I'm pretty well known around here for my full tilt work ups, IMR-4350 has been a long time powder of choice I used for .270 win, still use it, and I use 130 gr. projectiles nearly exclusively. So maybe I can shed some light on this, though RC pretty much covered it all in a nut shell.
Depending on the brass, which makes a major difference regarding pressures, I run a load of between 54.0 grs. and up. I won't specify the max charge I run, lets just say I do push the ragged edge, yet still within published data. IMO, the single most common pressure factor to be considered with high pressure bottle neck cartridges, is the brass.
Now to address the effects of temperature. I lived in N. Az. for about 7 yrs., so winter temps would often be well below freezing, any where from 5 or 10 degrees, to low 40's. Then after moving back to the S.W. portion of the state, summer temps would very commonly run triple digit, 100-115 degree's. This said, I think it's safe to say I have experienced both ends of the spectrum and can provide realistic assessment, with my rifles, brass, and seating depths. Since I also usually seat up to, or into the lands, the effects of temperature are often very noticeable.
So, with max loads that had been worked up in the cold weather, that when fired in temps at or above 100 degree's, I did experience some obvious, multiple pressure increases. Signs of excessive primer flow, bolt face / extractor button transfer marks, an obvious increase in velocity, and stiff bolt lift were all very discernible and present.
And in cold weather, the loads that were developed in very warm weather displayed some very obvious and multiple signs of significantly lower pressures. Collapsed shoulders, decreased velocity, gases blowing back over the shoulders were all present.
All my finding were assessed using multiple methods, including velocity (chrony), case head appearance, primer flow ( I only use CCI's), and bolt lift.
BTW, without looking in my log book, I may have the temperature effects reversed. It could be that I experienced higher pressures with high temp developments being fired at extreme low temps, and low temp developments producing lower pressures in high temps.[/B] But unless my recollection is flawed, and it could most certainly be, but I'm fairly certain I had it right the first time.
All this said, it's always best to develop loads in, and for the temperatures you intend to shoot them in. And as I mentioned, use matching head stamps, sorted by weight when possible to avoid large variations. If matching head stamps are unavoidable, then at least try to sort them by wight.
GS