 Colt's revolving rifles were quite effective against this, and the army purchased his products for use by troops in the Florida campaign.In 1855, with his Model 1855 patent, Colt introduced a spur-trigger revolver that featured a fully enclosed cylinder.These handguns were officially named Sidehammer revolvers, but they also were known as "Root" revolvers after Elisha K. Root, who at that time was employed as Colt's factory superintendent and Chief Engineer.