America's most popular firearms and their ammunition

[ChalkLine]

I've been having no luck in finding out what the most popular handguns and semi auto rifles in the US. I want to know this as this will dictate what the most common ammunition remaining is.

I've read some articles which are confusing, but it's pretty obvious the AR-10/15 is heads up letting me confidently assume* that 5.56 x 45mm is the most popular and this seems to be followed by the venerable 7.62 x 51mm is at least equal. After this I just don't know enough about the US to guess.

Shotguns are comfortably 12 gauge with other far behind.

Pistols are where it gets murky. Some years ago I would have confidently stated that 9.0 x19mm was everywhere but since then .40 cal round has been making headway. Couldn't even guess after that.

(*there's that word)