Changing point of impact and group size when traveling

[Len Backus]

When we travel to another locale across the country we know that the point of impact at 100 yards of our favorite accuracy load may change and we usually re-sight our rifle to local conditions. Going one more step, the traveling long range hunter arriving in the western mountains should check his bullet's drop out to 500 yards or more to check the result of ambient temperature and altitude on the ballistics. Have any of you also come to expect that the group size of this favorite accuracy load in your rifle may change as well?

While never having tried to re-check my group size after traveling, I have had a couple cases recently where a newly purchased rifle was sent to me from over a thousand miles away accompanied by the rifle-builder's own worked-up accuracy load data. In both cases, I was unable to achieve similar accuracy with these loads but I was able to achieve it after modifying the loads for use at my locale.

This makes me wonder if my ½ moa rifle is no longer that when I travel west. Any thoughts?

 

[Guest]

A friend of mine here in Va. went on a prarie dog shoot somewhere warm,might have been Arizona. When he and his friends started shooting they were not doing as well as expected. After some thoughts about the temperature change they tried putting their ammo in the cooler, they all noticed significant improvements in accuracy. I know a few competition guys who load their ammo partly based on what the temperature will be.