100,000
I can say that Browning started having shotguns made in 16 gauge in the year 1909.Winchester started having the model 12 shotguns made in 16 gauge in the year 1914.so I would surmise that the time frame of 1909-1915 would be the correct time frame for the introduction of the 16 gauge shotguns.
Ithaca made 10 gauge shotguns.
Crescent
Yes, they were made.
Rifles are referred to by caliber. Shotguns are referred to by gauge.
Browning, Remington
One might recognize the two names Browning and Remington. They still make 16 gauge shotguns, as do a few other manufacturers.
75-100 yrs ago
1880s to 1940s
The answer to your question is Yes! 16gauge shotguns and shotshells are still made.
Utility grade made @ turn of the century
about 200 dollars