If you're gong to go apsh!t on a [admittedly basic] question, I'd use "Chamberings" instead of "calibers" as the book diameter of .30-30 bullets is .308.
Yes, OP asked a basic question. But, better he ask, than have an oopsie.
I've been involved with guns for significantly more than 10 years. I still learn stuff. Hell, last summer I found a cartridge in a chambering I'd never heard of, .401 WCF in the mag of a Winchester .30-30 lever gun.
Guy brought a 94 Winchester to me with "A bullet stuck in it," and asked me to help. Wrong cartridge had been stuffed into the loading gate, and was not in a mood to come out. Seems that .30-30 is not the same as .401 SLR This oldie was a new one on me. I don't count myself as an expert, but...
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