Hmm. I work with words, and have learned some stuff about it over the years.
If a lot of people say "caliber" for "cartridge," then that's common usage. Someday soon caliber will probably be dictionary-listed as a synonym for cartridge.
Best description & explaination...as usual.
In the South, caliber & cartridge are used interchangeably and I hear caliber more often than cartridge.
Jerry
