Remington Model 10: The Rarest American Trench Shotgun

From a channel Lumen includes in full: Forgotten Weapons is Ian McCollum's archive of firearms history: rare and historical guns examined in collections, with their design, mechanics and development documented from primary sources.

A 13-minute video from Forgotten Weapons's catalogue; the title names its topic.

Video by Forgotten Weapons, played through YouTube's embedded player.