If the elasticity of the brass provides a good gas seal all is good, and apparently your experience suggests it is, I haven't tried it myself. That fact that you only got a single use out of the brass might be a red flag, and was a note of caution to me. I would have thought that once the .30-30 brass assumed the shape of the .303 chamber, it would have stood several firings without failure provided it was resized in a .303 Savage die. I don't know if the dimensional differences between the two rounds are any more extreme than is the case of a number of wildcats which require fire forming to make the brass the correct dimensions.
By the way Doug, I miss your participation as well.
It's not that you only get a single use out of it that you throw them away. It's because you acknowledge the difference in the web thickness that does not expand during fireing. It's just safer to throw away plentifull once fired 30-30 cases & not risk the web letting go on the 3rd, 8th or 25th fireing!
It's not like the 303S is a varmint or range gun that's fireing many times a yr.
For mine once ever few yrs I take it & remind myself how good a deer slayer it is![]()

I have fired low-pressure loads several times without incident, but it's not worth the bother.
Do you mean with 30-30 brass?
I fire full power loads with 170gn bullets, in other words the old 303 equals the 30-30.



























