NRA did a lot of experimentation in the 1960s, and they found that much depended on rifling design, throat geometry as well as land diameter and groove diameter. https://www.castpics.net/subsite2/Cl...tBullets-s.pdf
In the 1960s, many shooters were using 2-groove barrels, which like a very different bullet from 4- and 6-groove designs. My K31 rifles with their non-existent throat where the rifling comes almost back to the case mouth take very different designs from commercial normal throat and military very long throat. My experience with commercial barrels has been that they have larger-than-standard groove diameters, and if you shoot a cast bullet intended for standard in a larger barrel you'll get world class Leading. Lube does make a difference, and I still use mostly NRA formula.

If you want the easy button for .30 caliber, except for the K31, the gas checked Lyman 311291 or 311284, sized to at least .310", and seated such that the bullet is marked by the origin of the rifling.