Some years bck a clay target game known as "Mo-Skeet-O" as I recall was attempted to be popularized. Miniture clay targets were shot with smoothbore .22 rimfire shot cartridges through essentially regular rifles except for the bore. Supposedly one of the best was the "Rutledge" bore. This started as a regular .22 smoothbore for abut 6" & stepped up to a 5/16" bore with a choke. I have never shot oe of these but performance was supposedly much improved over a regular .22 bore.
Miller

Miller/TN
I Didn't Say Everything I Said, Yogi Berra