I have read on numerous occasions the .30-30 was introduced as a black powder cartridge, based solely on the name designation. This is however false. First Win did not name it the .30-30 but as Fox correctly said the .30WCF (Winchester Center Fire). The .38-55, .32-40, .30WCF, .25-35 & .32WS are all based on the same basic case. Had the .30-30 been a black powder cartridge its capacity would have been between the .32-40 & .38-55 so it would have been on the order of a .30-45 to .30-50.

There has been much controversy over the "Reason" for the .32 WS. Dave Scoville of "Rifle/Handloader magazine a few years back published a statement made by Winchester themselves at the time of its introduction.

They stated Flat Out that there were many people of the day who desired to be able to obtain higher power smokeless factory loads for some of their shooting but to also be able to reload with black powder for a less powerful load for much of their use. The .32 WS was deemed the best size for this purpose. The caliber was upped from .30 to .32 but same weight of bullet was kept @ essentially the same power level. Twist rate was changed from 12" for the .30 to 16" for the .32 which was much better with the black.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra