The Bored-Through Cylinder and the Self-Contained Cartridge (Rollin White, 1855) - History and How It Works

His first claim: "Extending the chambers a a of the rotating cylinder A right through the rear of the said cylinder." (US 12,648, dated 3 April 1855.)

With the chambers open at both ends, a cartridge (powder and ball made up as one unit) goes in from the back instead of being loaded loose from the front. White made the chambers slightly conical, smallest at the front, "in order that a cartridge may be inserted easily at the back, but that the ball may fit tight when it arrives in its place".

Once cartridges carried their own powder, ball and ignition in a metal case, a revolver could be reloaded in seconds from the back. Smith & Wesson built their first cartridge revolvers under a licence of White's patent.

From the text of US 12,648 (1855). His patent also describes a magazine and charging piston not covered here. This page gives no dimensions, charges or making steps, by design.