The Model 320 Revolving Rifle was one of Smith & Wesson's least successful commercial products, and as a result has become one of the most collectible of their guns - less that a thousand were ever made. The problem with the guns was the same problem that has plagued virtually all other revolving rifles: the cylinder gap sprays the shooter's forearms with hot gas and lead particles if they use the fore-end to support the gun. The S&W 320 was no exception. It was built on the action of the vastly more popular No. 3 revolver, and made with 16-, 18-, and 20-inch barrels (this particular one is the 20-inch type) with a detachable shoulder stock.