Some 20 years back, a local gunsmith mentioned loadin his .45 to .44 Mag behavior. My jaw dropped. He explained that the issue of "old cases" and high pressures is legit if you have some of the ancient, folded head brass. With modern manufacturing, that concern no longer applies.
I'm not saying, here, that you could load to .44 Mag pressures. But, with 300-grain bullets you can get near to .44 Mag velocity at a lower pressure.
Once again: At a given pressure, the larger-diameter bullet goes faster. At a given velocity, the larger bullet gives lower pressure.