7.62×39mm and 5.45×39mm aren't "calibers," they're "cartridges."
...Because of its caliber, the 12 gauge shotgun....
And 12 gauge is a gauge, not a caliber.
The best thing about writing for American Shooting Urinal is that there's absolutely no pressure because no matter how bad a day you're having at the keyboard, no matter how crappily you write, you can't possibly diminish their prestige (because they're already as bad as it gets).
I have a penchant for all things AK, I have all calibers and gauges.
Kalashnikov was a genius