The Model 1878 Zig-Zag revolver features Z pattern grooves in the cylinder that, in conjunction with a rod that moves forward when the hammer is cocked, cause the cylinder to rotate. The 3 5/8"" round with top rib 7.6mm barrel has a very good bore with frosting toward the muzzle. The revolver retains approx. 85% of its nickel finish with most loss at at the front of the cylinder area. The cylinder has three polished pitted areas where the gun must have been in a damp drawer or box. It sounds worse than it looks. The excellent hard rubber grips have a floral pattern with a fantasy creature at the bottom. The action functions properly. These interesting revolvers are rarely seen. Don't miss this one!