Shotgun adapter for pellet firing?

Well, I was thinking, what if there was something for shotguns similar to an auxillary cartridge, but the space was for a .22 caliber airgun pellet or something of that diameter propelled by a .209 primer? As in, put the pellet in the base of the shell, then put in the .209 primer? Before I consider inventing this, has it been done before?

I don’t know if this particular application has been tried before. However, shorgun adaptors have been made. Shotgun ammunition is out of my field, but I have a steel 12 gauge adaptor, size and shape of a normal 12 gauge shell, which incoporates a 9 x 19 mm Luger chamber behind a 9 mm rifled barrel, in essence turning a shotgun into a single shot 9 mm rifle. I acquired it because it related to the 9 mm Luger cartridge, a major specialty of mine. It is blued steel, with no visible markings.

Possibly made by these people L-W?

I did know about the adapters, but I meant for pellets in the above described configuration.

The idea of using a subcaliber adapter to propel a pellet or round ball by means of a primer must have more than 150 years old. Its application to shotshells haven’t as been popular as with rifle/pistol cartridges, but it has been made before. Like with most inventions, someone, every once in a while, fill a patent for the same basic design or a slight modification of the original idea. Hardly anything can be invented today.

Below you can see an example of a rifled shotshell subcaliber using a primer to propel a pellet:

Thanks Fede. Actually, (Not to be off-topic) you can invent things today. I made a sink plunger attached to a reciprocating saw for a school project. Searched the internet up and down but couldn’t find a single relevant result for “Motor driven sink plunger”.