There are two types of side by side actions, boxlocks and sidelocks. Sidelocks are the oldest of the two and are a carryover from the days of flint and percussion muzzleloaders. In the late 1700s, Joseph Manton built a side-by-side flintlock muzzloader that gave final form to the double gun, all that remained was the evolution of breechloading and bringing the hammers inside. As breechloaders took the helm the external hammers remained, and finally as hammerless shotguns overtook hammer guns, the sidelock design remained. The difference between a sidelock and boxlock action is that the sideloc