I would like to find out from some of you guys what experiences you have had with chronographing identical loads at varying altitudes. The reason for the question is pretty straight forward.#1- Does altitude have a large effect on velocity at the muzzle ? If so, how do you correct for changes in altitude without a chrono ?( are you guys dragging your chronos with you on every darn hunting trip ? ) #2 If you input a certain velocity value into your ballistics program Does it automatically crank up your velocity reading a determined amount when you input into the software , say for example , a simple increase in altitude ? In other words when I input all my parameters at 2600 ft ( home ) elevation with of course my chronographed velocity and then go hunting at 7500 ft , does my software calculate a new muzzle velocity based on my new elevation or is it simply telling you what that bullet will do at the new elevation based on my original 2600 ft velocity ? I have to believe that higher elevations will produce higher " MUZZLE " velocities , I don't know!