What would the upside be in “simplifying” it? At present, there’s a known set of standard ammo sizes in use, and millions of guns in existence that use them. S

What would the upside be in “simplifying” it? At present, there’s a known set of standard ammo sizes in use, and millions of guns in existence that use them. Sure, the nomenclature is weird, with a mix of imperial, metric, and just plain weirdness, but it doesn’t seem to be negatively impacting anything.