Seems like there might be more data buried in the lab bomb test data (depending on what they collect).
It's just thermodynamics and the ideal gas law PV=nRT
It's really about heat calories released from the powder(which is tied to powder burned) and how much energy is in the powder. That might be something captured in the burn rate bomb tests...
The other factor is heat transmission. Different alloys/grades transmit heat differently.
Fast transmission is good because it means the barrel cools quickly...
You might have heat sensitive hands too...
That is it in a nutshell. It's all about heat. Not just heat released, but heat absorbed by the barrel throat. More powder --> more heat. The amount of powder obviously effects the amount of heat, but also the heat content of the powder has an effect. Joe Hendricks has provided a great illustration of this with his use of H1000 in the .243 Winchester. You can see the heat content for many powders in the Excel file found at
https://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/ Those numbers are taken from Quickload.
A factor many overlook is the bullet. Again, heat absorption is key. The heavier the bullet the longer it takes to engrave in the throat. The longer this dwell time, the more heat is absorbed. That is why loads that have more powder but feature a lighter bullet will usually wear out the barrel at a slower rate. And it's the key to Danzac and Moly. These bullet lubricants allow the bullet to engrave faster resulting in less dwell time in the throat and less heat being absorbed by the barrel.
