I noticed the sequential numbering on the shell casings in #8.
It reminded me that in at least one German high-intensity gun (Paris gun?) the projectiles were sequentially forged and numbered, each slightly bigger than the last, to compensate for wear in the barrel.
There was also a centrifugal machine gun tried out by the US. Ball bearings were fed through a hopper to a rapidly spinning impeller, which threw them out the exit port at "high" velocity. Not adopted because of the power needed to run it among other things. (Yeah, I know, centripetal vs. centrifugal, blah-blah.)