T-Perkins Double Barrel Shotgun. Guns & Military Artifacts > Large Estate Firearms Sale. Sometimes referred to by SxS, the side-by-side shotgun is a classic double-barrel shotgun that's equally well-suited for sport shooting and bird hunting. Treso . . A series of scratches is present on the left barrel at the breech. Even most well-provenanced guns attributed to famous western figures require some leap of faith. Probably abbreviation for one of the Pennsylvania Angstadt family. //