There's no saying what will or will not shift in different conditions.
Temperature can affect your rig in 3 main ways.
1) Your scope can change it's ranging, ranging short or long, and different scopes behave differently at different temperatures
2) Your gun can change speed, producing more or less power, thus affecting the point of impact down range
3) Your gun can warp, changing shape, forcing the barrel and scope to point differently to each other than at a different temp.
2 & 3 can be engineered to to a good extent, but you need to prove it in order to isolate it. 1 can't. You need to learn it.
Best way to find out what is doing what is to work on a fixed distance target that you can approach under different conditions. You need to be objective and do this work for yourself, not assume that someone else's work will match yours... it may, or they may have borrowed it off the internet off someone who actually had another problem.
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep