I've noticed that heading west by itself regardless of temp changes still changes flight patterns.
I shot about 60 rounds each over the course of a month from my 7RM and 300RUM before I headed to WY and CO for antelope, mulie, and elk. The bullets were very consistent here. I made drop charts and taped them to the rifles.
We got to WY the day before our antelope season opened and shot our rifles for about 3-4 hours (includes MLs). My charts were trashed. The 150 Btip from the 7mag used to be 5" low at 300 with a 1" high at 100 sight in. However, in WY, it shot flatter. In fact, I popped of the first several rounds starting at 300 yards expecting them to hit between 3 and 7" low, but they were now only 1" low. I backed the target up to 100 and it was 2.5" high. This occurred on a Saturday. I shot the rifle on Thursday before we left.
Just about the same scenario with the 300RUM and 200AB.
The temperatures were roughly within 10 degrees (Casper, WY, vs. Crittendon, KY.)
The 300 rounds actually tightened up even more out west, where the 7mag 150's spread another 1" at 300.
It is rather frustrating but it is why I typically like to get to my destination 1-2 days prior to my season, so I can shoot and potentially redo a drop chart.
I shot about 60 rounds each over the course of a month from my 7RM and 300RUM before I headed to WY and CO for antelope, mulie, and elk. The bullets were very consistent here. I made drop charts and taped them to the rifles.
We got to WY the day before our antelope season opened and shot our rifles for about 3-4 hours (includes MLs). My charts were trashed. The 150 Btip from the 7mag used to be 5" low at 300 with a 1" high at 100 sight in. However, in WY, it shot flatter. In fact, I popped of the first several rounds starting at 300 yards expecting them to hit between 3 and 7" low, but they were now only 1" low. I backed the target up to 100 and it was 2.5" high. This occurred on a Saturday. I shot the rifle on Thursday before we left.
Just about the same scenario with the 300RUM and 200AB.
The temperatures were roughly within 10 degrees (Casper, WY, vs. Crittendon, KY.)
The 300 rounds actually tightened up even more out west, where the 7mag 150's spread another 1" at 300.
It is rather frustrating but it is why I typically like to get to my destination 1-2 days prior to my season, so I can shoot and potentially redo a drop chart.