First off Im new to the board so I wanna say hi to everyone. Lately ive been shooting alot of .223 and Ive been kicking around the idea of having a pistol chambered in a .223. I know its kinda crazy but i was thinking it would be single shot break open, or a side x side or over under, cuz the case length. Probably around 12" barrel length.

My question is wat are the regulations or.... I guess the word would be qualifications to chamber this caliber as a pistol so it doesnt have to be a 16" rifle.