Looking for credible articles/papers/research references for the below

[Justice1327]

1. How does a sharper shoulder angle on a rifle case help with combustion?

2. How might the surface of the chamber affect ballistic performance?

Currently reading Ammunition Demystified for the second time.

Thank you

 

[Mikecr]

I won't do a bunch of research for you, but higher shoulder angles increase powder burn in the chamber -instead of further down a bore. It holds the powder back.
A grippy chamber helps with consistent brass stretch, which affects volume of containment and bolt thrust. It holds brass forward.

 

[OG10]

Here let me google that for you…

 

[Justice1327]

I won't do a bunch of research for you, but higher shoulder angles increase powder burn in the chamber -instead of further down a bore. It holds the powder back.
A grippy chamber helps with consistent brass stretch, which affects volume of containment and bolt thrust. It holds brass forward.

I believe I know these things too, but looking for more "high level" ballistic papers/ lab results/ that have references to their criteria. for example, expand upon how a chamber impacts internal and possible external ballistics.