Thanks Daryl,
I had neglected to add the expanded explanation re: PO Ackley experiments. I have forgotten the approximate number now, but modern solid head cartridge brass also will hold the pressure and not stretch at the web up to something like 45,000psi. “Most” of the early rifle rounds did not exceed these pressures.
As well, “most” of the early Double Rifle and Single Shot rimmed cartridges had/have straight walls with minimal taper so they will, if not greasy or oily, stick to the chamber walls rather well.
Side note: British proof was done with oiled cases in order to give the worst case breech face pressure.
You can see or feel this phenomenon in checking the primer after firing…..it will be just pushed out from flush with the case head where the cartridge gripped and didn’t get pushed back tight against the breech face.

- Mike