neck deep in the HTI book since I got it. Now I have to bust my piggy banks to get a .50.

[RifleMaster]

Cut,

Most exterior bullistic programs have corrections for altitude, humidity, temperature, etc. The Sierra Infinity program has them.

Carl/RifleMaster

[This message has been edited by RifleMaster (edited 03-20-2000).]