Slightly OT, and most of these catalog pages are probably courtesy of Dave

The H&R Model 1900 was available only in 12g on introduction, but 16g, 20g and 28g were added shortly thereafter

The Model 1905 was available in 24g

[Linked Image from photos.smugmug.com]

As was the Model 1908

[Linked Image from photos.smugmug.com]

As was the Model 1915 "Small frame"

[Linked Image from photos.smugmug.com]

Which about 1931 became the "Standard" No. 5; still with 24g

[Linked Image from photos.smugmug.com]

I don't know how long the 24g was offered