I’ve long suspected the major reason steep-shouldered cases don’t “stretch” much is when correctly sized they headspace more firmly, so don’t get pushed into the chamber slightly deeper by the firing pin, as can happen with slope-shouldered rounds. This is even true of the .22 K-Hornet, because the new shoulder headspaces more precisely than somewhat variable Hornet rims.
Yes, I have found a press fit works quite well in target rifles - both rimmed and rimless. We often measured the chamber on competition rifles, so we could return the cases to a precise fit. Of course, in hunting or standard issue military rifles, you wanted a few thou of play inside.
WRT to the 303 or other rimmed cases that headspace in the rim recess, I have seen rifles with long chamber issues. Some gunsmiths and shooters mistakenly thought they had headspace problems because the cases would stretch or split. They were thinking rimless when they should have been thinking rimmed. They saw the classic stretch band, forward of the rim. In fact, the headspace was fine, but the chamber was long.
There was also a problem that happened occasionally with older rifles that were chambered for rimmed cases. This occurred when headspace was moving toward, or was excessive.
The firing pin would kick the cartridge forward several thousandths of an inch until the rim contacted the front section of the rim recess and stopped. The powder would burn and pressure would push the head backwards until it contacted the bolt face. The case would stop - jammed if you will - against the bolt head. At the same time, the longer chamber in front of the rim recess would allow the brass to stretch forward to fill the void.
The very steep 40-degree shoulder of Ackley Improved rounds isn’t necessary, as I’ve seen this in any case with a shoulder around 30 degrees. Neck-sizing helps reduce stretching, but steep-shouldered rounds seem to resist stretching even when full-length sized—or do when FL sized correctly.
Which is why I like the rimless 303 - aka as the 308 Win. It only has about 4 more degrees of shoulder, 20, compared to 16 for the 303, but combined with the thicker case walls and reduced taper, it works. It is a very efficient, no nonsense cartridge. The taper is approx. 16 thou for the 308 vs 55 thou for the 303. Stretch is reduced and you can get a better fit.
It also helps that chamber reaming is more consistent these daze too.
The last thing - especially for older firearms - is the lack of consistent chamber sizes. This can play hell on rifles firing rimmed cartridges especially. Hence the reason to find the correct fit and return the brass to this conformity - but only with target rifles.