I feel your pain.
"Shelton's Challenge Gun Made in New Haven. Conn 1883 from patents of Clark R. Shelton. Hammer double-barrel with auxiliary barrel inserts for different chokes and rifle calibers." Wish I could learn more about Mr. Shelton. The not knowing brings to me eyes.
PS. They could add small part dedicated to vintage cartridge collecting and ole' shootin' tools much like Sporting Gazette and Sporting Gun do.