Reverse chokes

[Mike of the Mountain]

Could be for live bird shooting? I have a 12g live bird gun, no safety, right Full, left IC, selective single trigger. From what I was told the first shot would be full and if the bird turned to an incomer you'd have IC.

[edgarspencer]

Reverse choked American guns are not common, except in large bore guns which were intended for waterfowl, generally over decoys.
Reverse choked English side by sides are common over here because they were brought in, relatively inexpensively (compared to conventionally choked sidelocks) because driven shooting in England and Scotland, popular in the late 19th century, and early 20th century has become rare, and expensive. Many of these imports have an H&H style single trigger, which was mostly non selective.
A boxlock W&C Scott, or Webley & Scott can be had well under $4k, and since they don't appreciate much, converting to screw-in chokes is an easy fix to make them more usable over here.