Just before the men walked on the lunar surface, these were being marketed as duck guns, through the efforts of one Francis E. Sell:

[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]
[Linked Image from i.ibb.co]

As late as 1977 (Gun Digest, “The 20 comes of age” Francis E. Sell) 20 gauge 3” guns were being marketed for duck and goose hunting. Mr. Sell had some connection to Richland Arms, of Blissfield, MI. in the late 1950s to about the late 1960s. They imported Spanish and a few better quality Italian guns, and the Italian guns had internal barrel dimensions to Mr. Sell’s beliefs, long forcing cones, overbored, long chokes and 3” chambers, along with a hidden third fastener. If waterfowl hunting had not been mandated non toxic shot only, the guns may have been more successful. The example, above, is unused, but, most of the guns I have seen were run pretty hard. You also got some hand engraved scroll, bone color case hardening, and nice Italian checkering. Prices floated around $150 in 1968. It is worth noting that for whatever reason, by the 1977 article, Mr. Sell was using other, more expensive 20 gauge 3” Italian guns, with identical bore dimensions, for his duck and goose hunting.

Another point, the Spanish versions of the Richland offerings from the same era, leave a bit to be desired. Not sure whose idea it was, but, they are often seen with a cheek piece.

Best,
Ted