BTW, rimfire brass is produced by drawing a disc of brass sheet over a progressive set of dies. Centrefire needs turning on a lathe and all sorts.
Center fire and rim fire both start life as a brass disc.
The punching and forming process are very similar, but the larger and thicker brass for a center fire requires more material and more stops.
There is a very little bit of turning on some center fire cases fir extractor groove, and while a few companies drill flash holes, most are pimply punched.
A lath us not used for the cutting, but special built high speed machinery.
A rim is created on rim fire brass by a process called 'bumping.'
A mandrel is inserted into the partial formed case almost to the bottom.
The bottom of the case is then forced ('bumped') against a shaping die that forms the uniform rim.
It is a real PITA to set up the equipment, but once it is running correctly the cases just pour off the line.
Center fire brass if similar but often requires annealing steps for larger cases to prevent over hardening during drawing and forming.
Forming the case head for high pressure cartridges takes some careful work to make sure they are hard enough by the end of the process since the starting brass is not very hard t allow it to draw and form correctly.
