It has blade and notch sights, "P" on top of the barrel, sling swivels on the barrel band and trigger guard, "Barnekov Greene Gun/K.V. Barnekov Patent/June 14th 1870" inscribed on the left side of the action, and a smooth stock and forearm. The forearm cap appears to be from a rifle that would have used a ramrod. Keil V. Barnekov was living in New York City when he patented this unusual action on June 14, 1870. The action has a toggle link mechanism, much like a Luger, except it is at an angle to the bore. When the large hammer is pulled to the rear, it pulls the breechblock with it, extracting the fired cartridge if there is one. There are tracks in both sides of the receiver, extending straight back from the lower edge of the chamber. Bosses on both sides of the breechblock ride in this track. The spring loaded firing pin is in the center of the breechblock with ears straddling the link between the hammer and the breechblock. As the hammer falls, pushing the cartridge into the chamber, the ears on both sides of the hammer strike the ears on both sides of the breechblock, driving the firing pin and firing the cartridge . When the cartridge is loaded into the chamber it is ready to fire as the gun fired from an open bolt. Cartridges are ejected through the hole in the bottom of the action in front of the trigger guard. Though there is a notch rear sight on the barrel, that sight cannot be used since the breech blocks the user's line of sight. Instead, there is a small notch on the hammer that can be used. A rifle-musket based on this design was entered into the U.S. 1872 trials but was eliminated well before the trials were completed.