I remember an article many decades ago in Guns and Ammo - might even have been an annual, about Howdah pistols.
There was a 12 bore and a 4-barreled Lancaster .577 Snider chambered pistol in the article. Just checked - I no longer have that issue- probably loaned it out? I did find an article on The Return of the .45/70 by Al Miller I set aside to read.