Charles Lancaster started his unmaking business in London in 1826, and it would survive more than one hundred years, being run after Charles’ death by his sons and then by an apprentice who bought out the firm in 1878. The company had an excellent reputation for quality, and did some pioneering work on developing the modern breechloading shotgun, as well as interesting technological developments like Lancaster’s oval-bore rifling. One of their most notable products was a series of 2-barrel and 4-barrel handguns, and they expanded the mechanism from those into a small number of 4-barrel shotguns (and an even smaller number of 4-barrel rifles).
This particular four-barrel shotgun is in 20 gauge, and exhibits a unique trigger mechanism derived from the pistols. It has two triggers, with the bottom one acting as a cocking lever and the top as a firing trigger. This allows the shooter to either cock the gun and then make a careful shot with the light upper trigger, or to pull all the way through with the upper trigger, much like a double action revolver. The reason for the system was that the firing mechanism had four firing pins but only one striker, which rotated to fire each barrel in sequence. The “cocking” action of the trigger was in fact the process of retracting the striker and rotating it to the next barrel.